Ideal gas law problem

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1. Jan 5, 2015

TaraaaK

does anyone know how to do this question. it feels like theres a part of the question missing as i dont know how to complete the equation

The pressure of a fixed mass of gas in a sealed sphere is measured to be 1.02 x 10^5 Pa at a temperature of 253K. Assuming the volume of the sphere doesnt change calculate the pressure within the sphere if the temperature is increased to 281K
(universal gas constant R =8314 J/K/mol

because it's a fixed mass of gas do i ignore n? when doing the equation

2. Relevant equations
PV=nRT

3. The attempt at a solution
(1.02 x 10^5) V = n (8314)(253)
1.02 x 10^5 V = 2103442n

2. Jan 5, 2015

Bystander

What equation are you trying to complete?

3. Jan 5, 2015

TaraaaK

the first part first of all,but there are two unknown variables so i'm not sure what to do

4. Jan 5, 2015

TaraaaK

i know i need to find the volume of the sphere for the first part but iam unsure of how to get a number for n

5. Jan 5, 2015

Bystander

How are you going to use the volume of the sphere once you get it?

6. Jan 5, 2015

TaraaaK

when i have the volume i will use it to find the pressure like so

P = (n(8314)(281)) / V

7. Jan 5, 2015

Bystander

So, what all has changed besides temperature and pressure?

8. Jan 5, 2015

nothing

9. Jan 5, 2015

Bystander

Correct.
Just because the equation uses two variables, does not mean you have to find values for both if they're both constant, and you're interested in solving for the value of some other variable.

10. Jan 5, 2015

TaraaaK

Thank you so much
:)