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(CaCO3​)n(CaCO3​)n(CO2​)m(CO2​)÷ M(CaCO3​)× 1/1× M(CO2​)

For the reaction CaCO3 → CaO + CO2, what mass m of CO2 forms from 40 g of CaCO3? Assume the other reactants are in excess.

M(CaCO3) = 100.09 g/molM(CO2) = 44.01 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 25 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(NaCl)m(NaCl)÷ M(X)× 2/ν× M(NaCl)

16 g of Na and 64 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
4.Medium
m(X)n(X)n(H2​O)m(H2​O)÷ M(X)× 2/ν× M(H2​O)

24 g of H2 and 10 g of O2 react according to 2H2 + O2 → 2H2O. What mass m of H2O can form?

M(H2) = 2.016M(O2) = 32M(H2O) = 18.02 g/mol
m = g
5.Hard
m(C6​H12​O6​)n(C6​H12​O6​)n(CO2​)m(CO2​)÷ M(C6​H12​O6​)× 2/1× M(CO2​)

In the reaction C6H12O6 → 2C2H5OH + 2CO2, 8 g of C6H12O6 reacts completely (the other reactants are in excess) and 3.67 g of CO2 is collected. Find the percent yield Y.

M(C6H12O6) = 180.16 g/molM(CO2) = 44.01 g/molactual: 3.67 g
Y = %
6.Hard
m(N2​)n(N2​)n(NH3​)m(NH3​)÷ M(N2​)× 2/1× M(NH3​)

In the reaction N2 + 3H2 → 2NH3, 4 g of N2 reacts completely (the other reactants are in excess) and 3.99 g of NH3 is collected. Find the percent yield Y.

M(N2) = 28.02 g/molM(NH3) = 17.03 g/molactual: 3.99 g
Y = %

Answer key

  1. 1. m = 17.59 g
  2. 2. m = 41.44 g
  3. 3. m = 40.67 g
  4. 4. m = 11.26 g
  5. 5. Y = 93.9 %
  6. 6. Y = 82.06 %

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