Question

A sample of gas is placed into an enclosed cylinder and fitted with a movable piston. Calculate the work (in joules) done by the gas if it expands from 4.22 L to 15.61 L against a pressure of 5.63 atm.

Answer 1

Answer:

The work is -6,497.54 J

Explanation:

Work is the amount of energy transferred from one system to another by a force when a displacement occurs.

The work exchanged for a gas depends on the transformation it performs to go from the initial state to the final state.

The pressure - volume work done by a system that compresses or expands at constant pressure is given by the expression:

W= -P*ΔV

where

• W is the work exchanged by the system with the environment. Its unit of measure in the International System is the joule (J), which is equivalent to  Pa*m³
• P: Pressure. Its unit of measurement in the International System is the pascal (Pa).
• ∆V: Volume variation (∆V = Vfinal - Vinitial). Its unit of measurement in the International System is cubic meter (m³)

In this case:

• Wsystem=?
• P= 5.63 atm=570,459.8 Pa (being 1 atm=101325 Pa)
• ΔV=Vfinal - Vinitial= 15.61 L - 4.22 L= 11.39 L= 0.01139 m³ (being 1 L=0.001 m³)

Replacing:

W=  -570,459.8 Pa*0.01139 m³

Solving:

W=-6,497.54 J

The work is -6,497.54 J