Question

A fixed volume of a gas occupies 500 cm3 at 1270C and 152 cm of Hg. What will be its
volume at STP?

Answer 1

Given info : A fixed volume of a gas occupies 500 cm³ at 127°C and 152 cm of Hg.

To find : the volume of gas at STP.

Solution : case 1 : Here, Pressure, P₁ = 152 cm Hg = 2 atm [ as 1 atm = 76 cm Hg ]

Volume , V₁ = 500 cm³ = 500 ml

temperature, T₁ = 127°C = 400 K

Case 2 : at STP,

Pressure , P₂ = 1 atm

temperature , T₂ = 273K

now volume, V₂ = ?

Using formula, P₁V₁/T₁ = P₂V₂/T₂

⇒(2atm × 500 ml)/400K = (1atm × V₂)/273K

⇒V₂ = 682.5 ml = 682.5 cm³

therefore the volume of gas at STP is 682.5 cm³