During a physical change, new substances are formed.
True
False
Energy changes always occur during a chemical change.
True
False
Rusting of iron takes place in the presence of water only.
True
False
Rusting of iron can be prevented by wrapping iron articles in paper.
True
False
Click the correct answer.
Crystallization is a process of obtaining which of the following?
Pure solids only
Pure liquids only
Pure gas only
All of these
Observe the following two changes. Change A: Biogas is produced by decomposition of animal and plant waste by anaerobic bacteria. Change B: Biogas is burnt as other fuels. Which of these is a chemical change?
Change A
Change B
Both Change A and B
None of these
Which of the following prevents rusting of iron?
Galvanizing
Electroplating
Alloying
All of these
LPG (Liquefied Petroleum Gas) is used as fuel in kitchen. It exists as a liquid in a cylinder. When it comes out of the cylinder, it becomes a gas. Which of the following is true about it?
Physical change
Chemical change
Both physical and chemical change
None of these
Which of the following burns with a pop sound?
Sulphur dioxide
Oxygen
Hydrogen
Carbon dioxide
Click each box on the left and then click the matching box on the right.
Match the Columns
Brown flaky layer
Formation of new substance
Change in state
Heat energy is absorbed
Heat energy is evolved
Rust
Chemical change
Physical change
Endothermic reaction
Exothermic reaction
Click the correct answer.
When baking soda is added to vinegar,
gas is produced.
oxygen
nitrogen
carbon dioxide
Hydrogen
Dissolving sugar in water is a
change.
chemical
physical
endothermic
exothermic
The process of depositing a layer of zinc on iron is called
.
rusting
precipitating
galvanizing
electroplating
Crystals of pure substances are obtained from their solutions by
.
