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 deltae in joules, for this gas? Options

Answer 1

Answer:  - 288.8 J

Explanation: According to first law of thermodynamics:

$\Delta E=q+w$

$\Delta E$=Change in internal energy  

q = heat absorbed or released

w = work done or by the system

w = work done by the system=$-P\Delta V$  {Work is done by the system as the final volume is greater than initial volume and is negative}

w = =$-2.0atm\times 3.40L= - 6.8Latm=-688.8Joules$  {1Latm=101.3J}

q = +400J   {Heat absorbed by the system is positive}

$\Delta E==400-688.8= -288.8J$