Topic 2: Mixtures

Question 1

What does mixture mean?

Answer 1

A mixture is when two or more different substances are added together.

Question 2

In some mixtures you can easily see the different substances. What are these mixtures called?

Answer 2

Heterogeneous mixtures

Question 3

In some mixtures, you can’t see the different substances that have been added because they dissolved into each other completely. What do you call these mixtures?

Answer 3

Homogeneous mixtures

Question 4

There is a bowl with rice and barley grains. Is this mixture a homogeneous or heterogeneous mixture?

Answer 4

heterogeneous mixture

Question 5

There is a cup of coffee.
Is this mixture a homogeneous or heterogeneous mixture?

Answer 5

homogeneous mixture

Question 6

Name different ways of separating mixtures.

Answer 6

Hand separation
Sieving
Filtering
Settling
Decanting

Question 7

If you have a mixture of rice and barley, how would you go about separating the mixture?

Answer 7

You can separate the mixture by hand by pouring it onto a table and picking the rice and barley out to separate them into two piles.

Question 8

You have a mixture of rice and sugar. What would the best way be to separate the mixture and why would this work?

Answer 8

The best way to separate rice and sugar would be to use a sieve.
The sugar grains are much smaller than the rice grains. The sugar grains will pass through the sieve while the rice grains stay behind, because they are too big to pass through the sieve.

Question 9

If you have a mixture of sand and water, would the best way to separate this mixture be “by hand”?
If you do not agree, give a reason for your answer and what would your solution be?

Answer 9

No, separation by hand is not the best way.
Separating sand from water by hand would take too long.
You can separate sand and water using a filtering process. You can use a paper towel or cloth to pour the mixture onto. The water will pass through while the sand stays behind.

Question 10

If you mix oil and water together, will these two substances dissolve into each other?
Would you be able to separate this mixture?
If so, how would you do that?

Answer 10

No, they will not dissolve into each other.

Yes, you can separate the mixture.

You can separate the mixture by slowly decanting the oil into another container.

Question 11

There is a glass with water and oil.
Is this mixture a homogeneous or heterogeneous mixture?

Answer 11

heterogeneous mixture

Question 12

When a solid turns into a liquid, we call it________.

Answer 12

melting

Question 13

When a substances dissolves into another, we call it a ________.

Answer 13

solution

Question 14

True or false:
Melting and dissolving are not the same process.

Answer 14

True

Question 15

Air is a mixture of different gasses.
Name the gasses that make up our air.

Answer 15

Oxygen
Nitrogen
Carbon dioxide

Question 16

Which gas makes up 78% of our air?

Answer 16

Nitrogen

Question 17

Which gas makes up 20.9% of clean air?

Answer 17

Oxygen

Question 18

Which gas makes up 0.03% of our air?

Answer 18

Carbon dioxide