A gas expands against a constant external pressure of 2.00 atm, increasing its volume by 3.40 L. Simultaneously, the system absorbs 400 J of heat from its surroundings. What is Δ E, in joules, for this gas?

Question

A gas expands against a constant external pressure of 2.00 atm, increasing its volume by 3.40 L. Simultaneously, the system absorbs 400 J of heat from its surroundings. What is Δ E, in joules, for this gas? (A) -689 (B) -289 (C) +400 (D) +289

Tardigrade Admin · Accepted Answer

Given, P = 2.00 atm, Δ V = 3 .4 L q = 400 J Work done by gas w = -PΔ V = - 2 × 3.4 = - 6.8 L atm = - 6.8 × 101.32 J = - 688.976 J ∴ Δ E=q+(-w) =400+(-688.976) =-288.976≈-289 J

Q. A gas expands against a constant external pressure of $2.00$ atm, increasing its volume by $3.40 L .$ Simultaneously, the system absorbs $400 J$ of heat from its surroundings. What is $Δ E$ , in joules, for this gas?

$- 689$

$- 289$

$+ 400$

$+ 289$

Given, $P = 2.00 a t m,$
$Δ V = 3.4 L$
$q = 400 J$
Work done by gas $w = - P Δ V$
$= - 2 \times 3.4$
$= - 6.8 L a t m$
$= - 6.8 \times 101.32 J$
$= - 688.976 J$
$∴ Δ E = q + (- w)$
$= 400 + (- 688.976)$
$= - 288.976 \approx - 289 J$

Q. A gas expands against a constant external pressure of 2.00 atm, increasing its volume by 3.40L. Simultaneously, the system absorbs 400J of heat from its surroundings. What is ΔE, in joules, for this gas?

−689

−289

+400

+289