Question

if 1 mol of an ideal gas at constant temperature changes its pressure from 5 atm to 2 atm and volume from 4L to 10 L , then enthalpy change will be option a- 20Latm b-120Latm C-0 4-100L atm

Answer 1

Answer:

the answer is zero

Explanation:

Let ...P1 =5 atm   P2=2 atm

        V1=4L       V2=10L

now, at constant temperature(isothermal)  q = -w... so U=0

H1=U + P1V1                        

H1= 20 L-atm

similarly, H2= 20 L-atm

change in enthalpy..

delta H= H2-H1

delta H= 20-20 = 0

Answer 2

Given - Original and New pressure and volume.

Find - Enthalpy change

Solution - There is no change in enthalpy.

The formula that will be used to calculate enthalpy change will be -

∆H = U + ∆PV

∆H = U + P2V2 - P1V1

Internal energy will be zero and the temperature is constant.

Keeping the values in formula to find the value of enthalpy change.

∆H = 2*10 - 5*4

∆H = 20 - 20

∆H = 0

Thus, there is no change in enthalpy. Therefore, correct answer is C-0.