At 1 atm pressure,the heat of sublimation of gallium is 277 kJ/mol and the heat of vaporization is 271 kJ/mol.To the correct number of significant figures,how much heat is required to melt 3.50 mol of gallium at 1 atm pressure?
A) 6 kJ
B) 21 kJ
C) 256 kJ
D) 274 kJ

Question

Quizplus · Accepted Answer

The heat required to melt gallium can be calculated using Hess's Law, where the heat of sublimation equals the sum of the heat of fusion and the heat of vaporization. Rearranging this gives the heat of fusion = heat of sublimation - heat of vaporization. Substituting the given values: 277 kJ/mol - 271 kJ/mol = 6 kJ/mol. For 3.50 mol, the total heat required = 3.50 mol * 6 kJ/mol = 21 kJ.

At 1 Atm Pressure,the Heat of Sublimation of Gallium Is