# Practice Problems - DOC by fjhuangjun

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```									Key to A Science 10 Balancing Act. . .

Balance each of the following equations using whole number
coefficients:

1. 2NaCl(aq) + 2H20(l)  2Na0H(aq) + Cl2(g)

2. 2N02(g) + 02(g)  2N03(g)

3. 2NH4 0H(aq) + C02(g)  (NH4)2C03(aq) + H20(l)

4. Fe203(S) + 3C0(g)  2Fe(S) + 3C02(g)

5. 2Sb(s) + 3Cl2(g)  2SbCl3(S)

6. 2HBr(aq) + Cl2(g)  2HCl(aq) + Br2(l)

7. 3N02(g) + H20(l)  2HNO3(aq) + N0(g)

8. Na2C03(S) + Ca(0H)2(S)  2Na0H(S) + CaC03(S)

9. CaC03(S)  Ca0(S) + C02(g) (no coefficients needed)

10. H2S207(S) + H20(l)  2H2S04(l)
Chapter Review:

Content Review:

1. Write the word equation for the reaction of zinc with copper (II) chloride to form copper
and zinc chloride. 9-1 zinc + copper (II) chloride  copper + zinc chloride.

2. What is the law of conservation of mass? 9-2 Total mass before reaction = total mass
after reaction.

3. Interpret the following equations. 9-2
a. 2Na + 2H20  2Na0H + H2
b. CaC03 + 2HCl  C02 + CaCl2 + H20

4. Tell which of the following are balanced equations. Assume that all formulas are correctly
written. 9-3
a. N2 + 2H2  2NH3 not correct
b. Ca(OH)2 + 2H2S04  CaS04 + 2H20 not correct
c. 2C2H2 + 502  4C02 + 2H20 correct

5. Use coefficients to balance each of the following equations: 9-4
a. NaCl  Na + Cl2    2NaCl  2Na + Cl2
b. Ti + N2  Ti3N4 3Ti + 2N  Ti3N4
c. Al + ZnCl2  AlCl3 + Zn 2Al + 3ZnCl2  2AlCl3 + 3Zn

6. The reaction between aluminum and oxygen gas produces aluminum oxide. 9-4
a. Write the word equation for this reaction.
b. Write the unbalanced formula equation for the reaction. Al + 02  2Al203
c. Balance the equation. 4Al + 302  2Al03

7. What is the difference between an endothermic reaction and exothermic
reaction? 9-5

8. Which of the following are ionic substances? Which are molecular? 9-7
a. HCl04 molecular                    c. Na2S ionic
b. NH4N03 ionic                       d. HBr molecular
9.    For each substance listed in question 8, how many of each ion is present in one
molecule or one formula unit? 9-7

10. Identify the category of each of these reactions: 9-8
a. calcium carbonate  calcium oxide + carbon dioxide
b. potassium bromide + chlorine  potassium chloride + bromine
c. tin + oxygen  tin (IV) oxide
d. zinc nitrate + hydrogen sulfide  zinc sulfide + nitric acid

11.   Write balanced formula equations for the reactions in question 10. 9-8

12. Complete and balance the following equations: 9-9
a. N2 + ?  NH3 N2 + 3H2  2NH3
b. S02 + ?  S03 2S02 + 02  2S03
c. ? + 02  H20   2H2 + 02  2H20
d. Fe + ?  Fe203 4Fe + 302  2Fe + 302  2Fe203

13. What is a catalyst? 9-10 a substance that increases the rate of a reaction.

14. Complete and balance the following equations: 9-10
a. KCl03  KCl + ? 2KCl03  2KCl + 302
b. Cu0  + ? 2Cu0  2Cu + 02
c. NO  ? + ? 2N0  N2 + 02
d. ?  H2 + I2   2HI  H2 + l2

15. Predict which of the following reactions will occur. 9-11
a. Zn + CuS04  Cu + ZnS04 yes
b. Li0H + Na  Na0H + Li      no

c. NaCl + Li  LiCl + Na yes
d. 2NaI + Br2  2NaBr + I2 yes

16. Predict which of the following reactions will occur. 9-12
a. (NH4)2C03(aq) + CaCl2(aq)    yes

b. NaN03(aq) + KBr no
c. KOH(aq) + H2S04(aq) yes
d. FeBr2(aq) + AlI3(aq) no
17. Write a balanced formula equation for each reaction in question 16 that occurs. 9-12
a.  CaC03(s) + 2NH4Cl(aq)    c.  K2S04(aq) + 2H20(l)

18. Write balanced ionic equations for each of the following: 9-13
a. CaBr2(aq) + Na2C0(aq)  CaC03(s) + NaBr(aq)
b. AgN03(aq) + NaCl(aq)  AgCl(s) + NaNo3(aq)
c. Zn(s) + AgN03(aq)  Zn(N03)2(aq) + Ag(s)
d. BaCl2(aq) + H2S04(aq)  BaS04(s) + HCl(aq)

19. Name the spectator ions in the four equations in question 18. 9-13
A. Na+, Br-,  B. Na+, N03- C. N03- D. H+, Cl-
Practice Problems:

Write balanced equations for each of the following:

1.   Cu + H20  CuO + H2
PROBLEM SOLVING HINT
2.   Al(NO3)3 + NaOH  Al(OH)3 + NaNO3
3.   KNO3  KNO2 + O2                              It is usually easier to balance
4.   Fe + H2SO4  Fe2(SO4)3 + H2                   the hydrogen and oxygen atoms
5.   O2 + CS2  CO2 + SO2                          last because they often appear in
6.   Cu + Cl2  CuCl2                              more than one place.
7.   Mg + N2  Mg3N2
Substitute symbols and formulas for names, and then balance the equation for each of the
following reactions.
8. When copper (II) carbonate is heated, it forms oxide and carbon dioxide gas.
Sodium reacts with water to produce sodium hydrogen gas.
9. Copper combines with sulfur to form copper (I)sulfide
10. Silver nitrate reacts with sulfuric acid to produce silver sulfate and
nitric acid.
11. Ethane, a component of natural gas, burns to produce carbon
dioxide and water.
12. Using one sentence for each, state the steps in writing a balanced formula equation.
13. Study each of the formula equations shown below. Use coefficients to
balance those equations that are not in balance.
a). Na + O2  Na2O
b). Cu + S  Cu2S
c). CuO + H2  Cu + H2O
d). Ba(OH)2 + CO2  BaCO3 + H20
14. The reaction between iron and oxygen gas produces iron (III) oxide.
a). Write the word equation for this reaction.
b). Write the unbalanced formula equation for the reaction.
c). Balance the equation.
15. Repeat the steps in question 14 for the reaction in which sodium and water react to produce
sodium hydroxide and hydrogen gas.
16. Repeat the steps in question 14 for the reaction between Cu and H2SO4 to produce copper
(II) sulfate, water, and sulfur dioxide.
Practice Problems:

1.    balanced
2.    Al(NO3) + 3NaOH 
Al(OH)3 + 3NaNO3
3.   2KNO3  2KNO2 + 02
4.    2Fe + 3H2SO4  Fe2(SO4) + 3H2
5.   302 + CS2  CO2 + 2SO2
6.   balanced
7.   3Mg + N2  Mg3N2
8.   CuCO3  CuO + CO2
9.   2Na + 2H2O  2NaOH + H2
10.   2Cu + S  Cu2S
11.   2AgNO3 + H2SO2  Ag2SO4 + 2HNO3
12.   2C2H6 + 702  4CO2 + 6H2O
13.   Write word eq.;
Write formulas;
Adjust coeff.
14.   a. 4Na + 02  2Na2O
b. 2Cu + S  Cu2S
c. balanced
d. balanced
15.   (See TG.)
16.   a. (See TG.)
b. Fe + O2  Fe2O3
17.   a. & b. (See TG.)
c. 2Na + 2H2O  2NaOH + H2
18.   (See TG.)
Review & Practice:

Write balanced equations for the following reactions:

1.       a.   W03 + H2  W + H20
b.   PdCl2 + HN03
c.   RbBr + AgCl  AgBr + RbCl
d.    HfCl3 + Al  HfCl2 + AlCl3
e.    Zn + CrCl3  CrCl2 + ZnCl2
f.    BaC03 + C + H20  C0 + Ba(0H)2
g.    Cu + H2S04  CuS04 + S02 + H20
h.     Pb(CH3C00)2(aq) + K2Cr04(aq)  PbCr04(cr) + KCH3C009(aq)
i.     RbCl(cr) + 02(g)  RbCl04(cr)
j.    SiF4(cr) + H20(l)  H2SiF6(aq) + H2SiO3(cr)
k.    Sn(cr) + KOH(aq)  K2Sn02(cr) + H2(g)

2. What mass of NH4Cl can be produced from 7.87 grams of NH3?

NH3 + HCl  NH4Cl

3. Substitute symbols and formulas for names and write balanced equations
for each of the reactions described below.
a). Ammonium nitrite decomposes to nitrogen gas and water.
b). Sulfuric acid decomposes to water and sulfur trioxide.
c). Ammonium nitrate decomposes to water and nitrogen (I) oxide.

