
Kristy L. answered 07/26/21
Undergraduate Math Tutor for 2024-2025 School Year
An ideal gas is allowed to expand from 7.20 L to 46.8 L at constant temperature. By what factor does the volume increase?
In order to calculate the factor in which the volume increases, we must divide the two numbers.
46.8 L / 7.20 L = 6.5
Factor: 6.5
The pressure will
- decrease by that same factor.
- increase by that same factor.
The pressure decreases by that same factor (6.5) because pressure and volume are inversely proportional to each other. This means that as pressure increases, volume decreases and when pressure decreases, volume increase. Basically, they increase and decrease in opposite directions of each other. We know that the pressure and volume are inversely proportional to each other because of a derivation of the ideal gas law: Boyle's Law.
P1V1 = P2V2
Since, we can see that they are on the same side of the ideal gas law: PV = nRT, they are inversely proportional to each other. However, if they were on opposite sides (ex. V and n), they would be directly proportional to each other.
If the initial pressure was 109 atm, what is the final pressure?
Using Boyle's Law, we can calculate the final pressure:
P1V1 = P2V2
P1 = first pressure
P2 = second pressure
V1 = first volume
V2 = second volume
P1 = 109 atm
P2 = ?
V1 = 7.20 L
V2 = 46.8 L
Plugging those numbers in:
P1V1 = P2V2
(109 atm)(7.20 L) = P2 (46.8 L) Solve using algebra
P2 = 16.8 atm (3 significant figures)
Pfina l = 16.8 atm