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MHT CET · Chemistry · Thermodynamics (C)

Calculate the final volume when 2 moles of an ideal gas expand from \(3 \mathrm{dm}^3\) at constant external pressure 1.6 bar and the work done in the process is \(800 \mathrm{~J}\).

  1. A \(2.66 \mathrm{dm}^3\)
  2. B \(4.8 \mathrm{dm}^3\)
  3. C \(5.0 \mathrm{dm}^3\)
  4. D \(8.0 \mathrm{dm}^3\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(8.0 \mathrm{dm}^3\)

Step-by-step Solution

Detailed explanation

\(\mathrm{W}=-\mathrm{P}_{\text {ext }} \Delta \mathrm{V}=-\mathrm{P}_{\text {ext }}\left(\mathrm{V}_2-\mathrm{V}_1\right) \)
\( \mathrm{V}_1=3 \mathrm{dm}^3 \)
\( \mathrm{~V}_2=? \)
\( \mathrm{P}_{\text {ext }}=1.6 \text { bar } \)
\( \mathrm{W}=-800 \mathrm{~J}=8 \mathrm{dm}^3 \text { bar }(\because 100 \mathrm{~J}=\) \(1 \mathrm{dm}^3 \text { bar}) \)
\( -8=-1.6\left(\mathrm{~V}_2-3\right) \)
\( \mathrm{V}_2-3=5 \)
\( \mathrm{~V}_2=8 \mathrm{dm}^3\)