4. Substitute symbols and formulas for names and write balanced equations
for each of the following reactions.
a). Chromium displaces hydrogen from hydrochloric acid, with chromium
(II) chloride as the other product.
b). Barium hydroxide reacts with carbon dioxide to form barium carbonate
and water.
c). Calcium carbonate decomposes to calcium oxide and carbon dioxide gas.
d). Calcium carbide, CaC2, reacts with water to produce calcium hydroxide and
ethyne gas (acetylene), C2H2.
e). Hydrogen combines with sulfur to form hydrogen sulfide.
f). Pentane burns in oxygen to produce carbon dioxide and water.
5. a.   W03 + 3H2  W + 3H20
b.   PdCl2 + 2HN03  Pd(NO3)2 + 2HCl
c.   balanced
d.   3HfCl3 + Al  3HfCl2 + AlCl3
e.   Zn + 2CrCl2  2CrCl2 + ZnCl2
f.   BaCO3 + C + H20  2C0 + Ba(OH)2
g.   Cu + 2H2SO4  CuSO4 + SO2 + 2H20
h.   Pb(CH3C00)2 + K2Cr04  PbCr04 + 2KCH3COO
i.   RbCl + 202  RbCl04
j.   3SiF4 + 3H20  2H2SiF6 + H2Si03
k.   Sn + 2K0H  K2Sn02 + H2

6. a. NH4NO2  N2 + 2H20
b. H2S04  H20 + S03
c. NH4NO3  2H20 + N20

7. a.   Cr + 2HCl  H2 + CrCl2
b.   Ba(OH)2 + CO2  BaCO3 + H20
c.   CaCO3  Ca0 + C02
d.   CaC2 + 2H20  Ca(0H)2 + C2H2
e.   H 2 + S  H 2S
f.   C5H12 + 802  5C02 + 6H20
Reaction Prediction

In many situations, one can predict the type of reaction which will occur if two substances are
combined with each other. Or, it may be possible to say whether no reaction at all will take place.
For each of the four most common types of reactions – synthesis, decomposition, single and double
replacement – certain rules allow one to make these predictions. Space does not permit us to list
these rules in detail here. However, the solved examples that follow illustrate the application of
these rules in specific situations.

Solved Examples

Example 1:     Predict whether a reaction between zinc metal and chlorine gas will take
place.

Solution:     The reaction between zinc and chlorine is potentially a synthesis reaction.
A synthesis reaction will occur provided the two elements involved are
capable of demonstrating opposite valences. In this case, zinc has a
valence of +2 and chlorine, of –1. Thus.

Zn + Cl2  ZnCl2

is the expected reaction.

Example 2: Predict whether a reaction will occur when mercury (ll) oxide is heated.

Solution:    This is potentially a decomposition reaction. Almost any decomposition
reaction will occur provided the proper conditions are supplied. The
expected reaction, then, is:
∆
2 Hg0            2 Hg + 02 ↑

Example 3: Predict whether a reaction between silver metal and copper (ll) nitrate
solution will occur.

Solution:    In a single replacement reaction like this one, the criterion is whether the
the element or the cation with which it is in “competition” is more active.
According to the Activity Series (Appendix 7, page 195), copper is the
more active element. Therefore, no reaction will occur.

Ag + Cu(NO3)2  NR
Example 4: Predict the nature of the reaction, if any, between solutions of barium
nitrate and sodium sulfate.

Solution:   The criterion for a double replacement reaction like this one is whether
bother reactants are soluble in water. Since they are, the reaction will
occur, as shown here.

Ba(N03)2 + Na2S04  2 NaN04  BaS04 ↓ + 2 NaN03

Also, since BaS04 is insoluble, the reaction goes to completion.
Reaction Prediction
Practice Problems (Level 1)

For each of the following problems, tell:

1.   What type of reaction might be expected
2.   Whether the reaction will occur or not
3.   If not, why it will not occur; then write the symbols and formula for the reactants
4.   If so, what the balanced equation for the reaction is
5.   In the case of double replacement reactions, whether the reaction goes to completion or not

1.   potassium and iodine
2.   Water electrolyzed
3.   Zinc and lead (ll) chloride
4.   Sodium nitrate and ammonium chloride
5.   Mercury and cadmium nitrate
6.   Manganese and sodium
7.   Silver nitrate and hydrogen sulfide
8.   potassium bromide electrolyzed
9.   mercury (l) sulfide and ammonium nitrate
10.    hydrogen and oxygen
Reaction Prediction
Practice Problems (Level 2)

For each of the following problems, tell:

1.   What type of reaction might be expected
2.   Whether the reaction will occur or not
3.   If not, why it will not occur; then write the symbols and formulas for the reactants
4.   If so, what the balanced equation for the reaction is
5.   In the case of double replacement reactions, whether the reaction goes to completion
or not

1. tin and copper (ll) sulfate

2. iron (lll) nitrate and sodium chromate

3. calcium and iodine

4. magnesium and hydrochloric acid

5. calcium oxide electrolyzed

6. carbon and oxygen

7. sodium carbonate and sulfuric acid

8. iron (ll) sulfide electrolyzed

9. platinum and lead (ll) nitrate

10. lithium oxide and water
Reaction Prediction
Teacher Notes

1. Explanation of Levels:

Level 1:   Predictions are all relatively simply made; equations are all easily balanced.

Level 2:   Predictions are somewhat more difficult than in Level 1; equations are
somewhat more difficult to balance.

Level 3:   Predictions involve less familiar instances, such as synthesis of oxides with
water and decomposition of ternary salts; equations are somewhat more
difficult to balance.

2. Answers:

Level 1:    (S = synthesis; D = decompostion; SR = single replacement; DR = double
replacement)

1.   S; yes; 2 K + l2  2 Kl
2.   D; yes; 2 H20 2         2 H 2 ↑ + 02 ↑
3.   SR; yes; Zn + PbCl2  Pb + ZnCl2
4.   DR; yes; NaN03 + NH4Cl           NaCl + NH4N03
5.   SR; no; Hg + Cd(N03)2
6.   S; no; Mn + Na
7.   DR; yes; 2 AgN03 + H2S  Ag2S ↓ + 2 HN03
8. D; yes; 2 KBr   ↔   2 K + Br2
9. DR; no; Hg2S04 + NH4N03
10. S; yes; 2 H2 + 02  2 H20

Level 2:     1.   SR; yes; Sn + CuS04  Cu + SnS04
2.   DR; yes; 2 Fe(NO3)3 + 3 Na2Cr04  Fe2(Cr04)3 ↓ + 6NaN03
3.   S; yes; Ca + l2  Cal2
4.   SR; yes; Mg + 2 HCl  MgCl2 + H2↑
5.   D; yes; CaO ∆ 2 Ca + 02
6.   S; yes; C + 02 ∆      C02↑
7.   DR; yes; Na2C03 + H2S04  Na2S04 + H2C03( H20 + C02↑)
8.   D; yes; FeS  Fe + S
9.   SR; no; Pt + Pb(NO3)2
10.   S; yes; Li20 + H20  2 Li0H
Chemistry 200

Balance the following equations: Also state what type of reaction each is for questions on
this page.

1.   Na0H + H2S04        Na2S04 + H20
2.   H2 + Cl2     HC1
3.   Zn + HC1      ZnC12 + H2
4.   CaC03 + HC1      CaC12 + C02 + H20
5.   K0H + H3P04       K3P04 + H20
6.   KC1 + AgN03       KN03 + AgC1
7.   Zn0 + HC1        ZnC12 + H20
8.     FeC13 + Fe       FeC12
9.     Zn + Na0H        Zn(0H)2 + Na
10.     H2S + S02      H 20 + S

Write formulas for the word equation and balance it.

1.   Sulphuric acid + ammonium hydroxide           ammonium sulphate + water
2.   Potassium hydroxide + hydrochloric acid          potassium chloride + water
3.   Potassium bromide + chlorine          potassium chloride + bromine
4.   Calcium oxide + water        calcium hydroxide
5.   Calcium chloride        calcium + chlorine
6.     Zinc + sulphuric acid       zinc sulphate + hydrogen
7.   Lithium iodide + bromine         lithium bromide + iodine
8.   Aluminum + sulphuric acid          aluminum sulphate + hydrogen
9.   Magnesium + oxygen          Magnesium oxide
10.   Iron + oxygen        Iron III oxide
11.   Calcium carbonate + hydrochloric acid         calcium chloride + water.
PART I

1. sodium bromide + barium chloride → _____________ + ______________
2. calcium nitrate + sodium carbonate → ____________ + ______________
3. ammonium chloride + sodium sulfate →____________ + _______________
4. potassium iodide + lead (II) nitrate → ____________ + ______________
5. magnesium iodide + sodium hydroxide → ___________ + ______________
6. aluminum sulfate + potassium hydroxide → __________ + _____________
7. Copper (I) chloride + zince nitrate → ______________ + _____________
8. lead (II) nitrate + sodium chloride → ______________ + _____________
9. silver nitrate + sodium chloride → ________________ + _____________
10. zinc chloride + potassium carbonate → _____________ + _____________

PART II

Write the names of the reactants:
Complete each equation by writing the names of the reactants in the blanks.

1.   _____________ + ____________ → silver chloride + aluminum nitrate
2. _____________ + ____________ → lead (II) sulfide + almmonium nitrate
3. _____________ + ____________ → magnesium hydroxide + potassium sulfate
4. _____________ + ____________ → copper (II) hydroxide + sodium sulfate
5. _____________ + ____________ → barium carbonate + sodium sulfate
6. _____________ + ____________ → potassium acetate + calcium sulfate
7. _____________ + ____________ → zinc carbonate + ammonium chloride
8. _____________ + ____________ → sodium nitrate + calcium phosphate
9. _____________ + ____________ → lead iodide + magnesium nitrate
10. _____________ + ____________ → silver bromide + calcium nitrate
Equation Writing

A chemical equation is a way of using chemical symbols and formulas to express the
changes that take place in a chemical reaction. All chemical equations must conform to the law of
conservation of mass. This means that no atoms may be created in or lost from any chemical
change. The process by which a chemical equation is made to conform to this law is known as
balancing the equation.

Balancing an equation involves basically two steps.

1. Formulas for all substances involved in the reaction must be
written correctly. If an improper formula is assigned to a reactant
or a product, the equation cannot be properly balanced.

2. Coefficients must be assigned to all formulas such that the number of
atoms of each kind on the left side of the equation is identical to the
to the number of atoms of the same kind on the right side. Formulas
of substances may NOT be written in order to achieve this balance.

Solved Examples:

Example 1: Balance this equation: Ca + HCl → CaCl2 + H2

Solution:      In balancing an equation, it is usually best to leave hydrogens and
and oxygens to the end. Notice in this case that there is only one
“Cl” on the left and two on the right. To balance the “Cl’s” place a
coefficient of 2 in front of the HCl:

Ca + 2 HCl → CaCl2 + H2 

Notice that the number of hydrogens also balances now. The full
equation is balanced.
Example 2: Write and balance the equation for the reaction in which sodium
carbonate and aluminum hydroxide react to form sodium hydroxide
and aluminum carbonate.

