A cylinder contains 3.5 L of oxygen at 350 K and 2.5 atm . The gas is heated, causing a piston in the cylinder to move outward. The heating causes the temperature to rise to 640 K and the volume of the cylinder to increase to 9.5 L.

What is the gas pressure?

3 answers

Use the initial set of numbers and the ideal gas law to compute the number of moles, n.

n = PV/(RT)= 2.5*3.5/(0.0826*350)= 0.304 moles

I used R = 0.0826 liter*atm/(mole K)

Then use the ideal gas law again with the above value of n to solve for the unknown P.

P = nRT/V

2.51

2.511