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
Cooking of rice is an example of:
Irreversible change
Endothermic reaction
Exothermic change
Reversible change.
When nitrogen reacts with hydrogen under high temperature and pressure ammonia, which is also a gas is formed. This is an example of:
Chemical combination
Chemical decomposition
Physical change
Oxidation
The growth of seedlings in a crop is a:
Undesirable change
Desirable change
Reversible change
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
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
Melting of ice is an example of:
Exothermic reaction
Which of the following is the easiest to change?
The colour of your hair
The shape of your face
The colour of your eyes
Both A & C
A chemical reaction in which energy is liberated is called:
Photo chemical reaction
Identify the substance that evaporates at room temperature:
Water
Oil
Kerosene
Ammonium chloride