Solution:   Begin by writing the correct formulas for all substances involved:

Na2CO3 + Al(OH)3 → NaOH + Al2(CO3)3

In balancing this equation, think of all poloyatomic ions as a single
element. Balance carbonates (CO3) first. Since there are 3 on the
right in Al2(CO3)3, add a coefficient of 3 in front of the Na2CO3:

3 Na2C03 + Al(OH)3 → 6 NaOH + Al2(CO3)3

Now balance sodiums (Na). Since there are 6 (3 X 2) on the left,
add a coefficient of 6 in front of the NaOH on the right.

3 Na2CO3 + Al(OH)3 → 6 NaOH + Al2(CO3)3

Now balance hydroxides (OH). There are 6 on the right in 6 NaOH.
So add a coefficent of 2 (2 X 3 = 6) in front of the Al(OH)3. Notice
that this balances the aluminums (Al) at the same time, and the
equation is fully balanced.

3 Na2CO3 + 2 Al(OH)3 → 6 NaOH + Al2(CO3)3
Equation Writing
Practice Problems (Level 1)

1.   Balance each of the following equations.
a. Zn + H2SO4  ZnSO4 + H2

b. Na + Br2  NaBr

c. H2O  H2  + O2 

d. Cl2 + Kl  KCl + l2

e. HNO3 + LiOH  H2O + LiNO3

f. N2 + O2  N2O

g. NH4Cl + NaOH  NH4OH + NaCl

h. HCl + K2CO3  KCl + H2O + CO2 

2.   Balance each of the following eqations.

a. sodium + iodine  sodium iodide

b. zinc + hydrobromic acid  zince bromide + hydrogen 
heated
c. potassium hydroxide               potassium oxide + water

d. magnesium + water  magnesium hydroxide + hydrogen 
Equation Writing
Practice Problems (Level 2)

1.   Balance each of the following equations.

a.   K3PO4 + HCl  KCl + H3PO4

b.   Na + HNO3  NaNO3 + H2

c.   S + O2  SO3 

d.   Ca(Cl03)2    ∆        CaCl2 + O2 

2.   Balance each of the following equations.

a.   potassium iodide + lead (ll) nitrate  potassium nitrate + lead (ll) iodide

b.   iron (lll) oxide + carbon  carbon monoxide  + iron
heated
c.   mercury (ll) oxide            mercury + oxygen 

d.   calcium + aluminum chloride  calcium chloride + aluminum

e.   mercury (l) nitrate + sodium carbonate  sodium nitrate + mercury (l) carbonate

f.   potassium bromide + aluminum nitrate  potassium nitrate + aluminum bromide

g.   calcium phosphate + aluminum sulfate  calcium sulfate + aluminum phosphate

h.   rubidium + acetic acid  rubidium acetate + hydrogen 
Chemistry 200 Moles/Mass Review

Show work as much as possible.

1.   Find mass of 4.5 moles of copper II sulfate.

2.   How many moles are in 285 grams of Al Cl?

3.   Calculate the number of moles in 8.16 x 1024 molecules.

4.   Find mass of 6 molecules of C12 H22011.

5.   Find mass of 9.36 moles of Ca(OH)2.

6.   Calculate moles in 438 grams of CuCl2.

7.   10.692 moles of NH4NO3 = _______________ molecules.

8.   How many moles in 8.62 x 1025 molecules of Cu?

9.   Find mass of 6.02 x 1025 molecules of Mg (OH)2.

10.   Calculate the number of molecules in 20g of MnO2.
CHEMISTRY 30S MOLES/MASS/NUMBER/MOLARITY PRACTICE

1. What is the mass of 2.00 molecules of methane (CH4).

2. How many moles are in 123.8 grams of FeCl3?

3. How many moles are in 3.54 x 1023 molecules?

4. How many particles are in a mole of any substance?

5. What is the mass of 2.37 moles of LiF?

6. How many moles are in 74.9 grams of CuCl2?

7. How many molecules are in 0.137 moles of KBr?

8. How many moles are in 2.47 x 1022 formula units of Mg(0H)2?

9. What is the mass of 6.49 x 1026 formula units of Mg(OH)2?

10. How many molecules are in 0.675 grams of FeS?
CHEMISTRY 30S
SINGLE DISPLACEMENT REACTION: QUALITATIVE ANLYSIS

PURPOSE:       -      To react iron filings with copper sulfate
-      Calculate the moles of Fe reacted & moles of Cu produced
-      Determine the mole ratio of Fe: Cu and write a balanced equation.

MATERIALS:          100 ML BEAKER, STIRRING ROD, WEIGHING PAPER, CuSO4 crystals,
Fe filings.

PROCEDURE:     1.     Mass a 100 ml beaker and record the exact mass.
2.     Add 25 ml of CuSO4 solution to beaker.
3.     Mass about 2 g of Fe on weighing paper and record exact mass.
4.     Add Fe gradually to CuSO4 solution and allow 10 minutes for reaction to
complete. Stir occasionally. You will see copper at bottom of beaker.
5.     Decant solution. Add another 10 ml of CuSO4(aq). Stir, decant again.
Wash a couple of times with 10 ml of distilled water. (Decant is pouring
off solution by using a stirring rod in beaker to hold back the copper)
6.     Dry solid overnight in oven and determine mass.

DATA:          Mass of empty 100 ml beaker                  ______________________
Mass of Fe used                              ______________________
Moles of iron used                           ______________________
Mass of dried copper & beaker                ______________________
Mass of copper                               ______________________
Moles of copper produced                     ______________________
Ratio of Fe: Cu                              ______________________

OBSERVATION:
What evidence is there that some of the copper ions in solution remained
unchanged?

CONCLUSION:
1.     Write a balance equation for the reaction.

2.     Name the limiting reactant, and explain how you determined your answer.
Molecular Weight and Moles

The relative weights of elements are represented by their atomic weights. The relative
weights of compounds are represented by their molecular of formula weights. (The terms atomic
mass, molecular mass, and formula mass are more precise, but the use of the term weight still
tends to be more common.)

The molecular or formula weight of a compound is equal to the sum of the weights of all
atoms present in the molecule or formula unit. The molecular or formula weight of a substance is
often expressed in units of grams. At one time, the quantity gram molecular weight or gram
formula weight was given the designation mole. Today, a somewhat more technical definition is
given for this term. A mole is defined as the amount of a substance containing 6.02 + 1023
particles (atoms, molecules, ions, etc.). This number is known as the Avogadro number.

Solved Examples
Example 1:    Find the molecular weight of ethyl lcohol, C2H5OH.

Solution:     The molecular weight is equal to the sum of the weights of all atoms in the
molecule.

Molecular weight = 2 x C + 6 x H + 1 x 0
= 2 x 12.01 + 6 x 1.01 + 1 x 16.00
= 46.08

Example 2:    Find the weight of one mole (1.00 mol) of sulfuric acid.

Solution:     1.00 mol of H2SO4 = 1.00 gram molecular weight (gmw) of H2S04
= 2 x H + 1 x S + 4 x 0 (in grams)
= 2 x 1.01 + 1 x 32.06 + 4 x 16.00 g
= 98.08 g

Example 3:    What is the weight of 0.435 mol of water?

Solution:     0.435 mol of H2O = 0.435 mol x gmw of H2O
= 0.435 mol x (2 x 1.01 + 1 x 16.00) g
mol
= 0.435 mol x 18.02 g
mol
= 7.84 g
Example 4:   How many moles of sodium chloride is 15.0 g of the substance?

Solution:    1.00 mol of NaCl = 1 x 23.0 + 1 x 35.45 g = 58.45 g

15.0 g x 1.00mol = 0.257 mol of Nacl
58.45 g
Molecular Weight and Moles
Practice Problems (Level 1)

1.   Find the molecular of formula weight of each of the following compounds.

a.   KCl                                   f.   BaCl2
b.   NaF                                   g.   Cal2
c.   Hl                                    h.   Na2S
d.   LiBr                                  i.   MgS
e.   RbBr                                  j.   AlP

2.   Find the weight of each of the following expressed in grams.

a.   1.00 mol of CaO                       f.   2.00 mol of Li3P
b.   1.00 mol of BeSe                      g.   5.00 mol of CaCl2
c.   1.00 mol of KF                        h.   0.50 mol of FeBr2
d.   1.00 mol of Sr0                       i.   0.20 mol of Cu20
e.   2.00 mol of Mgl2                      j.   0.40 mol of Hg2Cl2

3.   Find the weight of each of the following, expressed in moles.

a.   18.02 g of H2O                        f.   25.38 g of Snl2
b.   80.92 g of HBr                        g.   11.98 g of Fe0
c.   17.04 g of NH3                        h.   15.0 g of KBr
d.   190.42 g of MgCl2                     i.   25.0 g of SrS
e.   36.75 g of K2S                        j.   50.0 g of AlF3
Molecular Weight and Moles
Practice Problems (Level 2)

1.   Find the molecular weight or formula weight of each of the following compounds.

a.   HNO3                                        f.   ammonium nitrate
b.   Fe2O3                                       g.   rubidium sulfite
c.   H3P04                                       h.   lithium carbonate
d.   K2S04                                       i.   magnesium hydroxide
e.   Be5As2                                      j.   aluminum sulfate

2.   Find the weight of each of the following, expressed in grams.

a.   1.00 mol of HC2H3O2                         f.   0.25 mol of sodium acetate
b.   2.50 mol of K2CrO4                          g.   0.152 mol of phosphoric acid
c.   0.50 mol of Ca(ClO3)2                       h.   0.0582 mol of lithium sulfate
d.   0.25 mol of Ba(NO3)2                        i.   0.418 mol of iron (lll) nitrate
e.   Be5As2                                      j.   aluminum sulfate

3.   Find the weight of each of the following, expressed in moles.

a.   100.00 g of CaCO3                           f.   3.50 g of arsenic trichloride
b.   100.00 g of Ni(NO3)2                        g.   0.572 g of calcium phosphide
c.   50.00 g of C6H12O6                          h.   1.750 g of calcium acetate
d.   25.00 g of K3PO4                            i.   4.904 g of aluminum nitrate
e.   15.57 g of Bi(OH)3                          j.   27.85 g of iron (ll) phosphate
MoleParticle Calculations

1.   How many molecules are then in 7.21 moles of H2O?

2.   How many moles are there in 5.97 x 1022 molecules of H2SO4?

3.   How many molecules are there in   a). 7.5 moles C6H12O6
b). 1.85 moles KNO3
c). 0.45 moles NaC1

4.   How many moles are there in 8.23 x 1021 molecules C6H12O6?

5.   We have 1.72 x 1021 molecules KNO3, how many moles is this?

6.   How many moles are there in 5.36 x 1024 molecules H2O?

7.   We have 3.9 moles NaHCO3, how many molecules is this?

8.   There is 1.91 x 1023 molecules of NaBr, how many moles is there?
Molar Volumes of Gases

1 mole of CO2 gas = 22.4 litres at STP = 44 grams = 6.02 x 10^23 molecules

1 mole of N2 gas = _____litres at STP= ____ grams = ______________ molecules

0.5 mole 02 gas = _____litres at STP = ____ grams = ______________ molecules

____mole NO gas = 44.8 litres at STP= _____ grams = ______________molecules

____mole CO gas = ____litres at STP = _____ grams = 6.02 x 10^22 molecules

____mole H2 gas = ____litres at STP = 20 grams = _________________molecules
MASSPARTICLE CONVERSIONS

1.   492G OF Ba(NO3)2 will have how many molecules?

