# Calculating mass by pressure needed to move object

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1. Jan 8, 2016

### Physics123537

1. The problem statement, all variables and given/known data
A cilinder is filled with 50mg of H2 gas. In the cilinder is a piston with a surface of 27cm The temperature of the gas equals 298K. The piston rises 2cm when the temperature rises 30 degrees. Calculate the mass of the piston
Also given data:
MH2=2.02g/mol

2. Relevant equations

Ideal gas equation : p.V = n.R.T

3. The attempt at a solution
I though the volume rose with 2x27cm^2 = 54cm^3
So I used the ideal gas formula and used Volume 1 as X and Volume2 as x+54 and equaled those formulas to each other but received the wrong answer.

2. Jan 8, 2016

### TSny

Hello and welcome to PF.

You said that you "equaled those formulas to each other". Could you show the steps involved in doing this?

3. Jan 9, 2016

### Physics123537

p=nRT/V1=nRT/V2
I calculated that n= 0,024

(0,024.8,31.298K)/x=(0,024.8,31.328K)/(x+0,54)

I tried to find x there and ended up with 0,56. Then I put the x back in the formula and tried to find the pressure with it. Which was 106(pa?). How to find the mass of the piston with that is still a mystery

4. Jan 9, 2016

### haruspex

if that's the pressure, what force is it exerting on the piston?