Question

Calculate maximum work done when 32 g of oxygen expanded isothermally and reversibly from pressure 2 bar to 1 bar at 298 K.

Answer 1

Given: Mass of oxygen (m) = 32 g

Initial pressure (P₁) = 2 bar

Final pressure (P₂) = 1 bar

Temperature (T) = 298 K

Universal gas constant (R) = 8.314 J mol⁻¹ K⁻¹

The molar mass of oxygen (O₂) = 32 g/mol

n = `"Mass"/"Molar mass"`

= 32/32`

= 1 mole

W = `-2.303 nRT log_10  P_1/P_2`

= `-2.303 xx 1 xx 8.314 xx 298 xx log_10  2/1`

= − 2.303 × 8.314 × 298 × 0.3010

= −1717.5 J