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(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 16 g of Mg? Assume the other reactants are in excess.

M(Mg) = 24.31 g/molM(MgO) = 40.3 g/mol
m = g
2.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
3.Medium
m(X)n(X)n(H2​O)m(H2​O)÷ M(X)× 4/ν× M(H2​O)

12 g of C3H8 and 40 g of O2 react according to C3H8 + 5O2 → 3CO2 + 4H2O. What mass m of H2O can form?

M(C3H8) = 44.1M(O2) = 32M(H2O) = 18.02 g/mol
m = g
4.Medium
m(X)n(X)n(NH3​)m(NH3​)÷ M(X)× 2/ν× M(NH3​)

24 g of N2 and 16 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
5.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 6.2 g of NH3 is collected. Find the percent yield Y.

M(N2) = 28.02 g/molM(NH3) = 17.03 g/molactual: 6.2 g
Y = %
6.Hard
m(Na)n(Na)n(NaCl)m(NaCl)÷ M(Na)× 2/2× M(NaCl)

In the reaction 2Na + Cl2 → 2NaCl, 4 g of Na reacts completely (the other reactants are in excess) and 8.64 g of NaCl is collected. Find the percent yield Y.

M(Na) = 22.99 g/molM(NaCl) = 58.44 g/molactual: 8.64 g
Y = %

Answer key

  1. 1. m = 26.52 g
  2. 2. m = 39.53 g
  3. 3. m = 18.02 g
  4. 4. m = 29.17 g
  5. 5. Y = 85.01 %
  6. 6. Y = 84.97 %

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