Chemical Engineering Thermodynamics - Study Mode

[#246] C v for an ideal gas
Correct Answer

(D) Is independent of both pressure and volume

Explanation

Solution: For a real gas the $${C_V}$$ has an weak relationship with volume and pressure in many cases this relation can be neglected and depends only on temperature whereas for ideal gases $${C_V}$$ is solely dependent on temperature. The usually relationship is given by $${C_V} = a + bT + C{T^2} + ,,...$$ xa0 xa0 and these constants $$a, b, c…$$ varies from gas to gas.

[#247] The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is
Correct Answer

(A) Less

Explanation

Solution: The COP of a domestic air conditioner is less than that of household refrigerator because the work input in case of domestic air conditioner is higher than refrigerator $${x08f{cop}} = frac{{{ ext{desired output}}}}{{{ ext{work input}}}}.$$

[#248] The gas law (PV = RT) is true for an __________ change.
Correct Answer

(C) Both A & B

Explanation

Solution: The gas law PV = RT is an ideal gas law and can be applied to an ideal gas that is undergoing any changes (isothermal, adiabatic etc.).

[#249] If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
Correct Answer

(D) 200

Explanation

Solution: Since, pressure and volume are inversely proportional on halving the pressure the volume will be doubled. Hence volume = 200 c.c.

[#250] Free energy change of mixing two liquid substances is a function of the
Correct Answer

(D) All of the above

Explanation

Solution: $$Delta {g^{mix}} = RTsum
olimits_{i = 0}^2 {{n_i}ln {x_i}} $$ Hence, we can say free energy is dependent on concentration, temperature, quantities of constituents.