Stoichiometry Worksheet 2: Percent Yield
RCC.2:
RCC.3:
I can use a balanced chemical equation and BCA chart to determine the amount (either grams
or moles) of reactant used or product produced given a beginning amount (mole or grams) of
reactant or product.
I can use a balanced equation and a BCA chart to determine the theoretical yield of a reaction
and the percent yield of a reaction.
For each of the problems below:
a. Write the balanced chemical equation.
b. Identify the given (with units) and what you want to find (with units).
c. Show set up with units. Check sig figs, give final answer with units and label.
1. Using the Hoffman apparatus for electrolysis, a chemist decomposes 56 g of water
into its gaseous elements. How many grams of oxygen gas should she get
(theoretical yield)?
Bal. Equation:
Before
Change
__________________
After
2. Recall that liquid sodium reacts with chlorine gas to produce sodium chloride. You
want to produce 591 g of sodium chloride. How many grams of chlorine are needed?
Bal. Equation:
Before
Change
__________________
After
Modeling Chemistry
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U8 ws 2 v2.0
3. You eat 0.780 moles of glucose (70 M&Ms). Digestion of glucose, C6H12O6, is a
combustion reaction. How many grams of oxygen will you have to breathe in to
burn the glucose? How many grams of water vapor will your body use to digest this
tasty treat?
Bal. Equation:
Before
Change
__________________
After
4. Determine the moles of oxygen needed to combine with the 185.0 grams of
propane(C3H8) burned to heat the water for your morning shower.
5. Suppose 4.61 g of zinc was allowed to react with hydrochloric acid to produce zinc
chloride and hydrogen gas. How many grams of zinc chloride should you get?
Suppose that you actually recovered 8.56 g of zinc chloride. What is your percent
yield? Make your own BCA chart!
Modeling Chemistry
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U8 ws 2 v2.0
6. Determine the mass of carbon dioxide that should be produced in the reaction
between 27.5 g of ethane (C2H6) and excess oxygen. What is the % yield if 61.34 g
of carbon dioxide is actually recovered? Make your own BCA chart!
7. Determine the mass of water vapor you would expect to form (and the percent yield)
in the reaction between 15.8 g of ammonia (NH3) and excess oxygen to produce
water and nitrogen monoxide. The mass of water actually formed is 21.8 g.
8. The synthesis reaction between excess potassium and oxygen gas is 68.8 % efficient.
If you want to actually produce 17.36 grams of product by this reaction, how many
grams of potassium would need to react with the excess oxygen? You know what to
make!
Modeling Chemistry
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U8 ws 2 v2.0