2.   75.0g of C6H12O6 has how many molecules?

3.   How many molecules are in 36.0g of C6H12O6?

4.   We have 3.92 x 1023 molecules of C6H12O6. How many grams are there?

5.   There are 9.34 x 1024 molecules of NaHCO3. How many grams are there?

6.   How many grams are there in 7.81 x 1022 molecules of NaHCO3?

7.   How many molecules are there in 24.8g of NaHCO3?

8.   In 5.07 x 1025 molecules of Ba(NO3)2, how many grams would there be?
MoleMolecular Mass Calculations

1.   What is the mass of 4.5 moles of sugar C6H12O6?

2.   What is the mass of 3.75 moles of NaCl?

3.   What is the mass of 103 moles of H2O?

4.   How many moels are there in 752g AlCl3?

5.   How many moles are there in 752 g of CuSO4?

6.   How many moles are there in 752 g of NaHCO3?

7.   How many moles are there in 54g of K2CrO4?

8.   What is the mass of 2.50 moles of K2CrO4?

9.   How many moles are in 23.7g Zn(OH)2?

10.   What is the mass of 4.06 moles of CuSO4?
EQUATIONS

Write a balanced chemical equation to represent each of the following chemical reactions:

1.   iron + sulfur -> iron (II) sulfide

2.   zinc + cupric sulfate -> zinc sulfate + copper

3.   silver nitrate + sodium bromide -> sodium nitrate + silver bromide

4.   potassium chlorate (heated) -> potassium chloride + oxygen

5.   water (electricity) -> hydrogen + oxygen

6.   mercury (II) oxide (heated) -> mercury + oxygen

7.   potassium iodide + lead (II) nitrate -> lead (II) iodide + potassium nitrate

8.   aluminum + oxygen -> aluminum oxide

9.   magnesium chloride + ammonium nitrate -> magnesium nitrate + ammonium chloride

10.   iron (III) chloride + ammonium hydroxide -> iron (III) hydroxide + ammonium chloride

11.   sodium peroxide + water -> sodium hydroxide + oxygen

12.   iron (III) oxide + carbon -> iron + carbon monoxide

13.   iron + water -> hydrogen _ iron + carbon monoxide

14.   iron (III) chloride + potassium hydroxide  potassium chloride + iron (III) hydroxide

15.   aluminum + sulfuric acid -> aluminum sulfate + hydrogen

16.   sodium carbonate + calcium hydroxide -> sodium hydroxide + calcium carbonate

17.   carbon dioxide + water -> carbonic acid

18.   phosphorus + oxygen -> phosphorus pentoxide

19.   sodium + water -> sodium hydroxide + hydrogen

20.   zinc + sulfuric acid -> zinc sulfate + hydrogen
21.   aluminum sulfate + calcium hydroxide -> aluminum hydroxide + calcium sulfate

22.   calcium oxide + water -> calcium hydroxide

23.   iron + copper (I) nitrate -> iron (II) nitrate + copper
Chemistry-Writing and Balancing Equations

1.   Nitrogen dioxide gas dissolves in water to form nitric acid solution and nitric oxide (or
nitrogen monoxide).

2.   Aluminum oxide dissolves in sulfuric acid to produce water and aluminum sulfate.

3.   Calcium metal reacts with water to form calcium hydroxide and hydrogen.

4.   Butane burns in a limited supply of oxygen to form carbon monoxide and water vapour.

5.   Ferric nitrate reacts with sodium hydroxide to form ferric hydroxide and sodium nitrate.

6.   Phosphoric acid reacts with sodium hydroxide to form the salt, sodium dihydrogen
phosphate, and water.

7.   Sodium bicarbonate reacts with sulfuric acid to produce sodium sulfate, water and carbon
dioxide gas.

8.   Heptane, C7H16 burns in air combining with the oxygen gas to produce water vapour and
carbon dioxide gas.

9.   Manganese metal dissolves in nitric acid to produce manganese (II) nitrate solution, nitrogen
dioxide gas, and water.

10.   Sodium metal reacts violently with water to form sodium hydroxide solution and hydrogen
gas.

11.   Solid sodium hydroxide reacts with chlorine gas to form solid sodium chloride, solid sodium
chlorate and water.

12.   Phosphorous trichloride reacts with hydrogen gas to form phosphine, PH3, and hydrogen
chloride.

13.   Calcium hydride reacts with water to produce hydrogen gas and calcium hydroxide.

14.   Sulfur, S8, reacts with oxygen gas to form sulfur trioxide solid.

15.   Aluminum metal dissolves in hydrochloric acid to produce hydrogen gas and aluminum
chloride.

16.   Ethanol, CH3CH2OH burns (combines with oxygen gas O2) to form carbon dioxide gas and
water vapour.
Types of Reactions

The four types of chemical reactions are: (1) decomposition; (2) combination(synthesis);
(3) single displacement; (4) double displacement.
Write formula-equations for the chemical reactions listed under each of the four types below.

1.    Simple decomposition.

a).   Electroysis of water

b).   Decomposition of mercuric oxide

c).   Decomposition of potassium-chlorate

2.    Direct combination.

a).   Burning carbon

b).   Union of hydrogen and chlorine

c).   Union of zinc and sulfur

3.    Single replacement

a).   Action of hydrochloric acid on zinc

b).   Action of sodium on water

c).   Action of hydrogen on copper oxide {use copper (II)}

d).   Action of iron on copper sulfate solution

e).   Action of steam on hot iron
4.   Double displacement.

a).   Reaction between calcium carbonate and hydrochloric acid.

b).   Reaction between nitric acid and sodium hydroxide

c).   Reaction between solutions of silver nitrate and sodium chloride

d).   Reaction between calcium hydroxide and sulfuric acid

e).   Reaction between sodium chloride and sulfuric acid

The Following pages are REVIEW and are for extra practice
and study
TYPES OF CHEMICAL REACTIONS

Introduction:

It is not an easy matter to classify all chemical reactions as some are very complex, however we
can classify many using ___ major categories.

1.      Combination reactions or synthesis:
2H2 + O2  2H2O

S + O2  SO2

2.      Decomposition reactions:
carbonic acid (in soft drinks)                       carbon dioxide ÷ water
H2CO3                                               CO2 + H2O

3.      Displacement or substitution:
2NaBr + Cl2  2NaCl + Br2

4.      Double displacement:
NaCl + AgNO3  AgCl + NaNO3

5.      Combustion (reaction with oxygen)
CH4 + 202  CO2 + 2H2O

Data:

The above examples illustrate the five major categories. Your job is to try to recognize what
kind of reaction is taking place as this will greatly help in writing a chemical equation for the
reaction.

Purpose: To become acquainted with different chemical reactions and to write chemical
equations.
1. PREDICT THE TYPE OF REACTION.
2. Write a word equation and a formula equation.
3. Record your observations
4. Balance the equation.
Collect the data for each lab in a table like this:
Type of Reaction:
Products Expected:
Word Equation:
Chemical Equation:
Observations:

Procedure:

Lab A:

Put a few crystals of lead (II) nitrate into a small test tube. Heat gently and listen carefully.
Test the gas with a glowing splint. The residue that remains should be PbO.

Lab B:

Hold a 3 cm piece of Mg metal with a pair of crucible tongs. Insert in a flame and do not look
directly at the reaction.

Lab C:

Place a piece of mossy zinc in about 5 ml of dilute H2SO2. Test the gas with a burning splint.

Lab D:

Drop a small clean nail into a solution of cupric sulfate. Take it out after a few minutes.

Lab E:

Add about 5 ml sodium sulfate solution to about 5 ml of barium chloride solution.

Lab F:

Add a very small quantity of manganese dioxide to a solution of hydrogen peroxide H2O2. Test
the gas with a glowing splint. (MnO2 acts as a catalyst and does not appear in the equation).

Lab G:

Add 5 ml of ferric nitrate solution to 5 ml of potassium chromate. (The precipitate is ferric
chromate)

Lab H:

Add 5 ml of lead nitrate solution to 5 ml of sodium iodide solution.
Check to see that all of the equations in this experiment have been balanced.

Exercise in Predicting Results of Chemical Reactions:

Reaction Type

______     1.    HCl + K0H  _____ + _____

______     2.    HCl + CaC03  CaCl2 + _____ + H2O

______     3.    Mg + Cl2  ______

______     4.    H2SO4 + Mg  ______ + _______

______     5.    MgCO3 + HCl  ______ + CO2 + MgCl2

______     6.    Cu + O2  _______

______     7.    H 2O  H 2 + O 2

______     8.    Zn + O2  _____

______     9.    AgNO3 + K2CrO4  ____ + Ag2CrO4

______    10.    NH4Cl + AgNO3  NH4NO3 + ________
MAKE SURE THAT THE ABOVE EQUATIONS ARE BALANCED:
Writing Equations of Chemical Reactions

For each reaction, write a word, skeleton and balanced equation.

