Name: Freezing of Water
Uploaded: 2019-07-19
Duration: 3 min 31 s
Description: Freezing, also known as solidification, is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. Let's watch and study.

Question

Draw and explain how the change of state of ice into steam can be represented graphically.

Accepted Answer

The process of change of a substance from one state to another by changing temperature and pressure is called its change of state.

When we take $1 g$ of ice and apply heat on it at a constant rate, the different stages of its change of state can be better understood by the temperature-heat graph as shown above. Its different parts are explained below :

$A B$ part : Temperature of ice rises from $— 5 ° C$ to $0 ° C$ . The amount of heat gained by ice can be calculated using the formula $H = m s t$ .
$B C$ part : Melting of ice starts at $B$ and ends at $C$ , but the temperature remains constant. So, the amount of heat gained can be calculated by the formula $H = m L$ .
$C D$ part : Temperature of water rises from $0 ° C$ to $100 ° C$ . In this part, formula $H = m s t$ is applicable to calculate the required amount of heat.
$D E$ part : In this part, water at $100 ° C$ changes into steam at $100 ° C$ . $H = m L$ formula is applicable as the temperature remains the same.
We can see that the part $B C$ is shorter than the part $D E$ . The reason is that the specific latent heat of melting of ice ( $80 cal g^{- 1}$ ) is less than the specific latent heat of vaporisation of water ( $537 cal g^{- 1}$ ). Likewise, if heat is removed the reverse changes of state will take place.

Draw and explain how the change of state of ice into steam can be represented graphically.

Important Questions on Heat

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