Question

For silicon, Si, the heat of vaporization at its normal boiling point of 2355 °C is 297.1 kJ/mol. The entropy change when 2.26 moles of Si vapor condenses at 2355 °C, 1 atm is J/K.

Answer 1

Anst- Given - heat i, e that of vapourisation of silicon a tv = 297.1 kJ/mol is 297.1 kJ / mol Temperature , T = 2355°C - 2628k L We have osu - AHU - = 297.1 kJ mot kat 2628 = 0.1130 kJ mo K = 113 J mo 'k-1 L This is asu for I mole of Silicon . For , 2.26 moles of silicon - osv = 2,26 x 113 J milk-lx mol = 255.28 J mol-'k 'x mo - 255.385kl The entropy change is 255.387|K.