Question

What is the change in internal energy when a gas constants from 377 ml to 177 ml under a constant
pressure of 1520 torr , while at the same time being cooled by removing 124 J heat ?
[Take :(1 L atm )n= 100 J]
A. `-24 J`
B. ` -84 J`
C. `-164 J`
D. `-248 J`

Answer 1

Correct Answer - B
`C_(4)H_(4)+HCl to C_(2) H_(5)Cl`
`Deltan_(g) = - 1`
HCl is limiting reagent `rArr DeltaU= DeltaH - Deltan_(g)RT`
` = - 185 +(1 xx 8.314 xx 10 ^(-3) xx 300) = - 69.8 kJ`
For two mole of HCl `= - 69.8 xx2 = - 139.6 kJ`