+2 votes
in JEE by kratos

A cylinder is fitted with a freely move able piston of area 1.20 × 10–2 m2 and negligible mass. The cylinder below the piston is filled with a gas. At state 1, the gas has volume 1.50 × 10–3 m3 , pressure 1.02 × 105 Pa, and the cylinder is in contact with a water bath at a temperature of 0°C. The gas is then taken through the following four-step process.

• A 2.50kg metal block is placed on top of the piston, compressing the gas to state 2, with the gas still at 0°C.

• The cylinder is then brought in contact with a boiling water bath, raising the gas temperature to 100°C at state 3.

• The metal block is removed and the gas expands to state 4 still at 100°C.

• Finally, the cylinder is again placed in contact with the water bath at 0°C, returning the system to state 1.

a. Determine the pressure of the gas in state 2.

b. Determine the volume of the gas in state 2.

c. Indicate below whether the process from state 2 to state 3 is isothermal, isobaric, or adiabatic.

Isothermal Isobaric _____Adiabatic Explain your reasoning.

d. Is the process from state 4 to state 1 isobaric? Yes No

Explain your reasoning.

e. Determine the volume of the gas in state 4.

1 Answer

+3 votes
by kratos
 
Best answer

a. The additional pressure comes from the weight of the added block. ∆P = F/A = mg/A = 2.04 × 103 Pa and P2 = P1 + ∆P = 1.04 × 105Pa

b. A constant temperature, P1V1 = P2V2, or V2 = P1V1/P2 = 1.47 × 10-3m3

c. Since the external pressure and the added weight do not change, the pressure *** constant, therefore the process from state 2 to state 3 is isobaric

d. For similar reasons as stated above, the process from state 4 to state 1 is also isobaric.

e. Comparing state 1 and state 4, which have equal pressures: V1/T1 = V4/T4, giving V4 = V1T4/T1 = 2.05 × 10–3m3.

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