Chemistry: Stoichiometry Practice

Instructions:

• Balance the equation if it is not already balanced.

• Show your work using dimensional analysis (stoichiometry bridges).

• Use the periodic table for molar masses.

• Round your final answers to two decimal places.

1. Given the balanced equation: N2 + 3H2 -> 2NH3

How many moles of ammonia (NH3) are produced when 0.60 moles of nitrogen (N2) react completely?

2. Given the balanced equation: 2KClO3 -> 2KCl + 3O2

How many moles of oxygen gas (O2) are produced from the decomposition of 5.00 moles of potassium chlorate (KClO3)?

3. Given the balanced equation: Zn + 2HCl -> ZnCl2 + H2

How many grams of hydrogen gas (H2) are produced when 2.50 moles of zinc (Zn) react with excess hydrochloric acid?

4. Given the balanced equation: 2H2 + O2 -> 2H2O

How many grams of water (H2O) are produced if 4.00 moles of oxygen (O2) are consumed?

5. Given the balanced equation: CH4 + 2O2 -> CO2 + 2H2O

How many moles of carbon dioxide (CO2) are formed from the combustion of 32.00 grams of methane (CH4)?

6. Given the balanced equation: Mg + 2HCl -> MgCl2 + H2

How many moles of magnesium chloride (MgCl2) are produced if you start with 48.62 grams of magnesium (Mg)?

7. Given the balanced equation: C3H8 + 5O2 -> 3CO2 + 4H2O

How many grams of carbon dioxide (CO2) are produced when 22.05 grams of propane (C3H8) are burned?

8. Given the balanced equation: 4Fe + 3O2 -> 2Fe2O3

How many grams of iron (III) oxide (Fe2O3) can be made from 100.0 grams of iron (Fe)?

9. Reaction: Sodium metal reacts with chlorine gas to produce sodium chloride.

Equation: 2Na + Cl2 -> 2NaCl

Calculate the grams of sodium chloride (NaCl) produced if 5.00 grams of chlorine gas (Cl2) are reacted.

10. Reaction: Aluminum reacts with oxygen to form aluminum oxide.

Equation: 4Al + 3O2 -> 2Al2O3

If you have 54.00 grams of aluminum (Al), how many grams of aluminum oxide (Al2O3) will be produced?

Answer Key

1) 1.20 mol NH3

(0.60 mol N2 x 2 mol NH3 / 1 mol N2)

2) 7.50 mol O2

(5.00 mol KClO3 x 3 mol O2 / 2 mol KClO3)

3) 5.04 g H2

(2.50 mol Zn x 1 mol H2 / 1 mol Zn x 2.02 g H2/mol)

4) 144.16 g H2O

(4.00 mol O2 x 2 mol H2O / 1 mol O2 x 18.02 g H2O/mol)

5) 2.00 mol CO2

(32.00 g CH4 / 16.04 g/mol x 1 mol CO2 / 1 mol CH4)

6) 2.00 mol MgCl2

(48.62 g Mg / 24.31 g/mol x 1 mol MgCl2 / 1 mol Mg)

7) 66.02 g CO2

(22.05 g C3H8 / 44.10 g/mol x 3 mol CO2 / 1 mol C3H8 x 44.01 g CO2/mol)

8) 142.97 g Fe2O3

(100.0 g Fe / 55.85 g/mol x 2 mol Fe2O3 / 4 mol Fe x 159.69 g Fe2O3/mol)

9) 8.24 g NaCl

(5.00 g Cl2 / 70.90 g/mol x 2 mol NaCl / 1 mol Cl2 x 58.44 g NaCl/mol)

10) 101.96 g Al2O3

(54.00 g Al / 26.98 g/mol x 2 mol Al2O3 / 4 mol Al x 101.96 g Al2O3/mol)