A.    Sodium and chlorine react to produce sodium chloride.

W.E:

S.E:

B.E:

B.    Water decomposes into hydrogen gas and oxygen gas.

W.E:

S.E:

B.E:

C.    Hydrogen chloride reacts with magnesium metal and forms hydrogen gas and magnesium
chloride.

W.E:

S.E:

B.E:

D.    Iron (II) nitride and calcium sulfate react. Iron (II) sulfate and calcium nitride are
produced.

W.E:

S.E:

B.E:
E.   Carbon dioxide breaks down into two elements

W.E:

S.E:

B.E:

F.   Copper (II) phosphite and another element form when aluminum phosphite reacts with
copper metal.

W.E:

S.E:

B.E:

G.   Hydrogen gas and the hydroxide ion form water molecules.

W.E:

S.E:

B.E:

H.   Glucose (C6H12O6) and oxygen are produced when plants combine carbon dioxide and water.

W.E:

S.E:

B.E:
Balancing Equations
Balance the following chemical equations…..

1. ____Na + ___I2  ___ NaI

2. ____N2 + ___O2  ___N2O

3. ____N2 + ___H2  ___NH3

4. ____KI + ___Cl2  ___KCl + ___I2

5. ____HCl + ___Ca(OH)2  CaCl2 + ___HOH

6. ____S + ___ O2  ___ SO3

7. ____H2O2  ___H2O + ___ O2

8. ___CH4 + ___O2  ___ CO2 + ___H2O

9. ___C2H6 + ___ O2  ___CO2 + ___H2O

10. ___C3H8 + ___O2  ___CO2 + ___H2O

11. ___C4H4 + ___O2  ___CO2 + ___H2O

12. ___C8H18 +___O2  ___CO2 + ___H2O

13. ___NaCl + ___F2  ___NaF + ___Cl2

14. ___ P + ___O2  ___ P2O5

15. ___Ag2O  ___ Ag + ___ O2

16. ___S8 + ___ O2  ___ SO3

17. ___CO2 + ___ H2O  ___C6H12O6 + ____ O2

18. ___ K + ___ MgBr2  ___ KBr + ___ NaCl

19. ___FeCl3 + ___NaOH  ___ Fe(OH)3 + ___ NaCl

20. ___HCl + ____CaCO3  ___CaCl2 + ___ H2O+ ___ CO2
Extra Balancing Practice
Good luck!!!!

1.   ___C8H18 + ___ O2  ___ CO2 + ___ H2O

2.   ___Pb(NO3)2 + ___K2CrO4  ___ PbCrO4 + ___ KNO3

3.   ___MnO2 + ___ HCl  ___MnCl2 + ___H2O + ___ Cl2

4.   ___C3H8 + ___O2  ___ CO2 + ___H2O

5.   ___BaO2  ___ BaO + ___ O2

6.   ___Zn(OH)2 + ___ H3PO4  Zn3(PO4)2 + ___ H2O

7.   ___CO + ___Fe2O3  ___ Fe + ___ CO2

8.   ___CS2 + ___ Cl2  ___CCl4 + ___ S2Cl2

9.   ___CH4 + ___ Br2  ___ CH3Br + ___ HBr

10.   ___Ba(CN)2 + ___ H2SO4  ___ BaSO4+ ___ HCN

11.   ___(NH4)2Cr2O7  ___Cr2O3 + ___ H2O + ___N2

12.   ___CrCl3 + ___ H2SO4  ___ Cr2(SO4)3 + ___HCl

13.   ___Mg(HCO3)2 + ___HCl  ___ MgCl2 + ___ H2O + ___CO2

14.   ___Al2S3 + ___NaHCO3 + ___ O2  ___Al(OH)3 + ___Na2SO4 + ___ CO2

15.   ___NH4C2H3O2 + ___ FeCl2  ___ NH4Cl + ___ Fe(C2H3O2)2

16.   ___Fes + ___O2  ___ Fe2O3 + ___ SO2

17.   ___Ca3(PO4)2 + ___ SiO2 + ___ CO  ___P + ___C + ___CaSi2O7

18.   ___KmnO4 + ___ H2SO4 + ___H2S  ___ MnSO4 + ___ K2SO4 + ___S + ___ H2O

19.   ___K2Cr2O7 + ___HCl  ___KCl + ___CrCl3 + ___H2O + ___Cl2

20.   ___CrI3 + ___KOH + ___Cl2  ___K2CrO4 + ___KIO4 + ___KCl + ___ H2O
CHEMICAL REACTIONS
CLASSIFYING REACITONS AND BALANCING CHEMICAL
EQUATIONS

Classify each of the following reactions by writing sc,sd,sr,dr, hc or o to the left of the
equation. Balance the equations using the simplest whole numbers possible.

_____      1.   _____Cu(s) + ____O2(g)                 _________CuO(s)

_____      2.   _____H2O(1)           ____H2(g) + _______O2(g)

_____      3.   _____Fe(s) + _____H2O(g)              _____ H2(g) + ___Fe3O4(s)

_____      4.   _____AsCl3(aq) + ____H2S(aq)               ___As2S3(s) + ____HCl(aq)

_____      5.   _____CuSO4 + 5H20(s)                 ___ CuSO4(s) + ____ H2O(g)

_____      6.   _____Fe2O3(s) + ____H2(g)             ____Fe(s) + ____H2O(1)

_____      7.   _____CaCO3(s)            ___CaO(s) + ___CO2(g)

_____      8.   _____Fe(s) + ___ S8(s)             ____FeS(s)

_____      9.   _____H2S(aq) + ___ KOH(aq)              _____HOH(1) + ____K2S(aq)

_____     10.   _____NaCl(1)             ____Na(1) + ____Cl2(g)

_______   11.   _____Al(s) + ______H2SO4(aq)              ____H2(g) + _____Al2(SO4)3(aq)

_____     12.   _____H3PO4(aq) + ____NH4OH(aq)              ____HOH(1) - ___(NH4)3PO4(aq)

_____     13.   _____C3H8(g) + ___O2(g)            ____CO2(g) +____H2O(g)

_____     14.   _____Al(s) - ___O2(g)                ____Al2O2(s)

_____     15.   _____CH4(g) - ____O2(g)            C02(g) + _____H2O(g)
Predicting Products of Chemical Reactions
For each of the following reactions, identify the reaction type, predict what will be
produced and balanced.

Reaction Type                     Reactants                        Products

1.   ____________              ____Ca+____Cl2                   __ ____________

2.   ____________              ____H2SO4+ __I2                 __ ____ + __ _____

3.   ____________              ____C3H8+ ___O2                 __ ____ + __ _____

4.   ____________              ____BaBr2+___AlPO3             __ ____ + __ _____

5.   ____________              ____ Al2O3  heat               __ ____ + __ _____

6.   ____________              ____H2 + ___O2                   __ ______________

7. ____________                ____Fe + ___CuI2               ___ ______ + __ _____

8. ____________                ____C6H12O6+ __O2              ___ ______ + __ _____

9. ____________                ____Ca(OH)2 + __H3PO4          ___ ______ + __ _____

10. ____________                ____Li + ___ CaO               ___ ______ + __ _____

11. ____________                ____LiBr + ___MgS              ___ ______ + __ _____

12. ____________                ____Al(NO3)3 + ___ K           ___ ______ + __ _____

13. ____________                ____K3N                        ___ ______ + ___ _____

14. ____________                ____C5H12 + ___ O2             ___ ______ + ___ _____

15. ____________                ____Pb(IV) + ___ O2            ___ ________________
MOLE CONVERSIONS
Practice Problems

1.     1.00 moles Zn                       = _________________atoms

2.     1.00 moles Cu                       = _________________atoms

3.     4.00 moles Ag                       = _________________atoms

4.     0.186 moles Sn                      = _________________atoms

5.     4.90 x 1018 atoms C                 = _________________moles

6.     1.69 x 1028 atoms U                 = _________________moles

7.     1.00 moles CO2                      = _________________molecules

8.     1.00 moles NaCl                     = _________________formula

units

9.     4.50 moles H2O                      = _________________molecules

10.     2.96 x 10-3 moles CaCl2             = _________________formula

units

11.     9.28 x 1023 molecules H2S           = _________________molecules

12.     4.23 x 1022 formula units NaF       = _________________moles

13.     1.00 mol H2O                        = _________________atoms

14.     4.39 x 1024 atoms                   = _________________moles CO2

15.     4.5 moles CO2                       = _________________atoms

16.     2.8 moles aluminum chloride         = _________________atoms

17.     2.23 x 1024 atoms                   = _________________moles

H2SO4

18.     9.5 moles Li2O                      = _________________atoms Li

19.     5.00 moles sodium phosphide         = _________________atoms P

20.     2.05 x 1025 atoms hydrogen          = _________________moles CH4
MOLE CONVERSIONS

A FEW MASS CONVERSIONS

1.   What is the mass (in grams) of 1.00 moles of copper atoms?

2.   How many moles are 4.00g of helium atoms?

3.   What is the mass of 3.56 moles of zinc?

4.   What is the mass of 1.00 moles of water molecules?

5.   How many moles are found in 7.95g of lithium chloride?

6.   What is the mass of 4.50 mol of aluminum chloride?

7.   Convert 250g of calcium hydroxide into moles.

8.   You are given 365g of sugar (C6H12O6)
a). How many moles would you have?

b). How many molecules?

c). How many hydrogen atoms?
Chemistry 20 Stoichiometry
Moles to Moles Conversions
Show ALL of your work

1.              ___H2O  ___H2 + ___O2
If you break down 6.00 moles of water, how many moles of each product
will be produced?

2.                   ___CH4 + ___ O2  ___CO2 + ___ H2O
If 7.06 moles of water are produced, how many moles of each reactant reacted?

3. If you burn propane (C3H8) and produce 5.00 mol of CO2, how many moles of oxygen
did you also burn? How many moles of the other product are produced?

