Question

A sample of nitrogen gas expands in volume from 1.4 to 6.2 L at constant temperature. Calculate the work done in joules if the gas expands (a) against a vacuum: (b) against a constant pressure of 0.64 atm: 10 Enter your answer in scientific notation. (c) against a constant pressure of 4.3 atm: Enter your answer in scientific notation.

Answer 1

To calculate the work in expansion use the formula w= -PdV

Here P= pressure

dV = volume change

volume change = 6.2 L-1.4 L

= 4.8 L
a) in vacuum P = 0 then
w= - 0 atm * 4.8 L

= 0 L*atm = 0 J

b) at 0.64 atm;

w= - 0.64atm * 4.8L

= -3.072 L*atm

- 3.072 L*atm (101.3J/L*atm)

= -311.19 J
= - 3.119*10^2 J

c) at 4.3 atm;

w= - 4.3 atm * 4.8L

= -20.64 L*atm

- 20.64 L*atm (101.3J/L*atm)

= -2090.832 J

= -2.09*10^3 J