Rusting of iron is a chemical change because
It is temporary
It can be cleaned and the original substance recovered
It is a slow reaction
A new substance is formed
Burning of coal in air is a:
Physical change
Chemical change
Reversible change
Edothermic reaction
The process of heating a liquid to a high temperature and rapidly cooling it to kill bacteria is called
Pasteurization
Chlorination
Bacterial infection
Sublimation
Halley comet revolves around the sun once in every 76 years. This is a
Photochemical change
Periodic change
Irreversible change
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
Physical changes require _________ energy than chemical changes
Less
More
Equal amount of
Very high amount of
Study of photo-chemical reaction is called:
Photonics
Photography
Photochemistry
All of these
A ball lying on the groung does not move on its own because
It has inertia
It has no energy
It does not want to move
All
Which of the following is not a reversible change ?
Heating of water to steam
Cooking of egg to scrambled eggs
Heating of wax to molter wax
Cooling a cake
Choose the correct statement from the following
Catalysts do not change during a chemical change
All chemical changes are irreversible
A reversible change is always a physical change
Chemical changes always release energy
