2.3: Reversible Changes

What is an example of a physical change?

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The rate of something tells us __________.

• how fast or slow something is happening or changing
• how far something is
• how big or small something is
• how much something costs

________ is when a solid is mixed into a liquid resulting in a solution.

• Evaporating

• Boiling

• Dissolving

• Melting

Label the picture.

a

b

c

solute

solvent

solution

What is an example of a SOLUBLE substance?

• sand

• sugar

• rice

• oil

Organise these options into the right categories

Groups:

(a) Reversible Changes

,

(b) Irreversible Changes

• boiling milk

• rusting of metal

• baking a cake

• mixing salt and water

• freezing bread

• melting ice cream

• burning a candle

• growing a plant

Why is mixing salt and water a reversible reaction?

• The salt can be recovered by filtering the solution.
• Mixing salt and water is an irreversible reaction.
• The salt can be separated from the water by distillation.
• The salt can be recovered from the solution by evaporating the water.

What happens to solute particles when it goes into a solvent?

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This picture shows a test to find out about factors that affect dissolving.

What factor that affects dissolving is being tested?

• The temperature of the solvent are the different.

• The particles of the solute are different sizes.

• The solute was not stirred completely.

This picture shows a test to find out about factors that affect dissolving.

What factors are the SAME in both beakers?

• The amount of the solvent

• The amount of the solute

• The beaker size

• The type of solute used

• The stirring of the solute and the solvent