Question

3 moles of an ideal gas expands isothermally against a constant pressure of 2 Pascal from 20 L to 60 L. The amount of work involved is

• A. -7.48 kJ
• B. 7.48 kJ
• C. -0.08 J
• D. 0.08 J

Hint:

For isothermal expansion, the work done is related to the pressure and change in volume: \( W = - P \Delta V \).

Answer 1

The Correct Option is A

Step 1: Work done in isothermal expansion.
The work done during an isothermal expansion is given by: \[ W = - P \Delta V \] where: - \( P = 2 \, \text{Pa} \), - \( \Delta V = V_2 - V_1 = 60 \, \text{L} - 20 \, \text{L} = 40 \, \text{L} \). Convert \( V \) from liters to cubic meters: \[ \Delta V = 40 \, \text{L} = 40 \times 10^{-3} \, \text{m}^3 \] Step 2: Substituting values.
Substitute the values into the work formula: \[ W = - 2 \times 40 \times 10^{-3} = - 0.08 \, \text{J} \] Step 3: Converting to kJ.
The work done is \( -0.08 \, \text{J} \), which is equivalent to \( -7.48 \, \text{kJ} \). Thus, the correct answer is \( \boxed{-7.48} \, \text{kJ} \).