Question

State whether true or false:
To freeze water into ice, energy must be removed.

Answer 1

Hint: Freezing is a phenomenon in which the state of the liquid changes into a solid. Water mainly exists in the three forms of the state which are solid, liquid, and gas. Water is one of the substances which shows this property. It can exist in water(liquid), steam(gas), and ice(solid).

Complete step by step answer
The existence of water in different states depends on the energy of the molecules residing in it. The molecules gain or lose energy which results in the change in temperature of the molecules. Hence the change in temperature results in the change in states. The speed and randomness of the molecules depend on the temperature. So when the temperature of the substance changes, the speed of its molecules also changes. As a result, it changes its states also.
The molecules of water are attracted by a molecular force between them. When energy is provided to the molecules of a substance like water. The temperature of the molecules increases which results in the breaking of the attractions between the molecules and as a result the water starts changing into steam which is a gas state. This phenomenon is called evaporation.
Similarly when energy is removed from the water by lowering its temperature then the speed of the molecules decreases and the force of attraction also increases and the molecules start making a strong bond due to this force. Hence the water starts converting into ice. This phenomenon is called freezing.
Hence it is true that to freeze water, energy is removed from it.

Note
When the energy is removed from steam which is a gas state of water, it starts changing into the liquid form because of the decrease in the temperature of the molecules. This phenomenon is called condensation. This phenomenon is observed in our daily life. All this phenomenon plays an important role in our natural water cycle.