Physical and Chemical Changes
Physical and Chemical Changes: Overview
This topic explains the difference between physical and chemical changes of a matter. Chemical characteristics of oil and water are described here. An example of burning is also illustrated to explain the concept.
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 |
_____ _____ |
Which of the following statement is incorrect about Crystallisation?
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
Burning of coal
A chemical change is _____, _____ and produces _____. (temporary/permanent, reversible/Irreversible, new substance/no new substance)
Identify the following change as Physical or Chemical.
Recycling of plastics
Identify the following changes as Physical or Chemical.
Combustion of petrol and diesel.
Identify the following changes as Physical or Chemical.
Running of steam engine.
Identify the following change as Physical or Chemical.
Browning of apples
Identify the following changes as Physical or Chemical.
Burning of camphor
