Describe the changes to the kinetic energy, the potential energy and the total internal energy of its molecules as ice melts into water.

Ice melts at $0°\mathrm{C}$.

 

Describe the changes to the kinetic energy, the potential energy and the total internal energy of the molecules of a block of ice as: 

The temperature of the water rises from $0°\mathrm{C}$to room temperature. 

The so-called 'zeroth law of thermodynamics' states that if the temperature of body $\mathrm{A}$ is equal to the temperature of body $\mathrm{B}$ and 

the temperature of body $\mathrm{B}$ is the same as body $\mathrm{C}$, then the temperature of body $\mathrm{C}$ equals the temperature of body $\mathrm{A}.$ 
Explain, in terms of energy flow, why the concept of temperature would be meaningless if this law was not obeyed.

. Figure shows a fixed mass of gas that undergoes a change from $\mathrm{A}$ to $\mathrm{B}$ and then to $\mathrm{C}.$

 During the change from$\mathrm{A}$ to$\mathrm{B}, 220 \mathrm{J}$of thermal energy (heat) is removed from the gas. Calculate the change in the internal energy of the gas.

Figure shows a fixed mass of gas that undergoes a change from $\mathrm{A}$ to $\mathrm{B}$ and then to $\mathrm{C}.$

During the change from $\mathrm{B}$ to C, the internal energy of the gas decreases by $300 \mathrm{J}$. Using the first law of thermodynamics explain how this change can occur. 

When a thermocouple has one junction in melting ice and the other junction in boiling water it produces an e.m.f. of $63\mathrm{\mu V}.$. 

What e.m.f. would be produced if the second junction was also placed in melting ice?