Helium gas is compressed from 16 psia and 85°F to 120 psia at a rate of 10 ft3 /s. Determine the power input to the compressor, assuming the compression process to be isothermal.

In a gasoline engine, the cylinder conditions are 1.2 MPa and 450°C before the combustion and 1900°C after it. Determine the pressure at the end of the combustion process

A cylinder-piston device provided with stops, so that the water supports the weight of the piston, and the force of the atmosphere,It contains water, initially at 300 kPa and 0.5 m3 / kg. The water is heated to a saturated steam condition and the plunger rests on the stops. With the plunger on the stops, the water is heated up to the pressure of 600 kPa. In the P-V and T-V diagrams, with respect to the saturation lines, the process curves go through the initial and final states of the water. On both T-V and P-V diagrams draw the isotherms that pass through both states, and show their values in ° C, in the isotherms. (see img 1)

Air with a mass of 3 kg is heated at a constant volume from a temperature of 25°C to 80°C. The process then takes place at constant pressure so that the gas has a temperature of 150°C. Determine the heat required and the entropy changes that occur during the process. (Air: Cp =1,005 kJ/kg. K and γ = 1.4; and assume Cp does not change against temperature)