# Heat and Work

## Trending Questions

**Q.**In the cyclic process shown in P-V diagram, the magnitude of the work done is

- π(P2−P12)2
- π(V2−V12)2
- π4(P2−P1)(V2−V1)
- π(V2−V1)2

**Q.**Which of the following statements is incorrect?

- For an isothermal process, dT = 0.

Where, T is the temperature of the system. - For an isobaric process, dP = 0.

Where. P is the pressure of the system. - For an Isochoric process, dV = 0.

Where, V is the volume of the system. - For an adiabatic process, dW = 0,

where, W is the work done in the process

**Q.**6 g of O2 gas at STP is expanded against atmosphere so that the volume is doubled. Thus, the work done is:

- 22.4 L atm
- - 4.2 L atm
- 5.6 L atm
- 11.2 L atm

**Q.**Identify the pair of intensive properties among the following.

- Enthalpy and temperature
- Volume and temperature
- Enthalpy and volume
- Temperature and refractive index

**Q.**An ideal monatomic gas is taken round the cycle ABCD as shown in the figure. The work done during the cycle is:

- 2pV
- zero
- pV
- 12pV

**Q.**A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5J and 8J, respectively. Now gas is brought back at A by another process during which 3J of heat is evolved. In this reverse process of B to A:

- 10 J of the work will be done by the gas.
- 6 J of the work will be done by the gas.
- 10 J of the work will be done by the surrounding on gas.
- 6 J of the work will be done by the surrounding on gas

**Q.**Calculate the total work done along the path 'ABCD' (as shown in figure) for a one mole of monoatomic gas.

- W= P0V0(1+ln 2)
- W=−RT ln 2
- W=−P0V0(1+ln 2)
- W=−P0V0 ln 2

**Q.**A heating coil is immersed in a 100 g sample of H2O(l) at 1 atm and 100∘C in a closed vessel. In this heating process, 60% of the liquid is converted in to gaseous form at constant pressure of 1 bar. Densities of liquid and gaseous water under these condition are 1000kg/m3, 0.60kg/m3 respectively. magnitude of the work done for the process is :

- None of these
- 4997 J
- 3970 J
- 9994 J

**Q.**Which of the following are extensive properties?

- Volume and enthalpy
- Volume and temperature
- Volume and specific heat
- Pressure and temperature

**Q.**One mole of an ideal gas (Cv=20 JK−1mol−1) initially at STP is heated at constant volume to twice the initial temperature. For the process, work done (w) and q will be :

- w=0; q=5.46 kJ
- w=0; q=0
- w=−5.46 kJ; q=5.46 kJ
- w=5.46 kJ; q=5.46 kJ

**Q.**

For the process to occur under adiabatic conditions, the correct condition is:

(i) Δ T=0

(ii) Δ p=0

(iii) q = 0

(iv) w = 0

**Q.**16 g oxygen gas expands at STP to occupy double of its original volume. The work done during the process is

- -260.2 cal
- 260.2 kcal
- -272.8 cal
- 272.8 kcal

**Q.**56 g of iron reacts with dilute H2SO4 at 30 oC. Work done (in cal) in:

(I) a closed vessel of fixed volume

(II) an open vessel

is:

(given molar mass of Fe is 56 g/mol)

- I II0−606
- I II0 0
- I II−600 600
- I II0−303

**Q.**1 mole of an ideal gas, initially at 400 K and 10 atm is first expanded at constant pressure till the volume is doubled. Then the gas is made to undergo an isochoric process, in which its temperature is found to decrease. In the last step, the gas was compressed reversibly and adiabatically to its initial state. Determine the net work involved in this cyclic process (in terms of R). Given, CV for gas =1.5 R, (4)−1/3=0.63. If |W|=2 R×z, what is the value of z?

