Question

478 J of work must be done to compress a gas to half its initial volume at constant temperature. How much work must be done to compress the gas by a factor of 12.0, starting from its initial volume?

I was thinking of using PV = W formula. Like

478 = P(V/2)
956 = PV

W = P(V/12)
12W/V = P
956 = (12W/V)(V)
956 = 12W
W = 79.66667 J

is this correct? could someone please help?

Answer 1

Step-by-step explanation:

I don't think so. Think about it. To compress the volume by a factor of 2 it takes 956 Joules.

Now you come along and you want to get the pressure for 1/12 of the volume. It's going to take a huge pressure to do that.

I would suggest that you have to use a modified form of the formula.

PV = 956

You need to compress the volume by 1/6

P(V/6) = 956

6 * PV/6 = 6 * 956

PV = 5736 J

Why did I only take 1/6? Because. 956 represents the pressure needed for 1/2 the volume. You need to multiply 1/2 * 1/6 to get 1/12