Question

Find the kinetic energy of 1 litre of an ideal gas at STP.

Answer 1

Given:

Universal gas constant, R = 8.314 J/(mol K)

Temperature (T) = 273 K

Molar volume of an ideal gas at STP (V_m) = 22.4 L = 22.4 × 10⁻³ m³

Number of moles in 1 litre of gas n = `(1 "L")/"V"_"m" = (1 xx 10^-3  m^3)/(22.4 xx 10^-3  m^3) = 1/22.4` moles

`"KE"_"per mole" = 3/2 RT`

`"KE"_ "per mole" = 3/2 xx 8.314 xx 273`

`"KE"_ "per mole"` = 3406.48 J/mol

`"KE"_"total" = "KE"_ "per mole" xx n`

`"KE"_"total" = 3406.48 xx 1/22.4`

KE_total = 152 J