# Work Done in Isothermal Reversible Process

## Trending Questions

**Q.**One mole of an ideal gas at 300 K is expanded isothermally from an initial volume of 1 litre to 10 litres. The value of △U for this process is:

(R=2 cal mol−1K−l)

- 163.7 cal
- zero
- 138.1 cal
- 9 atm L

**Q.**The reversible expansion of an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?

- T1=T2
- T3>T1
- Wisothermal>Wadiabatic
- ΔUisothemal>ΔUadibatic

**Q.**How much work in kJ mol−1 unit is done by reversible and isothermal expansion of 1.2 mole of an ideal gas to 10 times of its original volume at 27oC ?

- 4.191
- 6.892
- −6.892
- −4.191

**Q.**The molar heat capacity of water at constant pressure, Cp, m is 75 JK−1mol−1. when 1.0 kJ of heat is supplied to 100 g of water which is free to expand, increase in the temperature of water is:

- 4.8 K
- 6.6 K
- 1.2 K
- 2.4 K

**Q.**Calculate q, w, ΔU for the isothermal reversible expansion of 1 mole of an ideal gas from an initial pressure of 1.0 bar to a final pressure of 0.1 bar at a constant temperature of 273 K.

- q=−w=5.22 kJ and ΔU=0
- q=−w=6.22 kJ and ΔU=0
- w=q=5.22 kJ and ΔU=0
- w=q=ΔU=0

**Q.**The work done in erg for the reversible expansion of 1 mole of an ideal gas from a volume of 10 litres to 20 litres at 25oC is

- 2.303×298×0.082 log 2
- −298×107×8.314×2.303 log 2
- −2.303×298×0.082 log 0.5
- 2.303×298×2 log 2

**Q.**The work done by 100 calorie of heat in isothermal expansion of ideal gas is:

- −418.4 J
- 41.84 J
- −4.184 J
- None of these

**Q.**Find the work done when 2 moles of hydrogen expands isothermally from 15 L to 50 L against a constant pressure of 1 atm at 250C.

- 820.8 cal
- −848.2 cal
- 84.7 cal
- −848.2 kcal

**Q.**Calculate the work done when 2 moles of hydrogen expand isothermally and reversibly at 25 ∘C from 15 to 45 litres.

- −1309 calories
- −14.36 calories
- −2872 calories
- −28.72 calories

**Q.**Find the work done (in kJ) when one mole of the gas is expanded reversibly and isothermally from 5atm to 1 atm at 25oC

- −10 kJ
- −2 kJ
- −8 kJ
- −4 kJ

**Q.**

A balloon filled with helium ($32\xb0\mathrm{C}$ and $1.7\mathrm{atm}$) bursts. Immediately afterwards the expansion of helium can be considered as:

reversible isothermal

Irreversible isothermal

reversible adiabatic

irreversible adiabatic

**Q.**If a certain mass of gas is made to undergo separately adiabatic and isothermal expansion to the same pressure, starting from the same initial condition of temperature and pressure, then, as compared to that of isothermal expansion, in the case of adiabatic expansion, the final

- volume and temperature will be higher
- volume will be lower but the final volume will be higher
- volume and temperature will be lower
- temperature will be lower but the final volume will be higher

**Q.**

$1$ mol of an ideal gas expands reversibly and isothermally from $1\mathrm{l}$ to $100\mathrm{l}$ at $300\mathrm{K}$. The heat exchange during the process is near?

**Q.**Which one of the following is correct for the isothermal expansion of an ideal gas?

- U increases but H decreases
- U and H are unchanged
- H increases but U decreases
- U and H increases

**Q.**5 moles of an ideal gas at 27∘C expands isothermally and reversibly from a volume of 6 L to 60 L. The work done in kJ is:

- 14.28 kJ
- 20.32 kJ
- -28.72 kJ
- -32.60 kJ

**Q.**

5.6 litre of helium gas at STP is adiabatically compressed to 0.7 litre. Taking the initial temperature to be T1, the work done on the gas is:

- 98RT1
- 98RT1
- 32RT1
- 158RT1

**Q.**1 mole of CO2 gas at 300 K is expanded under reversible adiabatic condition such that its volume becomes 27 times the initial volume. Calculate the work done by the gas.

