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(Fe2​O3​)n(Fe2​O3​)n(CO2​)m(CO2​)÷ M(Fe2​O3​)× 3/1× M(CO2​)

For the reaction Fe2O3 + 3CO → 2Fe + 3CO2, what mass m of CO2 forms from 12 g of Fe2O3? Assume the other reactants are in excess.

M(Fe2O3) = 159.69 g/molM(CO2) = 44.01 g/mol
m = g
2.Easy
m(C6​H12​O6​)n(C6​H12​O6​)n(CO2​)m(CO2​)÷ M(C6​H12​O6​)× 2/1× M(CO2​)

For the reaction C6H12O6 → 2C2H5OH + 2CO2, what mass m of CO2 forms from 32 g of C6H12O6? Assume the other reactants are in excess.

M(C6H12O6) = 180.16 g/molM(CO2) = 44.01 g/mol
m = g
3.Medium
m(X)n(X)n(Fe)m(Fe)÷ M(X)× 2/ν× M(Fe)

30 g of Fe2O3 and 20 g of CO react according to Fe2O3 + 3CO → 2Fe + 3CO2. What mass m of Fe can form?

M(Fe2O3) = 159.69M(CO) = 28.01M(Fe) = 55.85 g/mol
m = g
4.Medium
m(X)n(X)n(H2​O)m(H2​O)÷ M(X)× 2/ν× M(H2​O)

24 g of CH4 and 80 g of O2 react according to CH4 + 2O2 → CO2 + 2H2O. What mass m of H2O can form?

M(CH4) = 16.04M(O2) = 32M(H2O) = 18.02 g/mol
m = g
5.Hard
m(N2​)n(N2​)n(NH3​)m(NH3​)÷ M(N2​)× 2/1× M(NH3​)

In the reaction N2 + 3H2 → 2NH3, 20 g of N2 reacts completely (the other reactants are in excess) and 20.66 g of NH3 is collected. Find the percent yield Y.

M(N2) = 28.02 g/molM(NH3) = 17.03 g/molactual: 20.66 g
Y = %
6.Hard
m(Mg)n(Mg)n(MgO)m(MgO)÷ M(Mg)× 2/2× M(MgO)

In the reaction 2Mg + O2 → 2MgO, 4 g of Mg reacts completely (the other reactants are in excess) and 6.03 g of MgO is collected. Find the percent yield Y.

M(Mg) = 24.31 g/molM(MgO) = 40.3 g/molactual: 6.03 g
Y = %

Answer key

  1. 1. m = 9.921 g
  2. 2. m = 15.63 g
  3. 3. m = 20.98 g
  4. 4. m = 45.05 g
  5. 5. Y = 84.98 %
  6. 6. Y = 90.94 %

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