On decreasing temperature, a liquid turns into solid. This is:
Condensation
Melting
Freezing
Sublimation
Which of the following is not a reversible change?
Heating of water to steam
Cooking of egg to scrambled eggs
Heating of wax to molten wax
Cooling a cake
Dissolving salt in water is a/an:
Endothermic change
Exothermic change
Both A and B
Chemical combination
Melting of ice is an example of:
Exothermic reaction
Endothermic reaction
Chemical decomposition
When a solid directly turns into gaseous state, it is called:
Polymerisation
Identify the substance that evaporates at room temperature:
Water
Oil
Kerosene
Ammonium chloride
The cells used in a wrist watch undergo:
Physical change
Periodic change
Chemical change
None
Burning of a match stick is a/an:
Both B & C
Cloud seeding is a technique used to induce rain that was first used by USA in 1946. It has also been done in Karnataka and other places in India. What is it ?
An agricultural practice that depends on clouds
Introduction of particles in clouds to increase condensation
Making clouds and placed them in the sky
Trimming the clouds into seed like structures
A chemical reaction in which energy is liberated is called:
Photo chemical reaction