4. Zinc reacts with hydrogen chloride. If 4.60 mol of hydrogen gas is produced, how
many moles of zinc reacted? How many moles of hydrogen chloride reacted?

5. Aluminum hydroxide reacts with 3.25 mol of H2SO4. How many moles of each product
are produced?
Chemistry 20 Stoichiometry Practice

1.     4 mol               xmol
2 H2 + 1 O2  2 H2O

2.       xmol 15.6g y mol
___HgO  ____Hg + ___O2

3.     7.45 mol   x grams                          y grams
___Al2(SO4)3 + ___Ca(OH)2  ____Al(OH)3 + ___CaSO4

4.                  8.3 grams   x grams        y grams
___Cu + ____AgNO3  ___Cu(NO3)2 + ___Ag

5.     In a reaction 15g of tricarbon pentahydride react with oxygen. Write a balanced
equation and find out the mass of each reactant and produce in the reaction.
Mole/Gram Conversions Practice
Include units.
1.   Convert to moles. . . .
a). 18.3 grams of aluminum sulfate
b). 5.40g of cupric sulfate
c). 182g of zinc acetate
d). 49.5g of potassium chlorate
e). 100.g of iron
f). 231g of chlorine gas
g). 100.g of sodium iodide
h). 0.730g of copper
i). 8.41g of lead (II) nitrate
j). 8.13g of sodium sulfate

2.   Convert to grams. . . .
a). 3.00 moles of oxygen gas
b). 1.40 moles of lithium hydroxide
c). 5.80 moles of potassium chloride
d). 2.50 moles of water
e). 0.700 moles of zinc
f). 6.30 moles of hydrogen sulfate
g). 7.25 moles of ammonium sulfate
h). 10.3 moles of sodium chloride
i). 8.90 moles of carbon dioxide
j). 3.10 moles of diphosphorus pentaoxide
More Mole/Gram Conversions
Include all units.

1.   Calculate the number of moles in 161 grams of zinc.

2.   Convert to grams: 4.93 moles of cobalt.

3.   Convert to moles: 13.7 grams of ammonium sulfate.

4.   Calculate the number of grams in 4.34 moles of cupric chloride.

5.   Find the molar mass of lead (II) acetate.

6.   How many atoms are there in 18.9 grams of chlorine gas?

7.   How many nitrogen atoms are contained in 119 grams of iron (III) nitrate?

8.   What is the mass of 2.10 x 1021 formula units of lead (II) iodide?

9.   What is the mass (in grams) of one molecule of water?

10.   5.40 moles of sodium iodide contains ______formula units and ____atoms.
Stoichiometry
Practice Questions

1.   Sodium carbonate and calcium hydroxide react to form sodium hydroxide and
calcium carbonate. Calculate the mass of each product formed if you are given
20.5g of sodium carbonate.

2.   1K2O + 1H2O  2KOH
If 35.0g of KOH are produced, what mass of K2O was used?

3.   Carbon dioxide and water will produce carbonic acid, H2CO3. 100g of CO2 will produce
_____g of carbonic acid?

4.   Lead (II) nitrate and sodium iodide react by double replacement. If 187g of sodium
iodide is consumed, calculate the mass of each product formed.

5.   ___Na2SO4 + ___BaCl2  __ ____
Complete and balance this equation. Given 100g of Na2SO4 calculate the mass of NaCl
formed.

6.   Zinc reacts with sulfuric acid (H2SO4) to produce hydrogen gas and zinc __________.
Calculate the mass of each reactant if 50g of hydrogen gas is produced.

7.   ___Al + __Cl2  __ ______
What is the product formed? How mass of product will form from 200.5g of aluminum?
More Stoich Problems

1.   A piece of copper wire react in a silver nitrate solution producing silver and copper (II)
nitrate. If 1.46g of silver nitrate are used, how much copper reacts? How much silver
is produced?

2.   Zinc and hydrochloric acid react to produce hydrogen gas. The other produce is zinc
chloride. How zinc is required to produce 2.47g of zinc chloride?

3.   Methane gas mixes with oxygen to produce water and carbon dioxide. How many grams
of each product will be formed 23.6g of methane is available?

4.   Salt, NaCl, can be produced from the reaction between sodium metal and chlorine gas.
How much salt is formed if 5.41g of sodium reacts? How much chlorine is required?

5.   In the manufacture of nitric acid, HNO3, nitrogen dioxide reacts with water as shown
by the unbalanced equation. . .

___NO2 + ___H2O  __HNO3 + __NO

a).   How much nitric acid is produced if 10.0g of NO2 reacts?
b).   How much water is required for the process?
c).   How much NO is produced?
Stoichiometry
Practice Problems (Level 2)

1. When aluminum is heated in oxygen, aluminum oxide is formed. What weight of the
oxide can be obtained from 25.0 g of the metal?

2. When steam (hot water) is passed over iron, hydrogen gas and iron (III) oxide are formed.
What weight of steam would be needed to react completely with 100.0 g of iron?

3. How much ammonium hydroxide is needed to react completely with 75.0 g of copper (II)
(II) nitrate in a double replacement reaction?

4. How much copper metal can be obtained by the single replacement reaction between copper
(I) nitrate and 30.0 g of iron metal? (Iron (II) nitrate is formed.)

5. What weight of sulfuric acid will be needed to react completely with 35.5 g of ammonia
in the production of ammonium sulfate?

6. What weight of chlorine gas will be needed to react completely with 85.8 g of potassium
iodide in a single replacement reaction?

7. In the neutralization reaction between sulfuric acid and potassium hydroxide, how much
potassium sulfate can be produced if you have 150.0 g of sulfuric acid to begin with?
Stoichiometry
Practice Problems (Level 3)

1. How much aluminum metal is needed to replace all of the iron form 27.8 g of iron (III)
oxide?

2. What weight of iron metal will be required to produce 20.8 g of iron (III) oxide in the
reaction with pure oxygen?

3. What weight of aluminum bromide can be produced by the reaction of sufficient aluminum
sulfate with 8.75 g of ammonium bromide?

4. What weights of water and diphosphorus pentoxide will be needed order to produce
95.5 g of phosphoric acid?

5. 50.0 g of oxygen are available for the combustion of 25.0 g of carbon. Is this an adequate
amount of oxygen? If so, by how much in excess is the oxygen? If so, by how much in
excess is the oxygen? If not be how much is the carbon in excess?

6. How many grams of carbon dioxide can be obtained from the reaction of 100.0 g of
sulfuric acid and 100.0 g of calcium carbonate?

7. In testing for the efficiency of an antacid compound, 5.0 g of hydrochloric acid is mixed
with 24.0 g of magnesium hydroxide. Is this enough base to react with all the acid?

8. In the human body, the toxic compound hydrogen cyanide is neutralized by the acid,
H2S2O3, according to the reaction: HCN + H2S2O3 – HCNS + H2SO3. If 1.000 mg of
H2S2O3 is available in the body, will this be enough to neutralize 2.000 mg of HCN
swallowed by a person?
WORKSHEET

1. A piece of copper wire reacts in a silver nitrate solution producing silver and copper (II)
nitrate. If the solution contains 1.46 grams of silver nitrate, how much copper reacts?
How much silver is produced?

2. Zinc and hydrochloric acid react to produce hydrogen gas. The other product is zinc
chloride. How much zince is required to prduce 2.47 grams of zinc chloride.

3. Methane gas mixes with oxygen to produce water and carbon dioxide. How many grams
of each product will be formed if 23.57 grams of methane is available?
CH4 = methane

4. Salt, NaCL can be produced from the reaction between sodium metal and chlorine gas.
How much salt is formed if 5.41 grams of sodium reacts? How much chlorine is required?

5. In the manufacture of nitric acid, HNO3, nitrogen dioxide reacts with water as shown by
this unbalanced equation:

NO2 ÷ H2O  HNO3 ÷ NO

a).    How much nitric acid is produced if 10.0 grams of NO2 react in excess water?
b).    How much water is required for the process.
c).    How much NO is produced?

6. Write a balanced chemical reaction with hydrochloric acid and calcium hydroxide.
Determine the mass of hydrochloric acid needed to produce 10 grams of salt.

7. If 25 grams of manganese (II) oxide is reacted with 75 grams of hydrochloric acid; how
many grams of chlorine gas are produced by the reaction.

(Unbalanced Reaction)

MnO2    +   HCl --- > MnCl2   +   Cl2   +   H 2O

8. How many grams of N2F4 can be prepared from 6 grams of NH3 and 14 grams of F2?
Identify the limiting reactant, excess reactant, and the amount of excess remaining.

Calculate the amount of HF produced.

(Balanced Reaction)

2 NH3 + 5 F2 ----- > 1 N2F4 + 6 HF
Chemistry 20
Finding the Limiting Reagent
***For each reaction, find the limiting reagent***

1.   ___C + __02  __C O2

a).    5.2 moles of C, 8.4 moles of O2
b).   12.1 moles of C, 1.21 moles of O2
c).   18.5g of C, 24.2g of O2
d).   8.8g of C, 88g of O2

2.   ___Al + __O2  __Al2O3

a).   6 moles Al, 4 moles O2
b).   19.3 moles Al, 8.1 moles O2
c).    27.0 moles Al, 23.8 moles O2
d).   17g Al, 3.0g 02
e).    183g Al, 76.2g O2

3.   __H2 + __N2  __NH3

a).   4 moles N2, 5 moles H2
b).   17 moles H2, 6.4 moles N2
c).   12.3g H2, 18.3g N2
d).   1953g H2, 4321g N2
e).   0.000273g H2, 0.000442g N2

4.   __H2S + __O2  __SO2 + __H20

a).   3.4 moles O2, 2.1 moles
b).   17.32 moles H2S, 12.98 moles O2
c).   18.3g O2, 45.2g O2
d).   73g H2S, 95g O2
Using the Limiting Reagent

1.   __C + O2  __CO2 18.5g of C reacts with 24.2g of O2

a)    Which reactant is the limiting reagent?
b)    Find the mass of CO2 produced
c)    Find the mass of C that reacts
d)    Find the mass of C that remains

2.   __Al + __O2  __Al2O3 183g of Al, 76.2g of O2

a).   Which reactant is in excess?
b).   Find the mass of Al2O3 produced
c).   Find the mass of excess reagent that reacts
d).   Find the mass of excess reagent that remains
e).   Find the mass of excess reagent that remains

3.   __H2 + __N2  __NH3 1953g of H2, 321g of N2

a).   Which is the limiting reagent?
b).   What mass of NH3 is produced?
c).   What mass of N2 reacts?
d).   What mass of N2 remains?

