Solution: Determining the Change in Internal Energy Since it is an isochoric process, change in internal energy is equal to the supplied heat. ΔU1=Q1=92nRT1.

Increasing E: (1) eating food (taking in energy); (2) going to a hot bath/sauna (heat is absorbed by the body)… Decreasing E: (1) exercising (heat is released and the body does work); (2) going outside during winter (heat is released by the body into the environment)

• The internal energy can be changed by changing the temperature or volume of the object without changing the amount of particles in the object.
• Temperature: If the temperature of a system rises, the molecules will travel quicker, therefore have more kinetic energy and so the Internal Energy will increase.

The change in internal energy for any cycle is always zero because the system returns to its original state, and the area of the enclosed region on the P-V diagram is the net work done by the gas in the cycle.

Therefore, isothermal expansion is the increase in volume under constant-temperature conditions. During isothermal conditions, the change in internal energy ΔU is 0 for only an ideal gas, so efficient work done is entirely transformed into efficient heat flow.

It is not generally true that ΔU=0 in an isothermal process. An ideal gas by definition has no interactions between particles, no intermolecular forces, so pressre change at constant temperature does not change internal energy. For an ideal gas, in an isothermal process, ΔU=0=Q−W, so Q=W.

An isothermal process is any process in which the temperature of the system remains constant. According to the First Law of Thermodynamics, the change in internal energy of a closed system is equal to the heat transferred into the system plus the work done by the system.