Question

A balloon is filled to a volume of 5.10l at a temperature of 27.1ºc. if the pressure in the balloon is measured to be 2.20 atm, how many moles of gas are contained inside the balloon?

Answer 1

We can find the number of moles in the balloon using the ideal gas law equation 
PV = nrT 
where 
P - pressure - 2.20 atm 
V - volume - 5.10 L
n - number of moles 
r - universal gas constant - 0.08206 LatmK⁻¹mol⁻¹
T - temperature in Kelvin - 27.1 °C + 273 = 300.1 K
substituting the values in the equation 
2.20 atm x 5.10 L = n x 0.08206 LatmK⁻¹mol⁻¹ x 300.1 K
n = 0.456 mol
number of moles of gas is 0.456 mol