STOICHIOMETRY PRACTICE

• 1. When solid aluminum chloride is heated at high temperatures, solid aluminum and chlorine gas are produced.

• a. Write and balance the reaction that occurs.on the top of your white board.

• 1. When solid aluminum chloride is heated at high temperatures, solid aluminum and chlorine gas are produced.

• a. Write and balance the reaction that occurs. 2 AlCl3 → 2Al + 3Cl2

c. What mass of aluminum chloride must decompose in order to form 10.25g of aluminum?

• c. What mass of aluminum chloride must decompose in order to form 10.25g of aluminum?

10.25g Al 1 mole Al 2 moles AlCl3 133.33g AlCl3 =

26.98 g Al 2 mole Al 1 mole AlCl3

50.65g AlCl3

• d. What mass of aluminum will be produced if 13.5g of chlorine are produced?

• d. What mass of aluminum will be produced if 13.5g of chlorine are produced?

13.5 g Cl2 1mole Cl2 2moles Al 26.98g Al = 3.42 g Al 70.90 g Cl2 3 moles Cl2 1mole

• e. What mass of aluminum will be produced if 20.5g of chlorine are produced?

• e. What mass of aluminum will be produced if 20.5g of chlorine are produced?

20.5g Cl2 1 mole Cl2 2moles Al 26.98g Al = 5.20 g Al 70.90 g Cl2 3moles Cl2 1mole Al

• f. How many atoms of aluminum will be produced if 20.5g of chlorine are produced?

• f. How many atoms of aluminum will be produced if 20.5g of chlorine are produced?

20.5g Cl2 1 mole Cl2 2moles Al 6.02 x 1023

70.90 g Cl2 3moles Cl2 1mole Al

=1.16 x 1023 atoms Al

• g. What mass of chlorine will be produced if 5.00g of aluminum chloride decompose?

• g. What mass of chlorine will be produced if 5.00g of aluminum chloride decompose?

• 5.00g AlCl3 1mole AlCl3 3moles Cl2 70.90g Cl2 = 133.33g AlCl3 2 moles AlCl3 1mole Cl2

3.99 g Cl2

• 2. When flourine is bubbled through a hydrobromic acid solution, bromine and hydrofluoric acid are formed.

• a. Write the balanced equation for the reaction.

• b. What type of reaction is this?

• 2. When flourine is bubbled through a hydrobromic acid solution, bromine and hydrofluoric acid are formed.

• a. Write the balanced equation for the reaction.

• F2 + 2HBr → Br2 + 2HF

• b. What type of reaction is this?• Single replacement

• b. What mass of bromine will be formed if 25.0g of fluorine react with excess hydrofluoric acid, and the reaction has an 83.4% yield?

• b. What mass of bromine will be formed if 25.0g of fluorine react with excess hydrofluoric acid and the reaction has an 83.4% yield?

25.0 g F2 1mole F2 1mole Br2 159.80g Br2 expected 83.4g Br2

38.0 g F2 1mole F2 1mole Br2 100g expected

• = 87.7g Br2

20.0g of fluorine gas react with excess hydrobromic acid. Determine the mass of hydrofluoric acid formed if the reaction has a 92.7% yield.

c. 20.0g of fluorine gas react with excess hydrobromic acid. Determine the mass of hydrofluoric acid formed if the reaction has a 92.7% yield. 20.0g F2 1 mol F2 2 mol HF 20.01g HF expected 92.7g HF formed

38.00g F2 1 mol F2 1 mol HF 100g expected

= 19.5g HF

• d. What mass of hydrobromic acid must react with excess fluorine in order to form 16.0g of bromine, assuming the reaction has an 85.0% yield?

• d. What mass of hydrobromic acid must react with excess fluorine in order to form 16.0g of bromine, assuming the reaction has an 85.0% yield?

16.0g Br2 formed 100g Br2 expected 1molBr2 2mol HBr 80.91g HBr

85.0g Br2 formed 159.8g Br2 1 mole Br2 1 mole HBr

= 13.8g HBr

• e. A student reacts 725mL of fluorine gas with excess hydrobromic acid at STP. The reaction produces 1.10g of hydrofluoric acid. Determine the % yield.

• e. A student reacts 725mL of fluorine gas with excess hydrobromic acid at STP. The reaction produces 1.10g of hydrofluoric acid. Determine the % yield.

0.725L F2 1molF2 2mol HF 20.01g HF = 1.30g HF expected

22.4L F2 1 mole F2 1 mole HF

% yield = 1.10g HF x 100 = 84.6% 1.30g HF

• 3. Iron reacts with sulfuric acid to form iron(III) sulfate and hydrogen gas.

• a. Write the balanced reaction below.

b. What type of reaction is this?

• 3. Iron reacts with sulfuric acid to form iron(III) sulfate and hydrogen gas.

• a. Write the balanced reaction below.

• 2Fe + 3H2SO4 → Fe2(SO4)3 + 3H2

• b. What type of reaction is this?• Single Replacement

• c. What mass of iron is needed to react with 10.5g of sulfuric acid?

• c. What mass of iron is needed to react with 10.5g of sulfuric acid?

10.5 g H2SO4 1 mol H2SO4 2 moles Fe 55.85 g Fe =

98.09 g 3 moles H2SO4 1 moles Fe

3.98g Fe

• d. What mass of iron(III) sulfate will be formed if 5.5g of iron react with excess sulfuric acid, and the reaction has a 94.0% yield?

• d. What mass of iron(III) sulfate will be formed if 5.5g of iron react with excess sulfuric acid, and the reaction has a 94.0% yield?

5.5g Fe 1mol Fe 1mol Fe2(SO4)3 399.91 g expected 94.0g formed 55.85 g 2mole Fe 1mol Fe2(SO4)3 100g expected

= 19g Fe2(SO4)3

• What mass of sulfuric acid is needed to form 18.0L of hydrogen gas, at STP, if the reaction has a 75.0% yield?

• What mass of sulfuric acid is needed to form 18.0L of hydrogen gas, at STP, if the reaction has a 75.0% yield?

• 18.0L H2 100 L H2 expected 1 mol H2SO4 3mol 98.09g

75.0L formed 22.4 L H2 1 mol H2 1 mol H2SO4

= 105g H2SO4

4. When solid calcium nitride is heated at high temperatures, solid calcium and nitrogen gas are produced.

• a. Write and balance the reaction that occurs.

• b. Identify the reaction type.

4. When solid calcium nitride is heated at high temperatures, solid calcium and nitrogen gas are produced.

• a. Write and balance the reaction that occurs. Ca3N2 → 3Ca + N2

• b. Identify the reaction type.• Decomposition

c. What mass of calcium nitride must decompose in order to form 10.25g of calcium?

c. What mass of calcium nitride must decompose in order to form 10.25g of calcium?

10.25g Ca 1mol Ca 1mol Ca3N2 148 g = 12.6 g Ca3N2

40g 3mol Ca 1mol Ca3N2

• d. What mass of calcium will be produced if 13.5g of nitrogen are produced?

• d. What mass of calcium will be produced if 13.5g of nitrogen are produced?

13.5g N2 1mol N2 3mols Ca 40g = 57.9 g Ca

28g 1mol N2 1mol Ca

• e. What volume of nitrogen, assuming the reaction is at STP, will be produced if 5.00g of calcium nitride decompose?

• e. What volume of nitrogen, assuming the reaction is at STP, will be produced if 5.00g of calcium nitride decompose?

5.00g Ca3N2 1mol Ca3N2 1mol N2 22.4L = .76 L N2

148 g 1mol Ca3N2 1mol N2