4.   __H2S + __O2  ___SO2 + __H2O 18.3g of O2, 45.2g H2S

a).   Find the limiting reagent
b).   What mass of SO2 is produced?
c).   Find the mass of water produced
d).   How many grams of excess reagent remains?
Limiting Reagents

1. When hydrogen gas reacts with chlorine gas, hydrogen monochloride (also called
hydrochloric acid) is produced. If 0.45g of hydrogen and 20g of chlorine react,
answer the following. . . .

a). Write a balanced equation for this reaction.

b). Find the limiting reagent

c). How many moles of HCI would be produced?

d). What mass of excess reactant reacts?

e). Find the mass of excess reagent remaining.

2. When 20g of silver nitrate reacts with 20g of copper, copper (II) nitrate and silver
are produced.

a). Write a balanced equation for this reaction.

b). Find the limiting reagent

c). What mass of silver would be produced?

d). What mass of excess reactant remains?

e). Find the total mass of the products in the reaction.
Limiting Reagents II

1.   15 moles   20g
__HCl + __NaOH  __H2O + __ NaCl

a). Finding the limiting reagent

b). What mass of water is produced?

c). What mass of excess reactant remains?

2.   3.0g   10g        x grams
__ CH4 + __O2  __ ___ + __ H2O

a).   Find the limiting reagent

b).   Solve for x

c).   What mass of excess reactant remains?

3.   15g of hydrogen gas reacts with 4.0 moles of iodine gas.

a).   Write a balanced equation

b).   Find the limiting reagent

c).   What mass of Hl is produced?

d).   What mass of excess reactant remains?
Stoichiometry Review

1. Write the formulas for the following compounds. . . .
a). sodium oxide ___________            b). aluminum chloride ________________
c). iron (ll) nitride __________        d). calcium carbonate ________________
e). copper (l) oxide _________          f). ammonium phosphate _______________
g). lead (IV) iodide _________          h). potassium permanganate ____________
i). iron (lll) chloride _________       j). hydrogen hydroxide ________________

2. For each of the following compounds, find the molar mass (in grams)
a). sodium oxide ___________             b). aluminum chloride ________________
c). iron (ll) nitride __________         d). calcium carbonate ________________
e). copper           ___________         f). ammonium phosphate _______________
g). lead (lV) iodide __________          h). potassium permanganate ____________
i). iron (lll) chloride _________        j). hydrogen hydroxide _______________

3.   Convert the following…..
a). 4.5 mol Fe into atoms

b). 4.57 x 1025 atoms into molecules H2O

c). 9.54 mol iron (lll) oxide into grams

d). 2.00 mol silver nitrate into atoms

e). 50g C3H8 into atoms

4.   List the 5 reaction types and describe how each may be identified.

a).

b).

c).

d).

e).
5.   Identify the following reaction types and balance………
a).   __Na + __l2  __ Nal                              ________________________

b).    __N2 + __O2  __ N20                             ________________________

c).    __N2 +   ___H2    __ NH3                        ________________________

d).   __Kl + __Cl2  __KCl + __l2                       ________________________

e).   __HCl + __Ca(OH)2  __CaCl2 + __HOH               ________________________

f).   __S + __ O2  __SO3                               ________________________

g).   __H2O2  __ H2O + __ O2                           ________________________

h).   __CH4 + __O2  __ CO2 + __ H2O           ________________________

6.   Complete the following reactions and balance

a). __Al + __ l2           __ _________

b). __CaSO4 + __BaBr2               __ _________ + __ _________

c). __C3H3 + __ O2                    __ _________ + __ _________

d). __NaCl                            __ _________ + __ _________

e). __F2 + __Al2O3                    __ _________ + __ _________

7.   15g of barium bromide react with 35g of sodium carbonate
a), What type of reaction is this? __________________________
b). Write a balanced equation for the reaction.

c). Which is the limiting reagent?

d). What mass of excess reagent remains?

e). Find the mass of each product.
Reaction Types Practice

For each reaction given, predict the products and write a complete, balanced equation.

Combination
a).    calcium reacts with bromine

b).    magnesium and nitrogen react

c).    carbon dioxide reacts with water

Decomposition
d).    hydrogen peroxide breaks down into water and oxygen

e).    magnesium chlorate decomposes into magnesium chloride and ????

f).    hydrogen iodide decomposes

Single Replacement (Check to see if reaction occurs . . . 7-5)
g).   zinc and lead (IV) nitrate react

h).   fluorine reacts with aluminum chloride

i).   iron (II) reacts with water

j).   calcium nitride and oxygen react
Double Replacement
k).   calcium chloride reacts with hydrogen sulfide

l).   ammonium acetate reacts with aluminum carbonate

m).   iron (III) nitrite reacts with copper (II) hydroxide react

n).   hydrogen phosphate and calcium hydroxide react

o).   barium chloride and hydrogen sulfate react

Combustion
p).   decane (C10H22) burns

q).   ethanoic acid (CH3COOH) burns

r).   sucrose (C12H22O11) burns

s).   methanol (CH3OH) reacts with oxygen
Lab Guidelines

1. Labs are very important documents. They are similar to essays in social studies or English
classes. You lab should follow all the rules of good grammar, spelling, punctuation, and so
forth. It should be neat and orderly. Generally speaking, the lab should be a representation
of your best work.

2. Each lab has a title page. The title, your name, your partners name, and the date go on this
page. Nothing else belongs on this page of your lab.

3. In the body of the lab, the following headings should be clearly presented in a neat fashion:

4. The purpose, often called the problem or objective, is a description of what you are
attempting to do or find out in the lab. It should be no longer than 2 or 3 sentences at most.
Most often, it can be stated as single sentence. You may copy the purpose from a book if you
wish, or you may express it in your own terms.

5. The materials section simply lists the materials used in the lab, and can often be found in the
text you are working from. This section need not be presented in sentence form. You may
simply list the materials, or, if you wish, you may draw a diagram provided it includes all the
materials you use.

6. The procedure is the recipe or list of steps to follow to perform the experiment. If the lab
is from a text or handout, you may refer to it by title and page number in your procedure
instead of rewriting it. If the procedure is not from a text or handout, you must copy the
procedure into your lab. The steps of a procedure must be numbered.

7. The data section of every experiment contains the information you gained by performing the
lab. It is best if all data is presented in a table format.

8. If the procedure asks you to draw a graph, put the graph in the analysis section of your lab.
Sample calculations may also be included to show how values have been calculated in order to
complete your data table. An analysis of the percent error or the percent difference is also
expected in this section where possible. All questions asked in the procedure should be
answered in this section. If no graph, percent error/difference or questions are required in
the procedure/instructions, then you can omit the analysis section of your lab. (NOTE: for
graphs in this section, most people simply state, see attached graph(s).)

9. The conclusion section should be no longer than a paragraph explaining your answer to the
purpose.

10. The Sources of Error section should be no longer than a paragraph, outlining the reasons for
your results not matching up with the expected values. In general, comment on the value you
arrived at in determining your percent error, and gives reasons to justify this value.
11. The question section should contain the questions and their corresponding answers. Many
times only some questions are required.
STOICH LAB                                                     Name: _______________
Partner: ______________
Date: ________________

Purpose:
In this experiment, you will investigate the reaction between solutions of lead nitrate and
potassium iodide. This is a ________ ______________ reaction where one of the products is
a solid precipitate. Stoichiometry calculations will be done in order to determine masses of
product formed. Please measure accurately!

Equation:

Procedure:

1.    Find the molar masses of all reactants and products.
2.    Weigh a clean, dry, 150 mL beaker. Add 1 – 1.5 g KI. Weigh again.
3.    Determine number of moles of KI.
4.    Calculate the number of moles of Pb(NO3)2 required to react with all of the KI. Convert
this to grams.
5.    Have your answer checked. Then weigh out the amount into another clean, dry, 150 mL
beaker.
6.    Add approximately 25 mL purified H2O to each beaker of solid. Stir.
7.    Pour the lead nitrate solution into the potassium iodide solution, rinse the beaker with 5
mL of H20 and add to the mixture. Cover. Leave in a safe place.
8.    Fold a piece of filter paper. Weigh it. Place it in a funnel. Wet it with distilled H20. Set
it over a beaker.
9.    Decant the liquid from the reaction beaker into the filter paper. Leave as much of the
solid as possible in the beaker. Wash the solid with approximate 5 mL H2O. Let the solid
settle, then decant the washing water and filter it. Wash and decant again. Do not
attempt to wash the ppt. into the filter. When the filtering is complete, remove the filter
paper and place in the beaker with ppt. Save the filtrate for the next step. Dry the ppt.
as directed.
10.    Weigh a clean, dry, evaporating dish. Pour in some of the filtrate. Heat gently. Continue
adding the filtrate until it is all in the dish. Continue heating until it is dry. Do not
overheat. Cool. Weigh it.
11.    When the ppt is dry, weight it.

Data: Be organized! Include units!! Make a neat data table in pen.

Calculations:
1.      Find the mass of each product actually formed.
2.      Calculate the mass of each product that should have formed.
3.      For each product; calculate % error
% error = theoretical – actual x 100
theoretical
4.      Describe the properties of each product.
5.      Was the Law of Conservation of Mass obeyed in the experiment? Explain. Show a
calculation.

Conclusion:   (on looseleaf)
Stoichiometry:                                             Name:                   Date:
Partner:                Station:

IRON-COPPER II CHLORIDE REACTION

In this experiment you will let iron nails react with a copper chloride solution. After
observing the results of this chemical reaction, you will determine which salt, iron (II) chloride,
or Iron (III) chloride is formed.
As you do the experiment, record your observations and data accurately and neatly. Take
special care to record the units as an important part of each measurement.
Before coming to the laboratory, plan what read the procedure and make suitable data
table.

