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 10 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(Mg)n(Mg)n(MgO)m(MgO)÷ M(Mg)× 2/2× M(MgO)

For the reaction 2Mg + O2 → 2MgO, what mass m of MgO forms from 20 g of Mg? Assume the other reactants are in excess.

M(Mg) = 24.31 g/molM(MgO) = 40.3 g/mol
m = g
3.Medium
m(X)n(X)n(NH3​)m(NH3​)÷ M(X)× 2/ν× M(NH3​)

8 g of N2 and 40 g of H2 react according to N2 + 3H2 → 2NH3. What mass m of NH3 can form?

M(N2) = 28.02M(H2) = 2.016M(NH3) = 17.03 g/mol
m = g
4.Medium
m(X)n(X)n(MgO)m(MgO)÷ M(X)× 2/ν× M(MgO)

12 g of Mg and 64 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(C3​H8​)n(C3​H8​)n(CO2​)m(CO2​)÷ M(C3​H8​)× 3/1× M(CO2​)

In the reaction C3H8 + 5O2 → 3CO2 + 4H2O, 10 g of C3H8 reacts completely (the other reactants are in excess) and 28.14 g of CO2 is collected. Find the percent yield Y.

M(C3H8) = 44.1 g/molM(CO2) = 44.01 g/molactual: 28.14 g
Y = %
6.Hard
m(CaCO3​)n(CaCO3​)n(CaO)m(CaO)÷ M(CaCO3​)× 1/1× M(CaO)

In the reaction CaCO3 → CaO + CO2, 8 g of CaCO3 reacts completely (the other reactants are in excess) and 2.47 g of CaO is collected. Find the percent yield Y.

M(CaCO3) = 100.09 g/molM(CaO) = 56.08 g/molactual: 2.47 g
Y = %

Answer key

  1. 1. m = 12.16 g
  2. 2. m = 33.16 g
  3. 3. m = 9.724 g
  4. 4. m = 19.89 g
  5. 5. Y = 93.99 %
  6. 6. Y = 55.1 %

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