Question

A system undergoes a change such that the pressure changes from 0.36 atm to 0.34 atm and the volume changes from 8 L to 19 L. Simultaneously. Δυ-358 J. What is ΔΗ in Joules?

Answer 1

Answer : The value of
`\Delta H` is 4.76 J

Explanation :

Formula used :

`\Delta H=\Delta U+\Delta n_g* RT`

According to the ideal gas equation,

`PV=nRT\\\\\Delta(PV)=\Delta n_gRT`

So,

`\Delta H=\Delta U+\Delta (PV)`

`\Delta H=\Delta U+(P_2V_2-P_1V_1)`

where,

`\Delta U` = internal energy of the reaction = -358 J

`\Delta H` = enthalpy of the reaction = ?

`P_1` = initial pressure = 0.36 atm

`P_2` = final pressure = 0.34 atm

`V_1` = initial volume = 8 L

`V_2` = final volume = 19 L

Now put all the given values in the above formula, we get:

`\Delta H=\Delta U+(P_2V_2-P_1V_1)`

`\Delta H=(-358J)+(0.34* 19-0.36* 8)L.atm`

`\Delta H=(-358J)+3.58L.atm`

conversion used :
`1L.atm=101.33J`

`\Delta H=(-358J)+3.58* 101.33J`

`\Delta H=4.76J`

Therefore, the value of
`\Delta H` is 4.76 J