# Practice Exam 1 - Get as DOC by 0Ccf04c

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Practice Exam 1 – 100 points
Chapters 1 - 4
75 minute Exam

Multiple Choice: (2 pts each) Carefully read and deduce or calculate (as needed) the best
answer. Indicate your choice in the blank provided. There is only one correct answer unless
stated otherwise.

_____1. Which of the following is a set of isotopes?
A) 24 Cr 2 , 24 Cr 3, 24 Cr 4 
52          52        52

B) 12C 4 – , 12C, 12C 4 
6         6      6
40       43       44
C) 20 Ca, 20 Ca, 20 Ca
   D) 113Cd, 113In, 113Sn
48        49       50

   E) all sets are isotopes
F) none of the sets are isotopes

   _____2. The molar mass of Ni3(PO4)2 is (g/mol):
A) 105.66                            B) 153.66                              C) 271.04
D) 302.01                            E) 303.04                              F) 334.01
G) 335.04                            H) 366.01

_____3. Which of the following has three significant figures? State all that apply.
A) 0.67              B) 0.0300              C) 0.004
D) 2.54 cm/in        E) 270                 F) all have 3 sig figs

_____4. These three equations describe an oxidation-reduction method for determining dissolved
oxygen in water. How many moles of S2O32¯ are equivalent of each mole of O2?
1) 2Mn2+(aq) + 4OH¯(aq) + O2(g) ---> 2MnO2(s) + 2H2O(l)
2) MnO2(s) + 2I¯(aq) + 4H+(aq) ---> Mn2+(aq) + I2(aq) + 2H2O(l)
3) 2S2O32¯(aq) + I2(aq) ---> S4O62¯(aq) + 2I¯(aq)
A) 4 mol      B) 2 mol      C) 1 mol        D) 0.5 mol

_____5. A dilute HCl solution is to be prepared from a more concentrated solution. Which of
pieces of glassware will give the highest level of precision?
A) pipet and graduated cylinder
B) two graduated cylinders
C) pipet and volumetric flask

_____6. Calculate the percent by mass of hydrogen in diethylamine, (C2H5)2NH.
A) 11.3%
B) 13.7%
C) 15.2%
D) 23.6
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______7. Given an HNO3 sample containing 6.02 x 1023 atoms of O. How many moles
of HNO3 are in the sample?
A) 0.20 moles      B) 0.33 moles     C)1mole    D)3 moles      E) 5 moles
F) not enough information to determine

_____8. Given the reaction: 6 Li (s) + N2 (g) ––––> 2 Li3N (s)
Given that 0.50 moles of Li3N (s) are produced, how many moles of Li (s) would be
needed? Assume excess nitrogen.
A) 0.33 mols                 B) 0.67 mols             C) 0.50 mols              D) 1.0 mols
E) 1.5 mols                  F) 4.0 mols              G) 6.0 mols               H) 12 mols

_____9. Calculate the density of a gold coin from the given data.
Table of Data
Mass of the gold coin               13.5243 g
Volume of the coin and water        22.90 mL
Volume of the water alone           22.20 mL
A) 19.32 g/mL
B) 19.3 g/mL
C) 19 g/mL
D) 2 x 101 g/mL

_____10. Which of the following has a molecular formula that is also the empirical
formula?
A) Na2C2O4         B) P2O10      C) C4H10 D) Hg2(NO3)2             E) C2H4O
F) none of these

_____11. Each of three samples was weighed on a different balance. The masses of the
three are 1.028 kg, 82.9 g, and 45.1 mg. The sum of the three masses should be reported
as
A) 1.11 x 103 g        B) 1110.9451 g        C) 1111 g             D) 110 g

_____12. Which pair of substances could be used to illustrate the law of multiple
proportions?
A) SO3 and H2SO4
B) CO and CO2
C) Fe2+ and Fe3+
D) CH2O and C6H12O6
E) Chlorine-35 and chlorine-37

13.(4 pts) Calculate and report the final answer to the correct number of significant
figures.
A) 27.2 + 1.80 = ____________           B) (6.84 x 105 )/ 4273 = ______________
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14. (6 pts) Balance the following redox reaction in acidic conditions.
H2O2 + MnO4-  O2 + Mn2+

For the above reaction ___________ is the element oxidized, and _________________
is the oxidizing agent.