**Q.**16 g oxygen gas expands at STP to occupy double of its original volume. Calculate the work done during the process is:

- 260 kcal
- 180 kcal
- 130 kcal
- −272.8 kcal

**Q.**Assign the sign of work done (based on SI convention) in the following chemical changes taking place against the external atmospheric pressure:

(I) N2(g)+3H2(g)→2NH3(g)

(II) NH4HS(s)→NH3(g)+H2S(g)

(III) C(s)+CO2(g)→2CO(g)

(IV) C2H6(g)+3.5O2(g)→2CO2(g)+3H2O(l)

- I II III IV

+ − − + - I II III IV

+ + − − - I II III IV

− + 0 + - I II III IV

+ − 0 −

**Q.**During an adiabatic reversible change, the density becomes 116th of the initial value. Then find P1P2 is : (γ=1.5)

- 16
- 4
- 32
- 64

**Q.**Closed systems can exchange which of the following with the surroundings?

- Heat
- Matter
- Heat and Matter
- Neither heat nor matter

**Q.**In the figure , the net amount of work done will be:

- Positive
- Negative
- Zero
- Infinity

**Q.**Which of the following represents the correct relation between Ksp(AgCl) and standard reduction potential of Ag|AgCl( saturated ) in KCl electrode?

- E0Cl−/AgCl/Ag=RTF ln Ksp
- E0Cl−/AgCl/Ag=RTF ln Ksp−E0Ag+/Ag
- E0Cl−/AgCl/Ag=RTF ln Ksp+E0Ag+/Ag
- E0Cl−/AgCl/Ag=E0Ag+/Ag

**Q.**56 g of iron reacts with dilute H2SO4 at 30 oC. Work done (in cal) in:

(I) a closed vessel of fixed volume

(II) an open vessel

is:

(given molar mass of Fe is 56 g/mol)

- I II0−606
- I II0 0
- I II−600 600
- I II0−303

**Q.**Calculate the total work done along the path 'ABCD' (as shown in figure) for a one mole of monoatomic gas.

- W=−RT ln 2
- W=−P0V0(1+ln 2)
- W= P0V0(1+ln 2)
- W=−P0V0 ln 2

**Q.**One mole of an ideal gas (Cv=20 JK−1mol−1) initially at STP is heated at constant volume to twice the initial temperature. For the process, work done (w) and q will be :

- w=0; q=5.46 kJ
- w=0; q=0
- w=−5.46 kJ; q=5.46 kJ
- w=5.46 kJ; q=5.46 kJ

**Q.**

For the reaction C2H4(g)+3O2(g)→2CO2(g)+2H2O(l), the difference between enthalpy change and internal energy change is:

- −RT
- +RT
- −2RT
- +2RT

**Q.**A heating coil is immersed in a 100 g sample of H2O(l) at 1 atm and 100∘C in a closed vessel. In this heating process, 60% of the liquid is converted in to gaseous form at constant pressure of 1 bar. Densities of liquid and gaseous water under these condition are 1000kg/m3, 0.60kg/m3 respectively. magnitude of the work done for the process is :

- 4997 J
- 3970 J
- 9994 J
- None of these

**Q.**

An ideal gas is taken around the cycle ABCA as shown in P-V diagram.

The net work done by the gas during the cycle is equal to:

- 6P1V1
- 12P1V1
- 5P1V1
- P1V1

**Q.**

- w1<w2<w3<w4
- w3=w2=w1=w4
- w3<w2<w4<w1
- w3>w1>w2>w4

**Q.**One mole of an ideal gas (Cv=20 JK−1mol−1) initially at STP is heated at constant volume to twice the initial temperature. For the process, work done (w) and q will be :

- w=0; q=5.46 kJ
- w=0; q=0
- w=−5.46 kJ; q=5.46 kJ
- w=5.46 kJ; q=5.46 kJ

**Q.**One mole each of CaC2, Al4C3 and Mg2C3 react with H2O in separate open flasks at 25oC. Numerical value of the work done by the system is in the order:

Given reactions:

CaC2(s)+2H2O(l)→Ca(OH)2(s)+C2H2(g)

Al4C3(s)+12H2O(l)→4Al(OH)3(s)+3CH4(g)

Mg2C3(s)+4H2O(l)→2Mg(OH)2(s)+CH3−C≡CH(g)

- CaC2<Al4C3<Mg2C3
- CaC2=Mg2C3<Al4C3
- CaC2<Mg2C3<Al4C3
- CaC2>Al4C3>Mg2C3

**Q.**Closed systems can exchange which of the following with the surroundings?

- Heat
- Matter
- Heat and Matter
- Neither heat nor matter