Liquid ammonia NH3 1 boils at 33C A flask of 17 grams of liq

Liquid ammonia (NH₃ (1)) boils at -33?°C. A flask of 17 grams of liquid ammonia is heated to 293 K in two different containers. How much work is done:

a) In a sealed container?

b) In an open beaker?

Useful Information: R-0.0821 L atm K-1 mol1 8.314 J K-1 mol1 1 atm 760 torr- 1.01325 bar- 101325 Pa 0° C = 273.15 K Always assume ideal gas unless otherwise specified

Solution

17 gram of liquid ammonia = 1 mole of NH₃

Boiling point of liquid ammonia = -33^o C = 240.15 K

heated at 293 K.

gas constant R = 8.314 J K^-1 Mol^-1

a) work done for sealed container,

when an ammonia gas is heated in sealed container, there is no change in the volume delV = V₂ - V₁ = 0.

work done w = P del V

w = P x ( V₂ - V₁) = 0

no work is done in sealed container.

b) in open container

ammonia gas behaves as an ideal gas

PV = nRT

V = n RT / P

work done w = P x ( V₂ - V₁)

= P x (n R T₂ - n R T₁)  / P  

w = n R ( T₂ - T₁)

w = 1 x 8.314 x ( 293 - 240.15)

w = 439.40 J

   work done w = 439.40 J