(Given γ=1.33 and CV=25.08 Jmol−1K−1 For CO2)

**Q.**The work done by 200 calorie of heat in isothermal expansion of ideal gas is:

- −836.8 J
- −418.4 J
- −555.2 J
- 664.5 J

**Q.**The combination of plots which does not represent isothermal expansion of an ideal gas is:

- B and D
- A and D
- B and C
- A and C

**Q.**A given mass of gas expands reversibly from state A to state B by three paths 1, 2 and 3 as shown in the figure. If w1, w2, and w3 respectively are the work done by the gas along three paths, then:

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

**Q.**

For an ideal gas, the work of reversible expansion under isothermal condition can be calculated by using the expression W=−nRT lnVfVi. A sample containing 1.0 mol of an ideal gas is expanded isothermally and reversible to ten times of its original volume, in two separate experiments. The expansion is carried out at 300 K and at 600 K respectively. Choose the correct option.

(a) Work done at 600 K is 20 times the work done at 300 K

(b) Work done at 300 K is twice the work done at 600 K

(c) Work done at 600 K is twice the work done at 300 K

(d) ΔU = 0 in both cases

**Q.**Carbon monoxide is allowed to expand isothermally and reversibly from 10 m3 to 20 m3 at 300 K and work obtained is 4.754 kJ. Calculate the number of moles of carbon monoxide

- 27.5 mol
- 5.5 mol
- 2.75 mol
- 55.0 mol

**Q.**The total internal energy change for a reversible isothermal cycles is

- Always negative
- Always 100 calories per degree
- 0
- Always positive

**Q.**

A rigid diatomic ideal gas undergoes an adiabatic process at room temperature. The relation between temperature and volume of this process is ${\mathrm{TV}}^{\mathrm{x}}=$constant, then $\mathrm{x}$ is:

$\frac{5}{3}$

$\frac{2}{5}$

$\frac{2}{3}$

$\frac{3}{5}$

**Q.**An ideal gas is allowed to expand against a constant pressure of 2 bar from 10 L to 50 L in one step. Calculate the magnitude of work done by the gas. If the same expansion were carried out reversibly, will the magnitude work done be higher or lower than the earlier case? (Given that, 1 L bar=100 J)

- −8 kJ, lower
- 8 kJ, lower
- 8 kJ, higher
- −8 kJ , higher

**Q.**Consider an ideal gas that occupies 2.50 dm3 at a pressure of 3 bar. If the gas is compressed isothermally at a constant pressure Pext, so that the final volume becomes 0.5 dm3. Calculate the value of Pext and the work done respectively.

Given: 1 bar.L = 100 J

- 20 bar and 1000 J
- 15 bar and 3000 J
- 30 bar and 1500 J
- 10 bar and 3750 J

**Q.**The graph given below shows the total work done in an expansion when the state of an ideal gas is changed reversibly and isothermally from (Pi, Vi) to (Pf, Vf). Compare the work done in the above case with that carried out against a constant external pressure Pf.

(i) Area ABVfVi represents total work done for a reversible isothermal expansion from (Pi, Vi) to (Pf, Vf).

(ii) Area CBVfVi represents work done against a constant pressure Pf.

- work (i) = work (ii)
- work (i) > work (ii)
- work (i) < work (ii)
- Cannot be defined

**Q.**

What is reversible isothermal expansion? Give an example.

**Q.**

5 moles of an ideal gas expand isothermally and reversibly from a pressure of 10 atm to 2 atm at 300k. What is the largest mass which can be lifted through a height of 1 meter in this expansion?

- 2041 kg
- 2049 kg
- 2409 kg
- 4129 kg

**Q.**Calculate the maximum work done (in cal) when the pressure on 10 grams of hydrogen is reduced from 20 to 1 atm at a constant temperature of 273 K if the gas behaves ideally.

- +8180 cal
- −8810 cal
- −8180 cal
- +8810 cal