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

For the reaction 2Al + 3Cl₂ → 2AlCl₃, what mass m of AlCl₃ forms from 32 g of Al? Assume the other reactants are in excess.

M(Al) = 26.98 g/molM(AlCl₃) = 133.33 g/mol

m = g

2.Easy

For the reaction 2Na + Cl₂ → 2NaCl, what mass m of NaCl forms from 100 g of Na? Assume the other reactants are in excess.

M(Na) = 22.99 g/molM(NaCl) = 58.44 g/mol

m = g

3.Medium

24 g of Al and 32 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

4.Medium

12 g of Al and 20 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

In the reaction 2Mg + O₂ → 2MgO, 30 g of Mg reacts completely (the other reactants are in excess) and 38.79 g of MgO is collected. Find the percent yield Y.

M(Mg) = 24.31 g/molM(MgO) = 40.3 g/molactual: 38.79 g

Y = %

6.Hard

In the reaction 2Al + 3Cl₂ → 2AlCl₃, 10 g of Al reacts completely (the other reactants are in excess) and 43.49 g of AlCl₃ is collected. Find the percent yield Y.

M(Al) = 26.98 g/molM(AlCl₃) = 133.33 g/molactual: 43.49 g

Y = %

Answer key

1. m = 158.1 g
2. m = 254.2 g
3. m = 40.12 g
4. m = 25.07 g
5. Y = 78 %
6. Y = 88 %

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