Question

3. Calculate the maximum work per mole when 5 moles of an ideal gas expand isothermally and reversibly
from 20 litres to 100 litres at 27°C. [R = 8,314 * 10⁷ ergs mol-¹ deg-¹ (Ans.-200.76 * 10⁵ ergs]​

Answer 1

Answer:

Correct option is

B

−16.9 kJ

Solution:- (B) −16.9kJ

As the gas is expanded isothermally, thus work done is given by-

W=−2.303nRTlog

P

f

P

i

Given that:-

n=5 moles

R=8.314J/mol−K

T=300K

P

i

=4×10

5

Pa

P

f

=10

5

Pa

∴W=−2.303×(5×8.314×300)log

1×10

5

4×10

5

⇒W=−2.303×12470×log4(∵5×8.314×300=12470)

⇒W=−17.29kJ≈−16.9kJ

Hence the work done will be −16.9kJ.