# How do I find the final volume of this question using both Boyle's law and Charles' law?

Methane gas can be condensed by cooling and increasing the pressure. A 600L sample of methane gas at 25 degrees celsius and 100 kPa is cooled to -20 degrees celsius. In a second step, the gas is compressed until the pressure is quadrupled. What will be the final volume be?

### 3 Answers

- Anonymous1 decade agoFavorite Answer
P1 x V1/T1=P2 x V2/T2

V1=600L

T1=25 C = 298.15 K

P1=100 kPa

P2= 4 x (P1) = 400 kPa

T2= -20 C = 253.15 K

V2= ?

ANS:

(600 * 100) / 298.15 = 201.240986

201.240986 = 400V/253.15

V=127.36 L

- Anonymous1 decade ago
You want to use the Combined Gas Law. The formula is:

P1 x V1 divided by T1 = P2 x V2 divided by T2. Now set up the formula to solve for your unknown:

V2 = P1 x V1 x T2 divided by T1 x P2. Now list your values:

P1 = 100 kPa (101.3 kPa - 1 atm. Divide 100 by 101.3

= .99 atm

V1 = 600 L

T1 = 25 C + 273K = 298 Kelvin

P2 = .99 x 4 = 3.96 atm

V2 = unknown

T2 = -20 C + 273 K = 293 K Now plug your values into the

formula

V2 = .99 atm x 600 L x 293 K divided by 298 K x 3.96 atm

The atm and K cancel each other out. You are left with:

.99 x 600 L x 293 divided by 298 x 3.96 = 114042 divided by 1180.08 =147.48 L

- 1 decade ago
Volume of a gas is porportional to temperature and inversley porportional to pressure. 25 celcius is 198K and -20 is 153K since zero kelvin is absolute zero where all molecules stop moving and zero celcius is 173K. Kelvin is always the temperature scale used in science except in a few cases.

in the first part, the volume will decrease by the same factor that temperature decreases and the new volume is 600L*(153K/198K)

in the second part, volume decreases by the same factor that pressure increases, so divide the above volume by 4., right now, the easiest way to divide by 4 is 600/4=150

V=150L(153/198)=115.9.

116L