Internal Energy

Q. Internal energy does not include

1. Rotational energy
2. Vibrational energy
3. nuclear energy
4. gravitational pull

Q.

What is the difference between internal energy and free energy?

Q. Internal energy of a system increases, when the system

1. expands
2. absorbs heat
3. does work
4. loses heat

Q. The internal energy of an ideal gas:

1. increases with increase in temperature
2. decreases with increase in temperature
3. remains unaffected with temperature
4. can be calculated by the reaction, $E=m{c}^2$

Q. A gas sample is cooled and loses 65 J of heat. The gas contracts as it cools and work done on the system equal to 20 J. What are q, w and $△U$ ?

1. $q=-65J,w=20J,△U=-45J$
2. $q=65J,w=10J,△U=-35J$
3. $q=-70J,w=10J,△U=35J$
4. $q=65J,w=20J,△U=45J$

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. 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. Internal energy is an example of

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

Q. A gas sample is cooled and loses 65 J of heat. The gas contracts as it cools and work done on the system equal to 20 J. What are q, w and $△U$ ?

1. $q=-65J,w=20J,△U=-45J$
2. $q=65J,w=10J,△U=-35J$
3. $q=-70J,w=10J,△U=35J$
4. $q=65J,w=20J,△U=45J$

Q. A system is provided with $95.2cal$ of heat and the work done by the system on the surrounding is $40J$. The internal energy

1. Increases by $600J$
2. Increases by $760J$
3. Increases by $560J$
4. None of these

Q. One mole of an ideal gas at $500K$ is expended isothermally from an initial volume of $1\text{litre}$ to $10\text{litre}$. The $\Delta E$ for this process is :

1. $163.7\text{cal}$
2. $0\text{cal}$
3. $1381.1\text{cal}$
4. $9\text{L atm}$

Q. $3000J$ of heat is given to a gas at a constant pressure of $P=(2\times {10}^{5}N/m^2)$.
If its volume increases by 10 litres during the process, find the change in the internal energy of the gas.

1. $1600J$
2. $3000J$
3. $2500J$
4. $1000J$

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 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. Internal energy of an ideal gas depends on

1. Volume
2. Temperature
3. Pressure
4. None of these

Q. The internal energy (U) of an ideal gas is plotted against volume for a cyclic process ABCDA, as shown in the figure.
The temperature of the gas at B and C are $500K$ and $300K$, respectively. The heat absorbed by the gas (in cal/mol) in this cyclic process, is :

Q. If $C_v=4.96cal/mol.K$ then the amount of heat absorbed at constant volume, when temperature of 2 moles of this gas is increased from $332K$ to $542K$ is:

1. $5208cal$
2. $2083cal$
3. $8688cal$
4. $3256cal$

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. Two moles of an ideal gas heated at constant pressure of one atmosphere from ${27}^{o}Cto{127}^{o}C.$ If $C_{v,m}=(20+{10}^{-2}T)J{K}^{-1}mo{l}^{-1},$ then $q$ and $△U$ for the process are respectively:

1. 6362.8 J, 4700 J
2. 3037.2 J, 4700 J
3. 7062.8 J, 5400 J
4. 3181.4 J, 2350 J

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 system is changed from state A to state B by one path and from B to A by another path. If $△U_1$ and $△U_2$ are the corresponding changes in internal energy, then:-

1. $△U_1+U_2=+ve$
2. $△U_1+U_2=-ve$
3. $△U_1+U_2=0$
4. None of the above

Q. One mole of an ideal gas at $500K$ is expended isothermally from an initial volume of $1\text{litre}$ to $10\text{litre}$. The $\Delta E$ for this process is :

1. $163.7\text{cal}$
2. $0\text{cal}$
3. $1381.1\text{cal}$
4. $9\text{L atm}$

Q. If the ratio of specific heat of a gas at constant pressure to that at constant volume is $\gamma ,$ the change in internal energy of a mass of gas, when the volume changes from $V$ to $3V$ under constant pressure $P$, is

1. $\frac{R}{(\gamma -1)}$
2. $PV$
3. $\frac{2PV}{\gamma -1}$
4. $\frac{\gamma PV}{\gamma -1}$

Q. Find out the internal energy change for the reaction $A\left(l\right)\to A\left(g\right)$ at $373K$. Heat of vaporisation is $40.66kJ/mol$ and $R=8.3Jmo{l}^{-1}{K}^{-1}$.

1. $50.56kJmo{l}^{-1}$
2. $22.56kJmo{l}^{-1}$
3. $37.56kJmo{l}^{-1}$
4. $45.56kJmo{l}^{-1}$

Q. Two moles of an ideal gas heated at constant pressure of one atmosphere from ${27}^{o}Cto{127}^{o}C.$ If $C_{v,m}=(20+{10}^{-2}T)J{K}^{-1}mo{l}^{-1},$ then $q$ and $△U$ for the process are respectively:

1. 6362.8 J, 4700 J
2. 3037.2 J, 4700 J
3. 7062.8 J, 5400 J
4. 3181.4 J, 2350 J