00:02
Hi there, in this question we have a sample of gas, so therefore its number of moles are going to be constant, and we are not told this, but in order to work this problem, temperature must also be constant.
00:16
We're not told anything about temperature, but if the temperature is changing, we would not be able to answer this problem.
00:23
So we have to assume that the temperature is also constant as the pressure and volume change.
00:29
So this relationship is described by boyle's law.
00:34
Boyle's law is a gas law that says when the number of moles in temperature are constant, pressure and volume of the gas sample are indirectly proportional, or inversely proportional if you prefer.
00:52
What that means is as one goes up, the other goes down and vice versa, and they do so proportionately.
01:00
The equation then for boyle's law is p1 times v1 equals p2 times v2.
01:09
This shows that indirect relationship.
01:14
So p is pressure, v is volume, the ones represent the initial conditions, and the twos represent the new conditions.
01:20
So we are starting out with a gas that has an initial volume of 2 .8 liters at a pressure of 755 millimeters of mercury.
01:36
So that volume again was 2 .8 liters...