Bonding & Structure (1)

Question 1

Why did the balance reading decrease during the reaction?

Answer 1

Box 3 ( a gas was lost from the flask)

Question 2

Describe a safe method for making pure crystals of copper sulfate from copper carbonate and dilute sulfuric acid

Answer 2

• sulfuric acid in a beaker
• add copper carbonate one spatula at a time until it is in excess
• filter using filter paper and funnel
• filter excess copper carbonate
• pour solution into evaporating dish
• heat using Bunsen burner until solution is crystallised
• pat dry using filter paper
• wear safety goggles

Question 3

Give one reason why it is important for the percentage atom economy of a reaction to be as high as possible

Answer 3

Important for sustainable development

Question 4

Give the percentage of silver in 18 carat gold

Answer 4

5%

Question 5

Suggest two reasons why 9 carat gold is often used instead of pure gold to make jewellery

Answer 5

• 9 carat gold is cheaper than pure gold
• Pure gold is soft