Calculate the volume of 12.0 g of helium at 100°c and 1.2 atm

Volume = nRT/P

n = number of particles (moles)

R = universal gas constant (0.0821)

T = temperature (Kelvin)

P = pressure (atm)

(Assuming you have 1 mole of Helium in a chemical reaction) We would need to convert grams to moles: 12.0g He x 1 mol He/4 molar mass of He = 3 mol He

Convert Celsius to Kelvin: 100*C + 273.15 = 373.15 K

Now we can set up the equation for volume: (3mol) (0.0821) (373.15) / 1.2atm = 76.6 L of Helium gas