Question

A piston filled with 0.04 mol of ideal gas expands reversibly from 50.0mL to 375 mLat a constant temperature of `37.0^(@)C`. As it does so, it absorbs 208J of heat. The value of q and w for the process will be `:`
`( R = 8.314J // mol K , ln7.5 =2.01 )`
A. `q= + 208 J , w= + 208 J`
B. `q = + 208 J , w = - 208 J`
C. ` q = - 208 J , w= - 208 J`
D. `q = - 208 J, w= +208 J`

Answer 1

Correct Answer - b
For isothermal expansion of an ideal gas, `DeltaU = 0`. Hence,from first law of thermodynamics, `DeltaU = q+w` , we have `q= -w` . As process involves adsorption of heat, i.e., it is endothermic `q= + 208 J :. W= - 208 J`