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(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 8 g of Al? Assume the other reactants are in excess.

M(Al) = 26.98 g/molM(AlCl3) = 133.33 g/mol
m = g
2.Easy
m(H2​)n(H2​)n(H2​O)m(H2​O)÷ M(H2​)× 2/2× M(H2​O)

For the reaction 2H2 + O2 → 2H2O, what mass m of H2O forms from 5 g of H2? Assume the other reactants are in excess.

M(H2) = 2.016 g/molM(H2O) = 18.02 g/mol
m = g
3.Medium
m(X)n(X)n(MgO)m(MgO)÷ M(X)× 2/ν× M(MgO)

30 g of Mg and 10 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(NaCl)m(NaCl)÷ M(X)× 2/ν× M(NaCl)

16 g of Na and 16 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(Na)n(Na)n(NaCl)m(NaCl)÷ M(Na)× 2/2× M(NaCl)

In the reaction 2Na + Cl2 → 2NaCl, 30 g of Na reacts completely (the other reactants are in excess) and 41.94 g of NaCl is collected. Find the percent yield Y.

M(Na) = 22.99 g/molM(NaCl) = 58.44 g/molactual: 41.94 g
Y = %
6.Hard
m(C3​H8​)n(C3​H8​)n(CO2​)m(CO2​)÷ M(C3​H8​)× 3/1× M(CO2​)

In the reaction C3H8 + 5O2 → 3CO2 + 4H2O, 6 g of C3H8 reacts completely (the other reactants are in excess) and 13.47 g of CO2 is collected. Find the percent yield Y.

M(C3H8) = 44.1 g/molM(CO2) = 44.01 g/molactual: 13.47 g
Y = %

Answer key

  1. 1. m = 39.53 g
  2. 2. m = 44.69 g
  3. 3. m = 25.19 g
  4. 4. m = 26.38 g
  5. 5. Y = 55 %
  6. 6. Y = 74.99 %

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