Unit 1: Chemcial Reactions - Characteristics

Question 1

What are the characteristics to describe a Physical Change?

Answer 1

1. No new substance forms
2. Changes are reversible or temporary
3. There is no change in mass (weight)
4. A small amount of heat / energy is required

Question 2

What are the characteristics to describe a Chemical Change?

Answer 2

1. A new substance is formed
2. Changes are irreversible or permanent
3. There is a change in mass (weight)
4. Energy / heat is taken in or given out

Question 3

What happens to Iodine when heated?

Answer 3

Iodine, when heated, changes to a purple vapour, however changes back, when cooled, to shiny black crystals (Physical change)

Question 4

What happens to Zinc Oxide when heated?

Answer 4

Zinc Oxide, when heated, changes from a white solid to a yellow solid, but changes back to a white solid when cooled (Physical change)

Question 5

Describe the colour changes when Copper Sulfate is heated

Answer 5

When blue Copper Sulfate is heated, a new white substance is produced and steam is given off (Chemical change)

Question 6

Describe the colour changes when Copper Carbonate is heated

Answer 6

When green Copper Carbonate is heated, a new black solid is produced (Chemical change)

Question 7

What happens when Magnesium is heated?

Answer 7

When grey Magnesium is heated, a new white solid (ash) is formed (Chemical change)