Name
Seat
Date
Pd
Unit 8, Mole Ratios
For each of the problems below:
a. Write the balanced chemical equation.
b. Identify what is given (with units) and what you want to find (with units).
c. Use coefficients from balanced equation to determine mole ratio.
d. Show set up (organize it!) and complete the BCA table
1. Lead will react with hydrochloric acid to produce lead (II) chloride and hydrogen
gas. How many moles of hydrochloric acid are needed to completely react with 4.0
mole of lead?
Equation:
Pb + HCl 
PbCl2 +
H2
Before
Change
After
2. How many moles of hydrogen gas will be produced if 2.5 moles of calcium hydride
react according to the following equation?
CaH2 + 2 H2O  Ca(OH)2 + 2 H2
Before
Change
After
3. How many moles of water will be produced if 0.45 mol of oxygen reacts according
to the following equation?
2 C6H6 + 15 O2  12 CO2 + 6 H2O
Before
Change
After
Modeling Chemistry
1
U8 BCA overhead v2.0
Unit 8 Worksheet 1: Mole relationships
1. Hydrogen sulfide gas, which smells like rotten eggs, burns in air to produce sulfur dioxide
and water. How many moles of oxygen gas would be needed to completely burn 8 moles of
hydrogen sulfide?
Equation:
___ H2S + ___ O2  ___ SO2 + ___ H2O
Before
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___
Change
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After
2. Propane, C3H8, burns in air to form carbon dioxide and water. If 12 moles of carbon
dioxide are formed, how many moles of propane were burned?
Equation: ___C3H8 + ___O2 
___CO2 + ___H2O
Before
Change
After
3. Ammonia, NH3, for fertilizer is made by causing hydrogen and nitrogen to react at high
temperature and pressure. How many grams of ammonia can be made from 2.55 grams
of nitrogen gas?
Equation:
___ N2 + ___ H2  ___ NH3
Before
Change
After
Modeling Chemistry
2
U8 BCA overhead v2.0