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(N2​)n(N2​)n(NH3​)m(NH3​)÷ M(N2​)× 2/1× M(NH3​)

For the reaction N2 + 3H2 → 2NH3, what mass m of NH3 forms from 16 g of N2? Assume the other reactants are in excess.

M(N2) = 28.02 g/molM(NH3) = 17.03 g/mol
m = g
2.Easy
m(CaCO3​)n(CaCO3​)n(CaO)m(CaO)÷ M(CaCO3​)× 1/1× M(CaO)

For the reaction CaCO3 → CaO + CO2, what mass m of CaO forms from 12 g of CaCO3? Assume the other reactants are in excess.

M(CaCO3) = 100.09 g/molM(CaO) = 56.08 g/mol
m = g
3.Medium
m(X)n(X)n(CO2​)m(CO2​)÷ M(X)× 1/ν× M(CO2​)

12 g of CH4 and 48 g of O2 react according to CH4 + 2O2 → CO2 + 2H2O. What mass m of CO2 can form?

M(CH4) = 16.04M(O2) = 32M(CO2) = 44.01 g/mol
m = g
4.Medium
m(X)n(X)n(MgO)m(MgO)÷ M(X)× 2/ν× M(MgO)

8 g of Mg and 20 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
5.Hard
m(Al)n(Al)n(AlCl3​)m(AlCl3​)÷ M(Al)× 2/2× M(AlCl3​)

In the reaction 2Al + 3Cl2 → 2AlCl3, 10 g of Al reacts completely (the other reactants are in excess) and 34.59 g of AlCl3 is collected. Find the percent yield Y.

M(Al) = 26.98 g/molM(AlCl3) = 133.33 g/molactual: 34.59 g
Y = %
6.Hard
m(H2​)n(H2​)n(H2​O)m(H2​O)÷ M(H2​)× 2/2× M(H2​O)

In the reaction 2H2 + O2 → 2H2O, 16 g of H2 reacts completely (the other reactants are in excess) and 88.67 g of H2O is collected. Find the percent yield Y.

M(H2) = 2.016 g/molM(H2O) = 18.02 g/molactual: 88.67 g
Y = %

Answer key

  1. 1. m = 19.45 g
  2. 2. m = 6.724 g
  3. 3. m = 32.93 g
  4. 4. m = 13.26 g
  5. 5. Y = 69.99 %
  6. 6. Y = 62 %

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