Name: _____________________________
Per:______
Date:__________
WS 9-1: The Stoichiometry & Balanced Chemical Reactions
Completion: Complete the following sentences by filling in the appropriate word or phrase from the list
below. Each word or phrase may be used once, more than once, or not at all.
reactants
particles
actual
subscripts
coefficients
quantitative
conservation of matter
mass
molar ratio
Molar
1. Stoichiometry is the study of the ______________________________ relationships that exist in
chemical reactions.
2. Stoichiometry can be used to determine how much product will form from a given amount of
__________________________.
3. The ____________________________ in a balanced equation indicate(s) the number of particles of
each substance taking place in the reaction.
4. A balanced equation verifies the Law of ____________________________________________.
True & False: If the statement is true, write “true.” If it is false, change the underlined word or words to
make the statement true. Write your answer on the line provided.
__________________9. You can determine the number of moles of any substance produced in a reaction
if you know the number of moles of at least two of the reactants.
__________________ 10. The molar ratio of hydrogen to oxygen in the equation
2H2 + O2 → 2H2O is 1:2.
__________________11. The total mass of the reactants is equal to the total mass of the products in a
chemical reaction.
__________________12. Mole-mole problems involve conversions from moles of one substance to
mass of another.
Problems: Solve each of the following problems as directed. Show all your work.
13. How many moles of magnesium are required to react 2.0 mol of hydrochloric acid in a single
replacement reaction? Write the balanced equation and solve the problem.
Mg +
HCl 

Balance the Equation:
H2 +

Determine the molar ratio: ______mol Mg : ______mol HCl

Solve Using Dimensional analyses:
MgCl2
14. Aluminum reacts with hydrochloric acid to produce in a single replacement reaction. Write the
balanced equation for this reaction and calculate the number of moles of hydrochloric acid required to
react with 0.87 mol of Al.
Al +
HCl 

Balance the Equation:

Determine the molar ratio: ______ : ______

Solve Using Dimensional analyses:
AlCl3 +
H2
15. Glucose (C6H12O6) combines with oxygen gas in the body in a combustion reaction write the balanced
equation for this reaction. How many moles of oxygen gas are required to combine with 0.25 mol of
glucose? How many moles of carbon dioxide gas and water would be produced by this reaction?

Balance the Equation:

Determine the molar ratio:

Solve Using Dimensional analyses:
C6H12O6 +
O2 
CO2 +
H2O
17. One molecule in a barium chloride solution reacts with one molecule in a sodium sulfate solution to
produce 1 molecule of solid barium sulfate and 2 molecules of sodium chloride in solution. How many
moles of BaCl2 are needed to produce 4 moles of sodium chloride?

Balance the Equation:

Determine the molar ratio:

Solve Using Dimensional analyses:
18. Two molecule of solid potassium chlorate, when heated, decompose into two molecules of solid
potassium chloride and 3 molecules of oxygen gas (O2). If you want to generate 9 moles of Oxygen
gas?
19. Two molecules of solid sodium chloride decompose when exposed to an electric current into two atoms
of sodium metal and 1 molecule of chlorine gas (Cl2). How many moles of sodium metal will be
produced if 3 moles of sodium chloride are reacted?