The cells used in a wrist watch undergo:
Physical change
Periodic change
Chemical change
None
Which of the following is a feature of physical change?
It is reversible
It is temporary
No new substance is formed
All of these
A chemical reaction in which energy is liberated is called:
Exothermic reaction
Endothermic reaction
Photo chemical reaction
We keep food at low temperature in a refrigerator because it:
Saves money
Makes food more tastier
Kills bacteria present in the food
In fashionable to keep the food in the refrigerator
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
Burning of a match stick is a/an:
Both B & C
Identify the substance that evaporates at room temperature:
Water
Oil
Kerosene
Ammonium chloride
Dissolving salt in water is a/an:
Endothermic change
Exothermic change
Both A and B
Chemical combination
A seed growing into a tree is an example of:
Slow physical change
Fast periodic change
Slow natural change
Man made reversible change
The making of a ring from gold is a ______ change and making a statue from wood is a _______ change.
Irreversible, reversible
Reversible, irreversible
Irreversible, irreversible
Reversible, reversible
