A plot of temperature versus heat energy for a given quantity of water

1.	A plot of temperature versus heat energy for a given quantity of water is shown below. What can be inferred studying it?Temperature versus heat for water at one standard atmospheric pressure (not to scale)
Answer» Inferences: 1. When heat is added (or removed) during a change of state, the temperature remains constant. 2. Also the slopes of the phase lines are not all the same, which indicates that specific heats of the various states are not equal. 3. For water, the latent heat of fusion and vaporisation are L_f = 3.33 × 10⁵J kg^-1 and L_v = 22.6 × 10⁵ J kg^-1 respectively, i.e., 3.33 × 10⁵J of heat is needed to melt 1 kg of ice at 0 °C and 22.6 × 10⁵J of heat is needed to convert 1 kg of water to steam at 100 °C. 4. This means, steam at 100 °C carries 22.6 × 10⁵ J kg^-1 more heat than water at 100 °C.

A plot of temperature versus heat energy for a given quantity of water is shown below. What can be inferred studying it?Temperature versus heat for water at one standard atmospheric pressure (not to scale)

Answer»

Inferences:

1. When heat is added (or removed) during a change of state, the temperature remains constant.

2. Also the slopes of the phase lines are not all the same, which indicates that specific heats of the various states are not equal.

3. For water, the latent heat of fusion and vaporisation are L_f = 3.33 × 10⁵J kg^-1 and L_v = 22.6 × 10⁵ J kg^-1 respectively,

i.e., 3.33 × 10⁵J of heat is needed to melt 1 kg of ice at 0 °C and 22.6 × 10⁵J of heat is needed to convert 1 kg of water to steam at 100 °C.

4. This means, steam at 100 °C carries 22.6 × 10⁵ J kg^-1 more heat than water at 100 °C.