A ballon is filled with 30.0g of helium gas. What volume can be filled to a pressure of 1.15 atm if the temperature is 20.0°C?

156.7mL

Explanation:

First we need to find the number of mole of He. This can be achieved by doing the following:

Mass of He from the question = 30g

Molar Mass of He = 4g/mol

Number of mole = Mass /Molar Mass

Number of mole of He = 30/4

Number of mole of He = 7.5moles

Now, we can obtain the volume as follows:

P = 1.15 atm

T = 20°C = 20 + 273 = 293K

R = 0.082atm.L/Kmol

n = 7.5moles

V =?

Recall: PV = nRT

V = nRT/P

V = (7.5 x 0.082 x 293)/1.15

V = 156.7mL

Therefore, the volume that can be filled to that pressure is 156.7mL