For the reaction, `2CO + O _(2) to 2 CO _(2) , Delta H =- 560 kJ` Two moles of CO and one mole of `O_(2)` are taken in a container of volume.1 L. They completely form two moles of `CO_(2)` the gases deviated appreciably from ideal behaviour. If the pressure in the vessel changes from 70 to 40 atm, find the magnitude of `Delta U at 500 K.(1 L atm=0.1 kJ)

Options

A. `-557 kJ`
B. `+557 kJ`
C. `-560 kJ`
D. `+ 560 kJ`

Answer

A

Explanation

From the definition of enthalpy we have `DeltaH = DeltaU + Delta (pV)= Delta U + V Deltap + pDeltaV`
As at constant volume `DeltaV = 0, so Delta U = DeltaH - V Deltap =- 560 + 1 xx 30 xx 0.1 =- 557 kJ`