WA3 Revision 2 G3

What indicates a chemical change has occurred?

• Formation of new substance
• Change in shape
• Change in size
• Change in position

Answer explanation

Chemical changes create new substances

Write the word equation for rusting:

• Iron + Oxygen → Iron Oxide
• Iron → Rust
• Iron + Water → Rust
• Iron → Iron Oxide

Answer explanation

Rusting requires both iron and oxygen

What happens to atoms in chemical reactions?

• Rearrange but don't disappear
• Get destroyed
• Are created
• Disappear

Answer explanation

Law of Conservation of Matter

During a chemical reaction, mass is:

• Conserved
• Lost
• Gained
• Doubled

Answer explanation

Mass cannot be created or destroyed

Which is NOT a type of chemical change?

• Melting ice
• Rusting
• Burning
• Photosynthesis

Answer explanation

Melting is a physical change

What happens when acid reacts with an alkali?

• Neutralization
• Explosion
• Formation of hydrogen
• Evaporation

Answer explanation

Acids and alkalis form salt and water

How does Universal Indicator show pH?

• Different colors for different pH
• Same color always
• No color change
• Only two colors

Answer explanation

Universal Indicator shows pH range

What does photosynthesis need?

• Light, CO2, water
• Only water
• Only light
• Only CO2

Answer explanation

Plants need multiple ingredients

Which shows cellular respiration?

• Glucose + Oxygen → CO2 + Water + Energy
• Glucose → Energy
• Oxygen → CO2
• Food → Energy

Answer explanation

Cellular respiration breaks down glucose

Which indicator does not turn red in acid?

• Litmus paper
• Universal Indicator
• pH meter
• All of these

Answer explanation

pH meters have do not display a colour, only a number