Physical Chemistry Answers

An engine containing 2 kg air as working substance is initially at 1 atm and 27 0C.

The system undergoes isochoric process to a point where pressure of the system is 2

atm. At this point heat is transferred to the air untill the volume doubles. Calulate

the total workdone and the amount of heat transferred to the air.

Gas is compressed slowly and isothermally at 300K from 1 bar to 8 bar. Calculate

the work done using the given state of equation. (B = -5.397 X 10-6 m3

/mol)

(note: volume at each stage should be near to the ideal gas volume)

PV

RT = 1 +

B

V

An engine containing 2 kg air as working substance is initially at 1 atm and 27 degree celcius.

The system undergoes isochoric process to a point where pressure of the system is 2

atm. At this point heat is transferred to the air untill the volume doubles. Calulate

the total workdone and the amount of heat transferred to the air.

In a reversible compression, 1 mol of ideal gas in a piston –cylinder device undergoes

a pressure increase from 1 bar to pressure P and temperature increases from 500 K

to 1000 K. The compression path is described by PV^1.5 = constant. Heat capacity is

given by Cp*/R = 3.3 + 0.63 X 10-3 T. Calculate the final pressure and heat

transferred.

Using the following data, calculate the amount of energy by which benzene is more

stable as compared to one Kekule structure:

∆fH*=(methane, g) = −84.85 kJ/mol

∆fH*=(ethane, g) = −94.85 kJ/mol

∆fH*=(ethylene, g) = −65.35 kJ/mol

∆fH*=(benzene, g) = −98.45 kJ/mol

C (graphite) → C (g); ∆H* = 714.39 kJ/mol

H2(g) → 2H(g) ∆H* = 435.89 kJ/mol

(here '*' denotes degree sign)