W2 May S4 Pure Chem Mid Year Revision 5 - Chemical Calculations

What is the relative formula mass of aluminium sulfate?

• 75

• 123

• 123 g

• 342

When 60 g of an unknown carbonate X was heated, 36 g of solid product was found at the end of the reaction. What is the mass of CO₂ produced?

• 12 g

• 24 g

• 36 g

• 60 g

Sodium bicarbonate, also known as baking soda, is an alkaline substance with a molecular formula of NaHCO₃. 

What mass of sodium bicarbonate is required to exactly neutralise 50 cm³ of 1.0 mol/dm³ hydrochloric acid? 

Note: Ar of H: 1,  Ar of C: 12,  Ar of O: 16,  Ar of H: 1

• 1.6 g

• 2.5 g

• 4.2 g

• 7.3 g

25 cm³ of 0.5 mol/dm³ sulfuric acid was added to 50 cm³ of 1.0 mol/dm³ aqueous ammonium hydroxide. What is the pH of the resulting solution?

• 1

• 4

• 7

• 9

1.6 g of zinc was added to 30 cm³ of 0.9 mol/dm³ sulfuric acid. It was observed that a colourless gas which causes a lighted splint to extinguish with a ‘pop’ sound was emitted. What is the total volume of gas collected? 

Note: The Ar of zinc is 65.

• 0.591 dm³

• 0.648 dm³

• 0.762 dm³

• 1.20 dm³