Vidaara.orgClass 7 · Mathematics
CodeVID-M7-WS
Physical and Chemical Changes — Practice Worksheet
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Choose the correct option (A, B, C or D) for each question.
- The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each)
25 × 1 = 25 marks
1.
In a physical change, the number of new substances formed is:
- A.One
- B.Two
- C.None
- D.Many
2.
Which of the following is a physical change?
- A.Burning of paper
- B.Melting of ice
- C.Rusting of iron
- D.Cooking of food
3.
Most physical changes are:
- A.Irreversible
- B.Reversible
- C.Explosive
- D.Permanent
4.
When sugar dissolves in water, the sugar can be recovered by:
- A.Burning
- B.Evaporating the water
- C.Freezing only
- D.Adding acid
5.
Dissolving salt in water is best described as a:
- A.Chemical change
- B.Physical change
- C.Combustion
- D.Neutralisation
6.
In a chemical change, the substances formed are:
- A.The same as before
- B.One or more new substances
- C.Always reversible
- D.Only changed in shape
7.
A chemical change is also called a:
- A.Physical change
- B.Chemical reaction
- C.State change
- D.Mixture
8.
Chemical changes are usually:
- A.Easily reversible
- B.Irreversible
- C.Only physical
- D.Temporary
9.
Which of the following is a chemical change?
- A.Melting of butter
- B.Souring of milk into curd
- C.Tearing of paper
- D.Dissolving sugar
10.
Burning of fuel gives out energy mainly in the form of:
- A.Heat and light
- B.Sound only
- C.No energy
- D.Magnetism
11.
The bubbling seen when baking soda is added to vinegar is a sign called:
- A.Change in colour
- B.Evolution of a gas
- C.Formation of a precipitate
- D.Change in shape
12.
An insoluble solid that appears when two solutions are mixed is called a:
- A.Solution
- B.Precipitate
- C.Mixture
- D.Gas
13.
The browning of a freshly cut apple is a sign of chemical change known as a:
- A.Change in colour
- B.Gas evolution
- C.Temperature change
- D.State change
14.
A reaction that makes its container feel warm shows a sign of chemical change called a:
- A.Change in smell
- B.Change in temperature
- C.Precipitate
- D.Colour change
15.
Which of the following is NOT necessarily a sign of a chemical change?
- A.Formation of a precipitate
- B.Evolution of a gas
- C.Bubbles from boiling water
- D.Change in colour
16.
Rusting of iron requires the presence of:
- A.Water only
- B.Oxygen only
- C.Both water and oxygen
- D.Neither water nor oxygen
17.
Rusting of iron is an example of a:
- A.Physical change
- B.Chemical change
- C.Change of state
- D.Reversible change
18.
Coating iron with a layer of zinc to prevent rusting is called:
- A.Painting
- B.Galvanisation
- C.Crystallisation
- D.Neutralisation
19.
Iron objects rust faster in areas that are:
- A.Dry and cold
- B.Humid and coastal
- C.Sealed and airless
- D.Free of moisture
20.
A rust-resistant alloy used for cutlery is:
- A.Pure iron
- B.Stainless steel
- C.Copper
- D.Lead
21.
Crystallisation is used to obtain pure ______ of a substance from its solution.
- A.Gases
- B.Crystals
- C.Liquids
- D.Mixtures
22.
Crystallisation is an example of a:
- A.Chemical change
- B.Physical change
- C.Irreversible change
- D.Combustion
23.
To obtain large, well-formed crystals, a hot saturated solution should be:
- A.Cooled slowly
- B.Cooled quickly
- C.Boiled again
- D.Frozen instantly
24.
During crystallisation, impurities mostly:
- A.Form the crystals
- B.Remain in the liquid
- C.Disappear completely
- D.Turn into gas
25.
Common salt is obtained from seawater by:
- A.Galvanisation
- B.Evaporation (crystallisation)
- C.Neutralisation
- D.Rusting
Answer Key
Section A — Multiple Choice (1 mark each)
- (C) None
- (B) Melting of ice
- (B) Reversible
- (B) Evaporating the water
- (B) Physical change
- (B) One or more new substances
- (B) Chemical reaction
- (B) Irreversible
- (B) Souring of milk into curd
- (A) Heat and light
- (B) Evolution of a gas
- (B) Precipitate
- (A) Change in colour
- (B) Change in temperature
- (C) Bubbles from boiling water
- (C) Both water and oxygen
- (B) Chemical change
- (B) Galvanisation
- (B) Humid and coastal
- (B) Stainless steel
- (B) Crystals
- (B) Physical change
- (A) Cooled slowly
- (B) Remain in the liquid
- (B) Evaporation (crystallisation)
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