Separation of Substances

1. What is Winnowing ?

• A method used to separate the components of a mixture which are different sizes substances.

• The practice of separating undesirable solid substances and impurities from useful solids by hand.

• A method used to separate lighter components of a mixture from the heavier ones by wind or by blowing air.

2. What means to cut the crop from the field?

• Threshing

• Winnowing

• Harvesting

• Sieving

3.How do we separate grains from stalks?

• Sieving

• Threshing

• Winnowing

• Handpicking

4.When do we mostly use handpicking?

• When we separate stones from rice

• When we separate water from sand

• When we separate sugar from water

• ALL of the above

5.A solution in which no more solute can be added is called

• True Solution

• Unsaturated solution

• Saturated solution

• Mixture

6. The density of water is 1g/cc. Mercury is denser and kerosene is less dense than water. None of the liquids mix with each other. What will a jar that has 20 ml of water, 10 ml of mercury and 30 ml of kerosene look like?

• A

• B

• C

• D

7. State whether true /false.

Oil layers in the oceans blocks the air from entering the water and affects aquatic life.

• True

• False

8. State whether true /false.

Immiscible liquids form different layers due to the difference in density of the liquids.

• True

• False

State true or false

9.The solubility of gases in water increases with increase in temperature.

• True

• False

10. A student measures 5 grams of sugar into 50 milliliters of water in a flask.

Which of the following should the student do to help the sugar dissolve more quickly into the water?

• place the flask in a refrigerator.

• place a stopper in the top of the flask

• add more water to the mixture

• gently swirl the mixture in the flask