Internal Energy

Q.

Internal energy is a state function. Explain?

Q. A system absorbs 500 J of heat and does work of 50J on it surroundings. The change in internal energy is:

1. 450 J
2. 550 J
3. 400 J
4. None

Q. Assertion: Greater is the critical temperature, more difficult is to liquefy the gas. Reason: Stronger are the intermolecular forces lowerwould be the critical temperature of that gas.

Q. The Internal Energy Change ($\Delta U$) of a Process does not depends upon

1. Amount of substance undergoing the change.

2. Temperature

3. Path of the process.

4. Nature of substance undergoing the change.

Q.

Absolute value of internal energy can be easily measured.

1. True

2. False

Q. Explain Heat ( The Internal energy as a state function)

Q. Internal energy is an example of

1. Path function
2. State function
3. Both (a) and (b)
4. None of these

Q. 29.If RMS velocity of a gas is 30\sqrt{}R m/s at 27 ^° C then molar mass of gas is ??

Q. Calculate $\Delta U$ and $\Delta H$ in calories respectively, if one mole of a monoatomic ideal gas is heated at constant pressure of 1 atm from ${25}^{o}C$ to ${50}^{o}C$.

1. $74.5caland124.2cal$
2. $74.5caland49.5cal$
3. $49.7caland-74.5cal$
4. $-49.7caland-74.5cal$

Q. The correct statement during the process of melting of ice or freezing of water is:

1. Both temperature and internal energy changes
2. Temperature doesn't change while internal energy changes
3. Temperature changes while internal energy doesn't change
4. Cannot be predicted

Q. In a thermodynamic process with 2 moles of gas, 30 J of heat is released and 22 J of work is done on the gas. Given that the initial internal energy of the sample was 20 J, the final internal energy is :

1. 72 J
2. 32 J
3. 28 J
4. 12 J

Q. When 1 moe of ice melts at $0^{o}C$ and at constant pressure of 1 atm, 1440 calories of heat are absorbed by the system. The molar volume of ice and water are 0.0196 and 0.0180 litre respectively. Which of the following is correct?

1. $\Delta U\approx \Delta H$
2. $\Delta U=1548cal$
3. $\Delta U=1056cal$
4. None of the above

Q. a gas at 350 k and 15 bar has molar volume 20percent smaller than that for an ideal gas under the same condion, the z is?? which force is dominant?

Q. Two mole of ideal diatomic gas $(C_{v,m}=5/2R)$ at $300K$ and $10atm$ expanded irreversibly and adiabatically to a final pressure of $2atm$ against a constant pressure of 1 atm. Calculate change in internal energy $△U$

1. $-2164.1J$
2. $864.28J$
3. $-1052.1J$
4. $-1662.8J$

Q. The standard enthalpies of formation at 300 K for $CC{l}_4\left(l\right),H_{2}O\left(g\right),C{O}_2\left(g\right)andHCl\left(g\right)are-107,-242,-394and-93kJmo{l}^{-1},$ respectively. The value of $△U_{300}^o$ for the reaction:

$CC{l}_4\left(l\right)+2H_{2}O\left(g\right)\to C{O}_2\left(g\right)+4HCl\left(g\right)$ is
$-xkJmo{l}^{-1}$. Find the value of $x$
(Take $R=8.314J{K}^{-1}mo{l}^{-1}$)

Q. For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, $△U$ and W correspond to

1. $△U<0,W=0$
2. $△U=0,W<0$
3. $△U>0,W=0$
4. $△U=0,W>0$

Q.