PROCEDURE:

A.      Find the mass of a clean dry labeled 150 mL beaker.
B.      Measure approximately 4 grams of copper (II) chloride crystals. Record this mass.
C.      Add about 30 mL distilled water to the crystals in the beaker. Stir the mixture until all
the crystals are dissolved.
D.      Obtain 2 clean, dry iron nails. Polish the nails with steel wool to remove any rust or
protective coating.
E.      Weigh the nails together and record their total mass to the nearest 0.01 gram.
F.      Place the nails in the copper (II) chloride solution and let the reaction proceed for about
20 minutes. Record the beginning and ending times.
G.      Remove the nails, one at a time, with a pair of tongs. Using a wash bottle, wash all the
reddish-brow; material from the nails into the beaker. Describe the properties of this
solid and identify it.
H.      Dip the nails in acetone, and let them dry, then weigh them to determine their combined
mass. Record this mass to the nearest 0.01 gram.
I.      Carefully decant the solution and put it in the waste container provided.
J.      Wash the remaining solid with about 25 mL of distilled water and decant. Repeat the
washing an decanting procedure 4 or 5 times. Lose as little of the solid as possible.
K.      Nest, wash the copper with about 25 mL of 1 M HCl solution. Decant and wash again with
distilled water, dry and weight the copper.
Calculations: Show neatly. Be organized. Include units, show formulas used.

1. Find the mass of iron that reacted.

2. There are two possible reactions in this experiment (a) The iron can form iron (II) chloride or
(b). The iron can form iron (III) chloride. Write the balanced equation describing each
reaction.

3. Using stoichiometry find the mass of copper that should form for each reaction.

4. a).   Find the mass of copper that formed.
b).   Tell which equation describes your reaction. Justify your answer.

5. Calculate the % error in your experiment.

6. Using stoichiometry (be sure to use the correct equation) calculate the mass or iron chloride
salt that formed. Explain where this salt was at the end of the reaction.

7. a).   Calculate the mass of copper (II) chloride used.
b).   Find the mass of copper (II) chloride left at the end of the experiment. Where was this
salt? What observation confirms this?
CARBONATES AND ACIDS

Name: ___________
Date: _____________
Class: _____________
Period: ____________
Partner: ___________

In grade 10 you learned that acids react with carbonates to produce carbon dioxide
and water. In this experiment you will study this reaction quantitatively using a solution of 2.0
M HCl and calcium carbonate in the form of marble chips.

Purpose:      To study the reaction quantitatively, determining mass, moles and volume of the
reactants and products.

Equation:

Procedure:    1. Obtain a 125 ml Erlenmeyer flask and find its mass.
2. Add 25.0 ml of 2.0 M HCl to the flask and find the total mass.
3. Obtain 1.5 – 2.0 g of marble chips using a filter paper. Record the amount
obtained.
4. Do the Theory Section Calculations and predict the amount of each product
produced.
5. Show your “Theory Section Calculation” to your teacher. Have them
initialed!!!
6. Add the chips to the acid and observe the reaction. Record the mass of the
products(s).
7. When the reaction is over find the mass of the flask and products. Record
the mass of the product(s).
8. Discard the contents of the flask in the sink with plenty of water.
9. Calculate % Error for the gas produced. Discuss this value in your
conclusion.

Data:             Devise your own data table.
Calculations and Questions:

SHOW WORK FOR ALL CALCULATIONS

Theory Section Calculations

A.   Using stoichiometry calculate:

1.   Which reactant is entirely consumed during the reaction (limiting reactant)

2.   The expected mass of each product.

Experimental Section Calculations

1.   Find the mass of the reaction flask and the reactants.

2.   Calculate the number of moles of calcium carbonate chips in the reaction flask.

3.   Calculate the number of moles of hydrochloric acid in the reaction flask.
Remember HCl is a solution.

4.   Explain why the flask was lighter after the reaction.

5.   Find the mass of the gas.

Additional Calculations

6.   Calculate the % Error for the gas.

7.   Using stoichiometry calculate the volume (at STF) of the gas.

8.   Write a conclusion

9.   Discuss the several ways to find moles that were used in this experiment.
LIMITING STOICHIOMETRY

1.   Iron burns in air to form a black solid oxide, Fe3O4.

a).   Write the balanced equation.
b).   If one had 50.0g of iron and 60.0g of oxygen, which reactant is the limiting
reactant?
c).   How much Fe3O4 is produced (grams)?

2.   Hydrogen and oxygen react to form water.

a).   Write the balanced equation.
b).   If one had 7.0g O2 and 1.0g H2, how much water will be formed?
c).   How many moles of the excess reactant are left?
d).   How many grams of the excess reactant are left?

3.   Sodium carbonate is needed in the manufacture of glass, but very little occurs
naturally. It is made in the following way.

CaCO3 + NaCl  Na2CO3 + CaCl2

a).   Balance the equation.
b).   If one has 5.0g of each reactant, how much Na2CO3 will be formed?
Using Moles: Finding the Formula of a Hydrated Compound.

Theory:        Some compounds store water molecules as part of their crystal structure. The
water is actually a part of the compound as you weigh it. An example is cobalt
chloride hexahydrate. This ionic compound contains 6 moles of H2O for every
mole of CoCl2 in the compound. The formula is shown CoCl2. 6H2O where the
dot means 6 moles H2O attached to one mole of CoCl2.

Purpose:       Find the formula of bluestone. [Bluestone is copper (II) sulfate with water
molecules attached CuSO4 .xH2O].

Procedure:     1. Weight a clean dry evaporating dish.
2. Place about 3-5g of bluestone crystals in the evaporating dish. Record the
properties of bluestone.

Caution Goggles
3. Heat the dish strongly until anhydrous copper sulfate remains. Record the
properties of the anhydrous salt.
4. Let the dish cool until you can pick it up with your fingers. Then weigh again.
5. Do your calculations before discarding the salt. If necessary heat and cool
again.

Data: Collect in pen in a neat table.

Calculations: Show neatly. Identify each.
1. Find the mass of anhydrous copper II sulfate.
2. Find the mass of water lost.
3. Find the moles of salt.
4. Find the moles of water.
5. Find the ratio of moles H20 per 1 mole salt.

Write a conclusion and a discussion.
Chemistry 30S Review
Stoichiometry & Equations

1.   Find the molar mass of Al(HSO4)3.

2.   Find the mass of:
a). 0.850 moles of Fe(NO3)3.
b). 2.40 x 1022 molecules of K2CO3.
c). 7.48 x 1024 atoms of Ca.

3.   How many molecules are there in?
a). 54.30 grams of baking soda, NaHCO3.
b). 1.24 moles of water, H20.

4.   How many atoms are there in?
a). 8.160 grams of table salt, NaCl.
b). 3.64 x 1023 molecules of Sr(ClO3)2.

5.   How many dm3 of oxygen are in 16.2 moles of O2 at S.T.P.?

6.   Butane gas burns as follows at S.T.P.
2C4H10 + 1302  8CO2 + 10H20

a).   How many moles water are formed?
b).   How many dm3 butane burned?
c).   How many dm3 carbon dioxide produced?
d).   What mass in grams of     used up?

7.   Given: 2C2H6 + 702  4CO2 + 6H20 at S.T.P.
a). What mass of oxygen is needed to react with 68.25 grams of ethane, C2H6?
b). How many molecules of carbon dioxide will form when 3.24 moles of ethane reacts
with oxygen?
c). How many moles of water can be made from 35.00 grams of ethane?
d). What volume of CO2 at S.T.P will be produced from 45g of C2H6?

8.   Given: 4NH3 + 702  4NO2 + 6H20
a). What mass of oxygen is needed to burn 74.50 grams of ammonia, NH3?
b). How many moles of water will form when 38.25 grams of ammonia is burned?
c). How many moles of oxygen gas are needed to produce 3.57 moles of NO2?
d). When 27.50 grams of ammonia is burned, how many molecules of water form?
e). How many moles of water can be made from 2.75 x 1023 molecules of ammonia?
f). If 4 moles of NH3 and 3.5 moles of O2 are reacted, how many moles of H20 are
produced.
g).   38.0 g of NH3 reacted with 160 g of O2; what mass in grams of NO2 is formed?
h).   55.5 g of NH3 reacts with 112 dm3 02; what volume of NO2 is produced?
i).   85.6 dm3 of NH3 is burned in 208 g of oxygen; what mass of water is collected?

9.   Copper reacts with hydrochloric acid to produce copper chloride and hydrogen. If 3.2
grams of copper produces 6.8 grams of copper chloride when reacted with an excess of
hydrochloric acid, determine whether CuCl2 was produced.
Equations

Balance the following equations. Also state what type of reaction each is for all questions on
this page.

1.    NaOH + H2SO4  Na2SO4 + H2O

2.    H2 + Cl2  HCl

3.    Zn + HCl  ZnCl2 + H2

4.    CaCO3 + HCl  CaCl2 + CO2 + H20

5.    KCl + AgNO3  H3PO4 + H20

6.    KCl + AgNO3  KNO3 + AgCl

7.    Zn0 + HCl  ZnCl2 + H20

8.    FeCl3 + Fe  FeCl2

9.    Zn + Na0H  NaOH  Zn(0H)2 + Na

10.    H2S + S02  H20 + S

Write formulas for the word equation and balance it.

1. Sulphuric acid + ammonium hydroxide  ammonium sulfphate + water

2. Potassium hydroxide + hydrochloric acid  potassium chloride + water.

3. Potassium bromide + chlorine  potassium chloride + bromine

4. Calcium oxide + water  calcium hydroxide

5. Calcium chloride  calcium + chlorine

6. Zinc + sulphuric acid  zinc sulphate + hydrogen

7. Lithium iodide + bromine  lithium bromide + iodine
8. Aluminum + sulphuric acid  aluminum sulphate + hydrogen

9. Magnesium + oxygen 

10. Iron + oxygen Iron III oxide

11. Calcium carbonate + hydrochloric acid  calcium chloride + water + carbon dioxide.

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