Year 7 Science · Unit 2 · Lesson 18

Factors Affecting Solubility

Foundation Worksheet

Name

Date

Class

Learning Goals

Name the three factors that affect the rate of dissolving: temperature, stirring, and particle size.
Explain using particle ideas why each factor speeds up dissolving.
Distinguish between factors that change the rate and factors that change the maximum amount dissolved.

Warm Up

Odd one out

Circle the item that does not belong in each group. Then explain why it doesn't fit.

#	Group	Your answer (odd one + reason)
1	Stir faster Heat up Crush smaller Add more solute
2	Temperature Stirring Surface area Colour of cup
3	Powdered sugar Crushed tablet Fine salt Large sugar cube

Your Turn

Sort it!

Write each experimental change into the correct category box below.

Use hot water instead of cold Use cold water instead of hot Stir the solution continuously Crush the tablet into powder Use a whole sugar cube instead of powder Add the solute to still water Cool the water to 4°C Grind the salt to a finer grain Use the same temperature water Stir gently instead of fast

Increases rate of dissolving

Decreases rate of dissolving

No effect on rate

Show What You Know

1. A student crushes a sugar cube into fine powder and stirs it into water. Name TWO factors that are now helping the sugar dissolve faster. For each, explain why it increases the rate.

Recall 2 marks

2. Of the three factors (temperature, stirring, particle size), which is the ONLY one that changes the maximum amount of solute that can dissolve? Explain why.

Recall 2 marks

Wrap Up

In one sentence, what was the main idea of this lesson?