Thermodynamics Terms

? ? ? ? ? ? = (- 635.09) + (- 393.51)-(-,1206.92)
? ? ? ? ? ? =

According to the first law of thermodynamics: where: - is the change in internal energy,
- is the heat added to the system, and
- is the work done by the system on the surroundings. Here, and . Thus: Since the work is done on the surroundings, the change in internal energy is -150 cal. Thus, the correct answer is Option (B).

The melting of ice is a phase transformation that occurs when solid ice changes into liquid water at constant pressure and temperature. The melting point of ice is 0°C (273 K), which is the standard condition for phase changes. Therefore, both (a) and (b) are correct. Thus, the correct answer is Option (D).

The difference between heat capacities at constant pressure and constant volume is equal to the gas constant . This is derived from the thermodynamic relationship for ideal gases, where: Where is the heat capacity at constant pressure and is the heat capacity at constant volume. Thus, the difference is .