In a system, a piston caused an expansion against an external pressure of 1.25 bar giving a change in volume of 32 L for which Δ E =-51 kJ . What was the value of heat involved:

Question

In a system, a piston caused an expansion against an external pressure of 1.25 bar giving a change in volume of 32 L for which Δ E =-51 kJ . What was the value of heat involved: (A) -55 kJ (B) -11 kJ (C) -47 kJ (D) -91 kJ

Tardigrade Admin · Accepted Answer

W =- P text ext Δ V W =-1.25 × 32=-40 lt bar =-40 × 100 J =-4000 J =-4 kJ Δ E = q + w So, q =Δ E - w =-51+4=-47 kJ

Q. In a system, a piston caused an expansion against an external pressure of 1.25 bar giving a change in volume of $32 L$ for which $Δ E = - 51 k J .$ What was the value of heat involved:

-55 kJ

-11 kJ

-47 kJ

-91 kJ

$W = - P_{ext} Δ V$

$W = - 1.25 \times 32 = - 40$ lt bar

$= - 40 \times 100 J = - 4000 J = - 4 k J$

$Δ E = q + w$

So, $q = Δ E - w = - 51 + 4 = - 47 k J$

Q. In a system, a piston caused an expansion against an external pressure of 1.25 bar giving a change in volume of 32L for which ΔE=−51kJ. What was the value of heat involved: