Stoichiometry worksheet with answers

Free printable Stoichiometry worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
m(CaCO3​)n(CaCO3​)n(CO2​)m(CO2​)÷ M(CaCO3​)× 1/1× M(CO2​)

For the reaction CaCO3 → CaO + CO2, what mass m of CO2 forms from 25 g of CaCO3? Assume the other reactants are in excess.

M(CaCO3) = 100.09 g/molM(CO2) = 44.01 g/mol
m = g
2.Easy
m(CH4​)n(CH4​)n(CO2​)m(CO2​)÷ M(CH4​)× 1/1× M(CO2​)

For the reaction CH4 + 2O2 → CO2 + 2H2O, what mass m of CO2 forms from 50 g of CH4? Assume the other reactants are in excess.

M(CH4) = 16.04 g/molM(CO2) = 44.01 g/mol
m = g
3.Medium
m(X)n(X)n(MgO)m(MgO)÷ M(X)× 2/ν× M(MgO)

24 g of Mg and 24 g of O2 react according to 2Mg + O2 → 2MgO. What mass m of MgO can form?

M(Mg) = 24.31M(O2) = 32M(MgO) = 40.3 g/mol
m = g
4.Medium
m(X)n(X)n(CO2​)m(CO2​)÷ M(X)× 3/ν× M(CO2​)

12 g of C3H8 and 10 g of O2 react according to C3H8 + 5O2 → 3CO2 + 4H2O. What mass m of CO2 can form?

M(C3H8) = 44.1M(O2) = 32M(CO2) = 44.01 g/mol
m = g
5.Hard
m(CH4​)n(CH4​)n(H2​O)m(H2​O)÷ M(CH4​)× 2/1× M(H2​O)

In the reaction CH4 + 2O2 → CO2 + 2H2O, 24 g of CH4 reacts completely (the other reactants are in excess) and 33.43 g of H2O is collected. Find the percent yield Y.

M(CH4) = 16.04 g/molM(H2O) = 18.02 g/molactual: 33.43 g
Y = %
6.Hard
m(C6​H12​O6​)n(C6​H12​O6​)n(C2​H5​OH)m(C2​H5​OH)÷ M(C6​H12​O6​)× 2/1× M(C2​H5​OH)

In the reaction C6H12O6 → 2C2H5OH + 2CO2, 30 g of C6H12O6 reacts completely (the other reactants are in excess) and 11.97 g of C2H5OH is collected. Find the percent yield Y.

M(C6H12O6) = 180.16 g/molM(C2H5OH) = 46.07 g/molactual: 11.97 g
Y = %

Answer key

  1. 1. m = 10.99 g
  2. 2. m = 137.2 g
  3. 3. m = 39.79 g
  4. 4. m = 8.252 g
  5. 5. Y = 61.99 %
  6. 6. Y = 78.02 %

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