Question

At 27°C one mole of an ideal gas is compressed isothermally and reversibly from a pressure of 2 atm to 10 atm. The values of ∆E and q are (R = 2)

• A. 0, –965.84 cal
• B. – 965.84 cal, + 965.84 cal
• C.
  • 865.58 cal, –865.58 cal
• D. –865.58 cal, –865.58 cal

Answer 1

Answer: (A)

0, –965.84 cal

Answer 2

$w = - 2.303nRT\log\frac{P_{1}}{P_{2}}$

$\mathbf{= 2.303}\mathbf{\times}\mathbf{1}\mathbf{\times}\mathbf{2}\mathbf{\times}\mathbf{300}\mathbf{\log}\frac{\mathbf{2}}{\mathbf{10}}\mathbf{= 965.84}$

At constant temperature $\Delta E = 0$

$\Delta E = q + w$; $q = - w = - 965.84cal$