An ideal gas absorbs 2000 cal of heat from a heat reservoir and does mechanical work equivalent to
4200 J. The change in internal energy of the gas is:

1. 3000 cal

2. 2000 cal

3. 1500 cal

4. 1000 cal

For an ideal gas four processes are marked as 1, 2, 3 and 4 on P-V diagram as shown in figure. The amount of heat supplied to the gas in the process 1, 2, 3 and 4 are Q₁, Q₂, Q₃ and Q₄ repectively, then correct order of heat supplied to the gas is

[AB is process-1, AC is process-2, AD is adiabatic process-3 and AE is process-4]

1. $Q_1>Q_2>Q_3>Q_4$

2. $Q_1>Q_2>Q_4>Q_3$

3.  $Q_1>Q_4>Q_2>Q_4$

4. $Q_1<Q_2<Q_3<Q_4$

The latent heat of vapourisation of water at ${25}^{\circ }C$ is 10.5 kcal mol^-1 and the standard heat of formation of liquid water is -68.3 kcal. The enthalpy change of the reaction

$H_2\left(g\right)+\left(1/2\right)O_2\left(g\right)\to H_{2}O\left(g\right)$ is therefore,

1. -57.8 kcal

2. -78.8 kcal

3. 78.8 kcal

4. -47.3 kcal

Which of the following thermodynamic quantities is an outcome of the second law of thermodynamics?

1. Work

2. Enthalpy

3. Internal energy

4. Entropy

From the following data of $∆H$, of the following reactions,

$C\left(s\right)+\frac{1}{2}{O}_2\to CO\left(g\right) ;∆H=-110 kJ$
$C\left(s\right)+H_{2}O\to CO\left(g\right)+H_2\left(g\right) ;∆H=132 kJ$

What is the mole composition of the mixture of steam and oxygen on being passed over coke at 1273 K, keeping temperature constant.

1. 0.5 : 1

2. 0.6 : 1

3. 0.8 : 1

4. 1 : 1

State which of the following statements is true ?

1. First law of thermodynamics is not adequate in predicting the direction of the process.

2. In an exothermic reaction, the total enthalpy of the products is greater than that of reactants.

3. The standard enthalpy of diamond is zero at 298 K and 1 atm pressure.

4. It is possible to calculate the value of $∆H$ for the reaction $H_2\left(g\right)+B{r}_2\left(l\right)\to 2HBr\left(g\right)$ from the bond enthalpy data.

The intermediate SiH₂ is formed in the thermal decomposition of silicon hydrides. Calculate $∆H_f^{\circ }$ of SiH₂ given the following reactions

$S{i}_2{H}_6\left(g\right)+H_2\left(g\right)\to 2Si{H}_4\left(g\right); ∆H^{\circ }=-11.7 kJ/mol$
$Si{H}_4\left(g\right)\to Si{H}_2\left(g\right)+H_2\left(g\right); ∆H^{\circ }=+239.7 kJ/mol$
$∆H_f, S{i}_2{H}_6\left(g\right)=+80.3 kJ mo{l}^{-1}$

1. 353 kJ/mol

2. 321 kJ/mol

3. 198 kJ/mol

4. 274 kJ/mol

A certain vessel X has water and nitrogen gas at a total pressure of 2 atm. and 300 K. All the contents of the vessel are transferred to another vessel Y having half the capacity of the vessel X. The pressiure of N₂ in this vessel was 3.8 atm. at 300 K. The vessel Y is heated to 320 K and the total pressure observed was 4.32 atm. Calculate the enthalpy of vapourisation of water assuming it to be independent of temperature. Also assume the volume occupied by the gases in a vessel is equal to the volume of the vessel.

1. 39.637 kJ mol^-1

2. 19.531 kJ mol^-1

3. 396.37 kJ mol^-1

4. 3.9127 kJ mol^-1

For a reaction, $A+B\to AB, ∆c_P$ is given by the equation $40+5\times {10}^{-3} T J{K}^4$ in the temperature range 300-600 K. The enthalpy of the reaction at 300 K is -25.0 KJ. Calculate the enthalpy of the reaction at 450 K.

1. -10.12 kJ

2. -28.32 kJ

3. -18.72 kJ

4. -8.21 kJ

Given that the heat of combustion of ethylene at 17°C and constant volume is -332.19 kcal, what is the value of the heat of combustion at constant pressure, assuming water is in the liquid state?

1. -131.25 k cals

2. -412.23 k cals

3. -534.12 k cals

4. -333.35 k cals