1. Feb 26, 2012

### SAFiiNA

1. The problem statement, all variables and given/known data
A fixed mass of gas at a constant pressure of 1 x 105 N/m2 (pascal) expands to twice its volume at constant temperature of 27°C. The volume is then kept constant, and the gas is heated to 87°C. Calculate the final gas pressure.

2. Relevant equations
I think this is the equation PV/nT=R that I need for this question.

3. The attempt at a solution
I am clueless to be honest. I am only given pressure and temperature to work this out. Can anyone please help me?

2. Feb 26, 2012

### Staff: Mentor

Well the system is closed to the number of atoms (or moles) is fixed. Given three variables P, V, T, if one is fixed, then there is a linear relationship between the other two. For example if T is fixed (constant), then by the ideal gas law, PV = some constant. So if V doubles, what happen to P?

3. Feb 26, 2012

### th4450

Then, volume is constant, apply pressure law.
$\frac{p_{1}}{T_{1}}$ = $\frac{p_{2}}{T_{2}}$
*Remember to change the temperature from oC to K

Last edited: Feb 26, 2012
4. Feb 26, 2012

### SAFiiNA

Thank you guys for your help. I worked it out and I have got the answer 12 x 104..is this correct?

5. Feb 26, 2012

### Staff: Mentor

It would help if one were to show the steps (equations) and provide units with the numbers.

6. Feb 26, 2012

### SAFiiNA

I worked it out using the formula mentioned above on this thread. So P1 = 1x105 N/m2, T1 = 27°C + 273 = 300K, P2 = ? & T2 = 87°C + 273 = 360K.

1 x 105N/m2 / 300 = P2 / 360
1x105 x 360 = P2 x 300
1x105 x 360 / 300 = P2
P2 = 12 x 104 N/m2

7. Feb 26, 2012

### th4450

p1 is not correct because "a constant pressure of 1 x 105 N/m2 (pascal) expands to twice its volume at constant temperature of 27°C"

8. Feb 27, 2012

### SAFiiNA

th4450 thank you so much for your help. I have done it right now and got it checked by my teacher. Thanks :)