Question

A balloon containing 0.143 mol Ne gas has a volume of 1.6 L at 2.2 atm and 28°C. How many grams of neon should be added to the balloon to increase the volume to 2.9 L at the same pressure and temperature?

Answer 1

PV = nRT

where:

P is the pressure of the gas = 2.2 atm

V is the volume of the gas = 2.9

n is the amount of substance of gas (in moles) = ?

R is gas constant = = 0.0821 L atm K-1 Mol-1

T is the absolute temperature of the gas = 28 +273 = 301 K

substitute in the equation and calculate moles

n = 2.2 x 2.9 / 0.0821 x 301 = 0.258 Moles

Totally 0.258 Moles of Ne is needed.

Already we have 0.143 moles of Ne

Moles of Ne is to be added = 0.258 -0.143 = 0.115 Moles

Atomic mass: 20.18

Weight of Ne = 0.115 x 20.18 = 2.321 gm

Hence 2.321 gm of Ne is to be added further