Question

1) 1C 3 H 8 + 5O 2 à 3CO 2 + 4H 2 O
a. How many moles of carbon dioxide gas is produced when 10.0 moles of propane, (C 3 H 8 ), is
burned in oxygen?

b. How many moles of oxygen gas are needed to produce 20 moles of water?

2) 2SO 2 + 1O 2 + 2H 2 O à 2H 2 SO 4

a. If 12.5 mols of SO 2 react, how many moles of H 2 SO 4 will be produced?

b. If 20 moles of H 2 O are used, how many moles of oxygen would be used?

3) 2Al + 6HCl à 2AlCl 3 + 3H 2
a. If 18 moles of HCl are used, how many moles of AlCl 3 were produced?

b. How many moles of Al were used, If 11.5 moles of hydrogen is produced?

Answer 1

1) C3H8 + 5 O2 → 3 CO2 + 4 H2O
a. 10.0 mol C3H8 × (3 mol CO2 / 1 mol C3H8) = 30.0 mol CO2

b. Want 20 mol H2O. O2 required = 20 mol H2O × (5 mol O2 / 4 mol H2O) = 25 mol O2

2) 2 SO2 + 1 O2 + 2 H2O → 2 H2SO4
a. 12.5 mol SO2 × (2 mol H2SO4 / 2 mol SO2) = 12.5 mol H2SO4

b. 20 mol H2O × (1 mol O2 / 2 mol H2O) = 10 mol O2

3) 2 Al + 6 HCl → 2 AlCl3 + 3 H2
a. 18 mol HCl × (2 mol AlCl3 / 6 mol HCl) = 6 mol AlCl3

b. 11.5 mol H2 × (2 mol Al / 3 mol H2) = 7.67 mol Al (≈7.7 mol to three sig figs)