The properties of a system, during a reversible constant pressure non- flow process at P=1.6 bar, changes from V,=0.3m'/kg, t;=20°C to
V=0.55m²/kg, tz=260°C. The specific heat of the fluid is given by
Cp=1.5+75/(t+45) kJ/kg°C where t is in °C.
Determine:
i. Heat added/kg
ii. Change in internal energy/kg
iii. Change in enthalpy/kg

Apreheater involves the use of condensing steam at 100°c on the inside of a bank of tubes to heat air that enters at 1 atm and 25°c. the air moves at 5 m/s in cross flow over the tubes. each tube is 1 m long and has an outside diameter of 10 mm. what is the minimum value of nl needed to achieve an outlet temperature of t 75 c? what is the corresponding pressure drop across the tube bank?

An air-conditioning system consists of a heating section and an evaporative cooler. air enters the heating section at 10°c and 70 percent relative humidity at a rate of 30m^3/min, and it leaves the evaporative cooler at 20°c and 60 percent relatively humidity. if the air conditioning system operates at a total pressure of 98 kpa, determine (a) the temperature and relative humidity of the air when it leaves the heating section, (b) the rate of heat transfer in the heating section, and (c) the rate of water added to air in the evaporative cooler

Amixture of gases consists of 0.4 kg of oxygen, 0.7 kg of carbon dioxide, and 0.2 kg of helium this mixture is maintained at 100 kpa and 27°c. determine: (a) the apparent molecular weight of this mixture the volume it occupies (b) the partial volume of the oxygen, and (c) (d) the partial pressure of the helium