Section 1- Particles and Mixtures P2

Question 1

Define solubility:

Answer 1

Solubility is a measure of how much solute will dissolve in a solvent
-the ability of a substance to dissolve in a solvent is known as its solubility

Question 2

What is solubility often measured in?

Answer 2

grams of solute per 100 grams of solvent

Question 3

What is the effect of temperature on solubility?

Answer 3

as the temperature increases the solubility of most solid substances increases

Question 4

What is a graph of solubility against temperature known as?

Answer 4

a solubility curve

Question 5

What can you use solubility curves for?

Answer 5

to see the solubility of a substance at a specific temperature

Question 6

Describe a practical for how you can investigate how temperature affects solubility:

Answer 6

(using ammonium chloride)

• make a saturated solution of ammonium chloride and 10cm³ of water in a boiling tube
• stir the solution and place it in a 25°C water bath
• after 5 mins, check all excess solid has fallen to the bottom, and check the temperature to be 25°C
• weigh an empty evaporating basin, pour the solution in without the undissolved solid
• re-weigh the basin and its contents, then gently heat with a Bunsen burner to remove the water
• re-weigh the basin
• repeat the experiment at different temperatures
• you can use your results to plot a solubility curve

Question 7

When using evaporation to try and separate out a solid from its solution why do you heat it gently?

Answer 7

To make sure you don’t also turn the solid into a gas and then loose both your liquid and solid

Question 8

How do you calculate solubility from masses of a solid and water?

Answer 8

solubility (g per 100g of solvent) =
{mass of solid(g)÷mass of water removed(g)} x 100

-in this case the solvent is water