1. Temperature & Solubility
D. Crowley, 2007

2. Temperature & Solubility
Sunday, December 02, 2018
Temperature & Solubility
To know how temperature affects solubility

3. Word-search Have a go at the particle word-search
See how many words you can find in the next five minutes…

4. Particles Word-search

5. Solubility Are insoluble substance always insoluble?!
Some substances which are insoluble in one solvent, may be soluble in a different solvent
E.g. salt does not dissolve in petrol, but in water it will!

6. Solubility Some substances are more soluble than others
Very soluble substances have a high solubility
Why is it a good idea to wash dishes in hot, rather than cold water (think about temperature and solubility)
The solubility of most substances increases as the temperature does
This means most substances become more soluble in hot water, rather than cold water, meaning it becomes easier to wash our dishes!

7. Experiment
You are going to investigate how heat affects the solubility of salt in water
What would be a good way to investigate this?
What will be your independent variable (one changed)?
What will be your dependent variable (one changed by exp.)?
What will you need to control?
What equipment will you need?
What do you predict?

8. Experiment
We could add a known amount of salt to a beaker of water, and record how long it took to dissolve
We could then repeat this, to different beakers of water, at different temperatures
This would show us how temperature affects solubility
Independent variable: temperature
Dependent variable: time taken for salt to dissolve
Control: water type; amount of salt; time of experiment etc…

9. Results Design a results table…
These are usually the things you have measured
This is usually the thing you change
Use a pencil
and ruler
Always include your units (e.g. cm, sec, N etc…)

10. Mass of salt which dissolved (grams)
Results
Temperature of water
(C)
Mass of salt which dissolved (grams) 1 2 3
Average
20C
30C
60C
Remember: everything else except the temperature of water is kept constant

11. Graph You now need to graph the class results on the board
Remember, the variable you changed goes on the bottom (temperature) and the variable which was changed by the experiment goes up the side (mass of salt added)
You will need to draw a line graph
You will need a title, labels, line of best fit and explanation as to what your results show

12. Graph

13. We could predict that 7.5g of salt would dissolve in water at 100°C
Graph Data
How could you use the graph below to predict how much salt would dissolve at 100oC?
We could predict that 7.5g of salt would dissolve in water at 100°C