Answer to Question #176363 in General Chemistry for Earl

Question

Solve this problem aboutmolar heat of vaporizationn to identifu heat involve.

a)what is the heat (q) needed by water with molar heat of vaporization of 40.7kJ if it is 50.0g in mass and boils at 100°C? Note that the molar mass is 18.0g/mol

b)How will you compare it with the heat needed by alcohol with molar heat of vaporization 44.0kJ at 35.0g and boils at 82.5°C?Note that the molar mass of isopropyl alcohol is 60.1 g/mol.

Answer 1

Let molar heat of vaporization be ∆H_vap

∆H_vap = 40.7 kJ

Moles of $H2O = \frac{50}{18}=2.78 moles$

Heat = $40.7 × 2.78=113.146 kJ$