15. (8 pts) A 1.42 g sample of a pure compound, with formula M2SO4, was dissolved in
water and treated with an excess of aqueous barium chloride, resulting in the precipitation
of all the sulfate ion as barium sulfate. The precipitate was collected, dried, and found to
weigh 2.33 g. Determine the atomic mass of M, and identify M.

16. (6 pts) A compound contains only carbon, hydrogen, nitrogen, and oxygen.
Combustion of 0.157 g of the compound produced 0.213 g CO2 and 0.0310 g of H2O. In
another experiment, it is found that 0.103 g of the compound produced 0.0230 g of NH3.
What is the empirical formula of the compound?
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17. (4 pts) When FeCl3 is ignited in an atmosphere of pure oxygen, this reaction takes
place.
4 FeCl3(s) + 3 O2(g)  2 Fe2O3(s) + 6 Cl2(g)
If 3.4 mol of FeCl3 are ignited in the presence of 2.2 mol of O2 gas, how much (in moles)
of which reagent is present in excess and therefore remains unreacted?

18. (8 pts) What mass (in grams) of carbon dioxide is collected when 300.0 mL of 0.200
M sodium bicarbonate is added to 200.0 mL of 0.15 M citric acid, H3C6H5O7?
____ NaHCO3 + _1_ H3C6H5O7 ––> ____ CO2 + ___ H2O + _1_ Na3C6H5O7
(unbalanced)

19. (8 pts) An alloy used in aircraft structures consists of 93.7 % Al and 6.3 % Cu by
mass. The alloy has a density of 2.85 g/cm3. A 0.691 cm3 piece of the alloy reacts with
excess HCl(aq). If we assume than all of the Al but none of the Cu reacts with
hydrochloric acid, what is the mass of H2 obtained? The reaction of Al with the acid is
given below:
2 Al (s) + 6 HCl (aq) → 2 AlCl3(aq) + 3H2(g)
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Nomenclature and Net Ionic Equations

20. (6 pts) A) Convert the following description into a balanced chemical (molecular)
equation:
When solutions of calcium chloride and sodium phosphate are mixed, solid calcium
phosphate forms and sodium chloride remains in solution.

B) Draw in the beaker below the ions and compound present after the reaction occurs.

21. (6 pts) 1. Name the following compounds

A. P2O4               ____________________________

B. H2SO3              ____________________________

C. H2S (aq)           ____________________________

D. NaBrO3             ____________________________

E. SnF4               ____________________________

F. Cu(H2PO4)2         ____________________________
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22. (6 pts) Write formulas for the following compounds

A. lead(IV) carbonate                 ____________

B. dinitrogen pentoxide               ____________

C. nitrous acid                       ____________

D. mercury(I) acetate                 ____________

E. ammonium dichromate                ____________

F. barium hydrogen sulfate            ____________

23. (6 pts) For the following reactions, clearly predict the products and balance the
molecular equation. Show the complete Net Ionic Equation on the indicated line and
show all physical states in parenthesis.
A) ___ FeCl3+ ___ NH3 + ___H2O ––––>
NIE:

________________________________________________________________________

B) _____ Ag3PO4         + _____ HNO3        ––––>
NIE:

________________________________________________________________________

(6) 24. (6 pts) Write balanced net ionic equations for the following reactions. Show all
physical states in parenthesis.

A. aqueous copper(II) chloride and aqueous potassium hydroxide

B. aqueous hydrochloric acid and aqueous sodium nitrite

C. aqueous ammonia and hydrofluoric acid

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