A system performs $101.3J$ of work on its surrounding and absorbs $15KJ$ of heat from surroundings. The change in internal energy of the system is:

1. $15101.3J$
2. $14898.7J$
3. $13972.5J$
4. $12496.3J$

Q. Find the change in internal energy of 60 g of Argon gas when its change in temperature is 200 K.
(Given degree of freedom of argon is 3 and its molar mass = 40 g/mole)

1. $4800.3J$
2. $3741.3J$
3. $1250.4J$
4. $3500.2J$

Q. Which of the following is incorrect regarding the internal energy of the system?

1. It is a state function
2. It increases with increase in temperature
3. It can be calculated by experiment
4. It remains unaffected with change in temperature

Q. A gas occupies $2litre$ at STP. It is provided with $58.63J$ of heat so that its volume becomes $2.5litre$ at $1atm$. Calculate the change in its internal energy (in $J$).

1. 8.6
2. 10
3. 15.8
4. 11.5

Q. Two moles of an ideal monoatomic gas occupies a volume V at $27{}^{\circ }C$. The gas expands adiabatically to a volume 2V. Calculate (a) the final temperature of the gas and (b) change in its internal energy.

1. (a) 295 K (b) - 2.7 kJ
2. (a) 189 K (b) -2.7 kJ
3. (a) 295 K (b) 2.7 kJ
4. (a) 189 K (b) 2.7 kJ

Q. Two flask A and B of equal volume contain equal masses of H2 and CH4 gases at 100 K and 200 K temperature respectively. Which of the following relation is correct about total kinetic energy (E) ? (1) {(E)_{{H_2}}} = {(E)_{C{H_4}}} (2) {(E)_{{H_2}}} = 2 times {(E)_{C{H_4}}} (3) {(E)_{{H_2}}} = 4 times {(E)_{C{H_4}}} (4) 4 times {(E)_{{H_2}}} = {(E)_{C{H_4}}}

Q. When unit mass of water boils to become steam at $100C^{\circ }$ , it absorbs Q amount of heat. The densities of water and steam at $100C^{\circ }$ are $p_1$ and $p_2$ respectively and the atmospheric pressure is $p_0$. The increase in internal energy of water is

1. $Q$
2. $Q+p_0(\frac{1}{p_1}-\frac{1}{p_2})$
3. $Q+p_0(\frac{1}{p_2}-\frac{1}{p_1})$
4. $Q-p_0(\frac{1}{p_1}-\frac{1}{p_2})$

Q.

"Solids on heating emit radiations over a wide range of wavelengths".what does this statement means

Q. If the radii of the two copper sphere are in the ration $1:3$ and their temperatures are in the ratio $9:1$ then the ratio of the heat contents in them will be

1. $1:3$
2. $1:4$
3. $2:1$
4. $4:1$

Q. Two identical vessels A & B contain equal amount of ideal monoatomic gas. The piston of A is fixed but that of gas B is free. Same amount of heat is absorbed by A & B . If B's internal energy increases by 100 J the change in internal energy of A is:

1. $100J$
2. $\frac{500}{3}J$
3. $250J$
4. None of these

Q. The value of $\Delta H-\Delta U$ for the following reaction at ${37}^o$ C will be:
$2N{H}_3\left(g\right)\to N_2\left(g\right)+3H_2\left(g\right)$

1. $51.54{\text{kJ mol}}^{-1}$
2. $51.54{\text{J mol}}^{-1}$
3. $-51.54{\text{J mol}}^{-1}$
4. $5.154{\text{kJ mol}}^{-1}$

Q. The maximum efficiency of a heat engine operating between ${100}^{o}C$ and ${25}^{o}C$ is

1. 20.11%
2. 22.2%
3. 25.17%
4. None

Q. The value of $\Delta H-\Delta U$ for the following reaction at ${37}^o$ C will be:
$2N{H}_3\left(g\right)\to N_2\left(g\right)+3H_2\left(g\right)$

1. $51.54{\text{kJ mol}}^{-1}$
2. $51.54{\text{J mol}}^{-1}$
3. $-51.54{\text{J mol}}^{-1}$
4. $5.154{\text{kJ mol}}^{-1}$

Q. ∆E = 0 for which process ? 1.Cyclic process 2.Isobaric expansion process 3.Isochoric process 4.Adiabatic process.