Answer
Atmosphere (atm) is a unit of pressure, hence it describes the pressure of the gas.
Work Step by Step
3 atm means the gas is exerting the pressure of 3 atmosphere
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.