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(C3​H8​)n(C3​H8​)n(H2​O)m(H2​O)÷ M(C3​H8​)× 4/1× M(H2​O)

For the reaction C3H8 + 5O2 → 3CO2 + 4H2O, what mass m of H2O forms from 8 g of C3H8? Assume the other reactants are in excess.

M(C3H8) = 44.1 g/molM(H2O) = 18.02 g/mol
m = g
2.Easy
m(Al)n(Al)n(AlCl3​)m(AlCl3​)÷ M(Al)× 2/2× M(AlCl3​)

For the reaction 2Al + 3Cl2 → 2AlCl3, what mass m of AlCl3 forms from 5 g of Al? Assume the other reactants are in excess.

M(Al) = 26.98 g/molM(AlCl3) = 133.33 g/mol
m = g
3.Medium
m(X)n(X)n(AlCl3​)m(AlCl3​)÷ M(X)× 2/ν× M(AlCl3​)

10 g of Al and 40 g of Cl2 react according to 2Al + 3Cl2 → 2AlCl3. What mass m of AlCl3 can form?

M(Al) = 26.98M(Cl2) = 70.9M(AlCl3) = 133.33 g/mol
m = g
4.Medium
m(X)n(X)n(NaCl)m(NaCl)÷ M(X)× 2/ν× M(NaCl)

10 g of Na and 32 g of Cl2 react according to 2Na + Cl2 → 2NaCl. What mass m of NaCl can form?

M(Na) = 22.99M(Cl2) = 70.9M(NaCl) = 58.44 g/mol
m = g
5.Hard
m(C3​H8​)n(C3​H8​)n(H2​O)m(H2​O)÷ M(C3​H8​)× 4/1× M(H2​O)

In the reaction C3H8 + 5O2 → 3CO2 + 4H2O, 8 g of C3H8 reacts completely (the other reactants are in excess) and 12.29 g of H2O is collected. Find the percent yield Y.

M(C3H8) = 44.1 g/molM(H2O) = 18.02 g/molactual: 12.29 g
Y = %
6.Hard
m(Mg)n(Mg)n(MgO)m(MgO)÷ M(Mg)× 2/2× M(MgO)

In the reaction 2Mg + O2 → 2MgO, 8 g of Mg reacts completely (the other reactants are in excess) and 12.07 g of MgO is collected. Find the percent yield Y.

M(Mg) = 24.31 g/molM(MgO) = 40.3 g/molactual: 12.07 g
Y = %

Answer key

  1. 1. m = 13.08 g
  2. 2. m = 24.71 g
  3. 3. m = 49.42 g
  4. 4. m = 25.42 g
  5. 5. Y = 93.99 %
  6. 6. Y = 91.01 %

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