Physical and Chemical Changes
Physical and Chemical Changes: Overview
This topic covers concepts, such as, Physical and Chemical Changes, Physical Changes, Nature of Interconversion of States, Difference in Cooking Oil and Water, Chemical Changes, Chemical Reaction & Changes in Burning of Candle etc.
Important Questions on Physical and Chemical Changes
Cooking oil and water are separated by distillation method.

What is the difference between the chemical properties of oil and water?

Cooking oil and water are separated by _____.

How do you separate cooking oil and water?

How do you separate oil from water?

Melting of ice is a physical and chemical change?

What is a chemical change? Give one example.

Open a soda water bottle and place a red and blue litmus paper one by one near the gas coming out of the bottle. Also put both of the litmus paper inside the solution of soda water and observe and note the colour changes of the litmus paper.
Take baking soda in a spoon and test it with wet litmus paper(blue/red). Now heat baking soda in a boiling tube, bring the litmus paper(blue/red) near the gas liberated and note the changes.
Note acidic/basic nature of soda water and baking soda according to the colour change in litmus paper in the table below.
S.No. | Substance/Compound | Test with litmus paper | Acidic/basic nature |
1. | Soda water |
(a) Liberated gas (b) In soda water |
_____ ______ |
2. | Baking soda |
(a) In baking soda (b) Liberated gas |
_____ _____ |

Curdling of milk is an example of _____ change.

State the type of chemical reaction.

State the type of chemical reactions.

Fill in the blank.
Heating of zinc oxide is a _____ change.

One of the chemical properties of cooking oil is that it is _____.

A water molecule consists of two hydrogen atoms bonded to an oxygen atom, whereas cooking oil consists of fatty acids.

Water is acidic in nature.

Cooking oil has a low flash point, making it highly flammable.

Classify the following reaction into physical and chemical change
Dissolving sugar in water

Classify the following reaction into physical and chemical change
Hammering and converting into a thin sheet of an aluminium piece

Classify the following reaction into physical and chemical change
Burning of coal

A chemical change is _____, _____ and produces _____. (temporary/permanent, reversible/Irreversible, new substance/no new substance)
