5) A container of volume 60L contains 1.8 kg of nitrogen gas N2 with molar mass M = 28 g /
mol. The pressure is 500 kPa when the amount of heat Q= 26 kJ is supplied in an isochoric
process. Calculate the temperature before the energy supply and the temperature increase.
6) Anideal freezer can be seen as a reverse Carnot machine operating between temperatures
-18c and 23c. The freezer draws 200 watts. Assume that all the electrical power applied goes to
mechanical work on the gas and that the time for a cycle is 0.080s. Determine the freezer's
COP and the amount of heat that the freezer gives to the room it is in for 10 minutes. Calculate
the amount of heat taken from the freezer compartment during a cycle.
7) Six moles of a monoatornic ideal gas (y = 5/3) undergo a cyclic process a - b - c-> a as
shown in the diagram below. One of the sub-processes is adiabatic and one is isothermal. In
points a and c the volumes Va = 25 L and Vc = 125L
State which process is isothermal and determine its temperature. Calculate the pressure in c.
Calculate the volume exactly at point b. Calculate the amount of heat supplied / removed in the
isothermal process. Calculate the amount of heat supplied / removed in the isobaric process
and the work of the gas during a cycle.
8) A heater operates between two isotherms with the temperatures Tc = 280K and Thin the
process a- b - c-> d as the figure below shows. The gas is atomic and consists of n moles
Determine the number of moles n and the temperature TH. Determines in which sub-processes
heat is applied. Calculate the work done during a cycle and the efficiency of the machine
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