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 40 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(C3​H8​)n(C3​H8​)n(CO2​)m(CO2​)÷ M(C3​H8​)× 3/1× M(CO2​)

For the reaction C3H8 + 5O2 → 3CO2 + 4H2O, what mass m of CO2 forms from 32 g of C3H8? Assume the other reactants are in excess.

M(C3H8) = 44.1 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)

30 g of Mg and 16 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(AlCl3​)m(AlCl3​)÷ M(X)× 2/ν× M(AlCl3​)

24 g of Al and 48 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
5.Hard
m(N2​)n(N2​)n(NH3​)m(NH3​)÷ M(N2​)× 2/1× M(NH3​)

In the reaction N2 + 3H2 → 2NH3, 24 g of N2 reacts completely (the other reactants are in excess) and 26.55 g of NH3 is collected. Find the percent yield Y.

M(N2) = 28.02 g/molM(NH3) = 17.03 g/molactual: 26.55 g
Y = %
6.Hard
m(N2​)n(N2​)n(NH3​)m(NH3​)÷ M(N2​)× 2/1× M(NH3​)

In the reaction N2 + 3H2 → 2NH3, 6 g of N2 reacts completely (the other reactants are in excess) and 6.64 g of NH3 is collected. Find the percent yield Y.

M(N2) = 28.02 g/molM(NH3) = 17.03 g/molactual: 6.64 g
Y = %

Answer key

  1. 1. m = 48.62 g
  2. 2. m = 95.8 g
  3. 3. m = 40.3 g
  4. 4. m = 60.18 g
  5. 5. Y = 91.01 %
  6. 6. Y = 91.04 %

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