Question

How many grams of hydrogen gas occupy 40 mL at 27°C and 710 torr?

Answer 1

Let's assume the gas behave as ideal gas so that we can apply ideal gas equation on it.

P = 710 torr = 710/760 atm = 0.934210526 atm

V = 40 mL = 0.04 L

T = 27°C = 300.15 K

R = 0.0821 L.atm/K.mol

The Ideal Gas equation is

PV = nRT

n = PV/RT

n = ( 0.934210526 atm × 0.04 L) / (0.0821 L.atm/K.mol × 300.15 K)

n = 0.0015164 mol

Now, Molar mass of H₂ gas is 2.016 g/molar ➡ this is mass for 1 mol of hydrogen gas. Then,

Required mass =

0.0015164 mol × 2.016 g/mol = 0.003057 g

Answer : 0.003057 g

** If you don't understand, comment below.