The cells used in a wrist watch undergo:
Physical change
Periodic change
Chemical change
None
When liquids are heated, they turn into gases. The yellow egg yolk present inside the egg is a liquid but when it is heated, it changes into an omelet which is solid, why?
Sometimes, liquids turn into solids
Omelet does not follow the above rule
Strictly speaking, the rule does not apply to complex mixtures and egg yolk is a complex mixture
A seed growing into a tree is an example of:
Slow physical change
Fast periodic change
Slow natural change
Man made reversible change
Melting of ice is an example of:
Exothermic reaction
Endothermic reaction
Chemical combination
Chemical decomposition
A chemical reaction in which energy is liberated is called:
Photo chemical reaction
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
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
In an endothermic reaction:
Energy is released
Energy is absorbed
Energy is neither released nor absorbed
Energy is not required
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
On decreasing temperature, a liquid turns into solid. This is:
Condensation
Melting
Freezing
Sublimation
