Equation Stoichiometry Problems 3
Limiting Reactant, Percent Yield and
Thermochemical Calculations
1. If exactly 7.50 g of propane gas, C3H8, reacts with 6.00 g of oxygen gas,
a) write the BME and include the energy term:
b) calculate the mass of water produced:
c) calculate the energy released in this reaction:
d) calculate the mass of excess reactant that remains:
2. In the Haber Process, nitrogen gas reacts with hydrogen gas to produce ammonia
gas. If 2.00 kilograms of nitrogen gas reacts with 1.50 kilograms of hydrogen gas
a) write the BME including the energy term:
b) determine the limiting reactant and mass of ammonia formed:
c) determine the mass of excess reactant remaining after the reaction stops:
d) if 994 g of ammonia is actually collected, calculate the percent yield:
e) calculate the energy involved in this reaction and indicate whether the
energy was absorbed or released:
3. When carbon reacts with hydrogen gas, ethane gas is produced, having the
chemical formula C2H6.
a) write a BME and include the energy term:
if 540.0 g of carbon reacts with 125.0 g of hydrogen gas,
b) determine the limiting reactant and calculate the mass of ethane gas
produced:
c) calculate the mass of excess reactant leftover:
d) if 595.0 g of ethane gas is collected, calculate the percent yield:
e) calculate the energy involved in this reaction and indicate whether the
energy was absorbed or released:
4.
An aqueous solution containing 4.50 g of lead(II)chloride is mixed with an
aqueous solution containing 3.15 g of potassium sulfate.
a) write a BME:
b) calculate the mass of precipitate formed:
c) calculate the mass of excess reactant that remains:
5. A reaction between aqueous solutions of calcium nitrate and lithium sulfide
resulted in the production of 12.80 g of calcium sulfide. If this mass represented a
75.0% yield, calculate the mass of calcium nitrate that was required to produce
100% yield. Assume the lithium sulfide was in excess.