`Name ____________________________________Period _____Date ___________Code# ___________
Calculating Quantities in Reactions
Complete each statement below by writing the correct term or phrase for question 1-8.
1. All stoichiometric calculations involving equations Word list:
2. When solving stoichiometric problems, you
must________________________ the equation first. density
3. Balanced equations give the________________________ numbers of moles
4. ________________________in chemical equations provide mole ratios that molar mass
can be used as conversion factors.
5. The conversion factor for converting between mass and moles is
the________________________ of the substance. relative
6. In making calculations involving ________________________, you must
convert volume to mass.
7. To convert from volume to mass, you can use the mole
________________________of the substance as the conversion factor.
8. When calculating the number of particles, you can use
________________________as the conversion factor.
For problems 9-13, write the letter of the choice that best completes the statement or answers the question.
Consider the following problem when answering:
What mass of sulfuric acid is required to neutralize 2.65 g of potassium hydroxide? The products of the
reaction are potassium sulfate and water.
______ 9. What should you do first after reading ______12. What should you round off?
the problem carefully? a. the result of each step
a. Estimate the answer. b. all data values
b. Calculate the molar mass of sulfuric acid. c. only the final answer
c. Write a balanced chemical equation. d. nothing
d. Convert all masses to moles.
______13. Which of the following is least likely
______10. What should you do before setting up to help you verify the final result?
the problem? a. estimating the answer by using rounded
a. Determine the densities. numbers
b. Calculate molar masses. b. determining whether the answer is
c. Convert all masses to moles. reasonable for the conditions of the
d. Estimate the answer. problem
c. rechecking all molar masses
______11. How should you check your setup? d. writing a balanced chemical equation
a. by recalculating molar masses
b. by checking to see if the result will have
the correct units(dimensional analysis)
c. by estimating the answer
d. by writing a balanced chemical equation
As extra practice you can try balancing the equations on the next problems. Just re-write the equation
without the coefficients and re-balance.
Answer the following items in the space provided.
14. Determine the number of grams of phosphorus formed for each 1.00 g of Ca3(PO4)2 used in the
production of phosphorus in an electric furnace.
Ca3(PO4)2(s) + 3SiO2(s) + 5C(s) 3CaSiO3(s) + 5CO(g) + 2P(s)
15. How many grams of aluminum chloride are produced when 18 g of aluminum are reacted with an excess
of hydrochloric acid?
2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g)
16. How many grams of ethanol, C2H5OH, can be made by the fermentation of 1150 g of glucose, C6H12O6?
C6H12O6(l) 2C2H5OH(l) + 2CO2(g)
17. How many moles of oxygen are required for the combustion of 25.5 g of magnesium?
2Mg(s) + O2(g) 2MgO(s)
18. How many grams of CO2 are produced from the burning of 1.0 mol of amyl alcohol?
2C5H11OH(l) + 15O2(g) 10CO2(g) + 12H2O(g)
19. How many moles of nitromethane are needed to form 500.0 g of chloropicrin, CCl3NO2, a chemical
used in the production of insecticides?
CH3NO2(l) + 3Cl2(g) CCl3NO2(l) + 3HCl(g)
STARTING HERE, THESE PROBLEMS REQUIRE AN EXTRA STEP(S)
20. How many liters of oxygen are produced from the decomposition of 122 g of potassium chlorate? The
density of oxygen is 1.33 g/L.
2KClO3(s) 2KCl(s) + 3O2(g)
21. How many grams of potassium chloride are formed by the decomposition of sufficient potassium
chlorate to yield 3.4 L of oxygen? Remember that the density of oxygen is 1.33 g/L.
2KClO3(s) 2KCl(s) + 3O2(g)
22. How many liters of phosphine gas are produced when 910 g of calcium phosphide react with water? The
density of phosphine gas is 1.517 g/L.
Ca3P2(s) + 6H2O(l) 3Ca(OH)2(s) + 2PH3(g)
23. How many grams of air are required to complete the combustion of 93 g of phosphorus to diphosphorus
pentoxide, assuming the air to be 23% oxygen by mass?
4P(s) + 5O2(g) 2P2O5(s)
24. How many metric tons of carbon dioxide can be produced from the combustion of 5.00 metric tons of
coke that is 85.5% carbon?
C(s) + O2(g) CO2(g)
25. If 100. mL of carbon disulfide (density=1.26 g/mL) is burned completely, how many liters of SO2 and of
CO2 are formed?
CS2(l) + 3O2(g) CO2(g) + 2SO2(g)