Calculate the number of mol of helium in a 2.21-L balloon at 25C and 2.64 atm of pressure

Answer 1

Use the ideal gas law. PV = nRT

Rearrange to solve for n.

n = PV / RT

P = 2.64 atm

V = 2.21 L

T = 25 °C → convert to Kelvin = 25 + 273 = 298 K

R = 0.0821 L atm mol^-1 K^-1

n = (2.64 x 2.21) / (0.0821 x 298) = 0.238 mol