Question

Room temperature is often assumed to be 25∘c. Calculate the molar volume of an ideal gas at 25∘c and 1 atm pressure.

Answer 1

Answer:

• 24.5 liter / mol

Explanation:

1) Data:

a) T = 25°C = 25 + 273.15K = 298.15 K

b) P = 1 atm

c) assumption: ideal gas

2) Formulae and principles

a) Ideal gas equation: p V = n R T, where:

• p = pressure
• V = volume
• n = number of moles
• R = universal constant of gases = 0.0821 atm-liter / K-mol
• T = absolute temperature (Kelvin)

b) Molar volume: ν = V / n, where:

• ν = molar volume
• V = volume
• n = number of moles

3)  Solution:

• p V = n R T⇒ V/n = ν = RT / p =

                                            = 0.0821 atm-liter / mol-K × 298.15 K / 1 atm

                                            = 24.5 liter / mol