Enthalpy

Q. Consider the following liquid – vapour equilibrium.
$Liquid\rightleftharpoons Vapour$
Which of the following relations is correct?

1. $\frac{dInP}{d{T}^2}=\frac{-\Delta H_v}{T^2}$
2. $\frac{dInP}{dT}=\frac{-\Delta H_v}{RT}$
3. $\frac{dInG}{d{T}^2}=\frac{\Delta H_v}{R{T}^2}$
4. $\frac{dInP}{dT}=\frac{\Delta H_v}{R{T}^2}$

Q. One mole of an ideal gas at 300 K in thermal contact with surroundings expands isothermally from 1.0L to 2.0L against a constant pressure of 3.0 atm. In this process, the change in entropy of surroundings $\left(\Delta S\right)in{T}^{-1}$ is (1 L atm = 101.3J)

1. -5.763
2. 5.763
3. 1.013
4. -1.013

Q. Internal energy change for combustion of ethanol is 416.5 $kJmo{l}^{-1}$. The calorific value of ethanol at 300 K in $\left(kJ\right)$ is (Take R= 25/3 J/molK)

Q. The enthalpy change involved in the oxidation of glucose is 2880 kJ/mol. $25\%$ of this energy is available for muscular work. If 100 kJ of muscular work is required to walk 1 km, calculate the maximum distance that can be covered by a person who as consumed 120 g of glucose

1. 7.9 km
2. 9.7 km
3. 4.8 km
4. 8.4 km

Q. Which of the following is always negative for exothermic reaction?

1. $Noneofthese$
2. $\Delta H$
3. $\Delta S$
4. $\Delta G$

Q. For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, pick the correct option:

1. $\Delta U<0,w=0$
2. $\Delta U=0,w<0$
3. $\Delta U>0,w=0$
4. $\Delta U<0,w>0$

Q.

Consider an endothermic reaction $X\to Y$ with the activation energies $E_b$ and $E_f$ for the backward and forward reactions, respectively. IN general

1. There is no definite relation between E_b and E_f

2. E_b < E_f

3. E_b = E_f

4. E_b > E_f

Q. Point out the wrong statement in relation to enthalpy

1. It is a state function
2. It is an intensive property
3. Its value depends upon the amount of substance in the system
4. It is independent of the path followed for the change

Q. One mole of an ideal gas undergoes a change in state from (2 atm, 3L, 95K) to (4 atm, 5L, 245K). Calculate the change in enthalpy if $\Delta U=30L-atm$:

1. Cannot be predicted as pressure is not constant
2. 40L - atm
3. 42.3L - atm
4. 44L - atm

Q. For the isothermal expansion of an ideal gas

1. E increases but H decreases
2. H increases but E decreases
3. E and H are unaltered
4. E and H increases