12.3 Stoichiometry , Limiting Reagent p.1,2 only
Name:
Date:
POINTS: 2 point; equation balanced and calculation shown with all units. 1 point: correct
answer. 1 point correct unit
1. Tin(II) fluoride is added to some dental products to prevent cavities. What mass of Tin(II)
fluoride can be made from 55.0 g of HF if there is more than enough tin? Ref. holt p. 351
_____Sn + _____ HF
_____SnF2 + _____ H2
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2. In space shuttles, the CO2 that the crew exhales is removed from the air by a reaction with
canisters of lithium hydroxide, LiOH. On average, each astronaut exhales about 20.0 mol of CO2
daily. How many grams of water will be produced from 20.0 mol of CO2 if an excess of LiOH is
present? Ref. holt p 355
______ CO2
+ _____Li OH
_____Li2CO3 + _____ H20
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3. What mass of water must react with an excess of oxygen to produce 15.0 g
H2O2?
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______ H2O + _____O2
_______ H2O2
4. In an airbag, the chemical reaction below determines the amount of
Nitrogen gas (N2) that inflates the bag. Assume that 65.1 L of gas is needed
to inflate an air bag to the proper size. What mass of NaN3 must be
included to generate this volume of N2? Hint: calculate the number of
moles that 65.1 L of N2 gas contains at STP. Ref. Holt p 369
2 NaN3
2 Na + 3 N2
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5. Carbon monoxide can be combined with hydrogen to produce methanol,
CH3OH. Methanol is used as a clean burning fuel for some race cars. If you
had 152.5 g CO and 24.5 g H2, what mass of CH3OH could be produced?
What is the limiting reagent? Show your calculations. Ref. Holt p. 359
CO + 2 H2
CH3OH
6. In a reaction chamber, 3.0 mol of aluminum is mixed with 5.3 mol Cl2. The
reaction is described by this equation: Identify the limiting reagent for the
equation. Show your calculation for both reactants. ref. text p. 379 prob. 47.
2 Al + 3 Cl2
2 AlCl3
Stoichiometry and Percentage Yield:
7)
Balance this equation and state which of the six types of reaction is taking place: 5, 6, 7 guch
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____ Mg + ____ HNO3  ____ Mg(NO3)2 + ____ H2
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Type of reaction: __________________________/1
8)
If I start this reaction with 40 grams of magnesium and an excess of nitric acid, how many grams
of hydrogen gas will I produce?
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9)
If 1.7 grams of hydrogen is actually produced, what was my percent yield of hydrogen? See p
372
Percent Yield Calculation Answers
1)
Balance this equation and state which of the six types of reaction is taking place:
1 Mg + 2 HNO3  1 Mg(NO3)2 + 1 H2
Type of reaction: single displacement
2)
If I start this reaction with 40 grams of magnesium and an excess of nitric acid, how many grams
of hydrogen gas will I produce?

3)
3.3 grams (when Mg atomic mass = 24.3 grams)
If 1.7 grams of hydrogen is actually produced, what was my percent yield of hydrogen?

52%