Lesson 2.2 What Affects Solubility?

You know that sugar and salt dissolve easily in water. You also know that oil and water will not mix.

Read about solubility on page 46 in the textbook.

Question 1. Define solubility.

Question 2. Define soluble.

Question 3. Define insoluble.

 

Then, return here to continue this lesson.

 

The "Try This" activity on page 46 involves using a quarter of a glass of cooking oil. The oil is messy and must not be poured down the drain. Do not do this activity unless you have access to a disposal method for the oil.

Read the "Try This" activity on page 46. Then, watch the following demonstration of the activity and answer question 4.

Question 4. Complete the following sentences using these terms: soluble, insoluble, less dense, more dense, solution, solute, solvent.

  1. The oil stays on top of the water because it is --- than water.
  2. The oil and water are --- liquids.
  3. The drops of food colouring are --- than oil and --- than water.
  4. The drops of food colouring are --- in water and --- in oil.
  5. The final green coloured liquid is called a ---.
  6. The water in the green coloured liquid is called the --- .
  7. The food colouring is called the ---.

Then, return here to continue this lesson.

 

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Define solubility.

Solubility means how easily a solute dissolves in a solvent.

Question 2. Define soluble.

Soluble means that a solute dissolves in a solvent.

Question 3. Define insoluble.

Insoluble means that a solute does not dissolve in a solvent.

 

Click to return to where you left off in this lesson.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 4. Complete the following sentences using the terms: soluble, insoluble, less dense, more dense, solution, solute, solvent.

  1. The oil stays on top of the water because it is less dense than water.
  2. The oil and water are insoluble liquids.
  3. The drops of food colouring are soluble in water and insoluble in oil.
  4. The final green coloured water is called a solution.
  5. The water in the green coloured liquid is called the solvent.
  6. The food colouring is called the solute.

This is very interesting. Food colouring is insoluble in oil and is also more dense than oil. It sinks through the oil without dissolving until it hits the water on which the oil is floating. The glob of food colouring appears to be less dense than water and stays between the oil and water. When the surface tension was broken, the glob of food colouring sinks in the water and immediately begins dissolving because it is soluble in water. The resulting mixture is a green-coloured solution.


Click on the page forward to continue Lesson 2.