Calculate the number of kJ of heat necessary to raise the temperature of 60.0 g of aluminium from 35°C to 55°C. Molar heat capacity of Al is 24 J mol–1 K–1.


We Know that,

Q = ncΔT


Where n is number of mole of substance


c is molar heat capacity of substance


ΔT is rise in temperature


Given,


c = 24 J mol-1 K-1


ΔT = 55 – 35 = 20°C = 20 K


m = 60 g


number of mole of Aluminium in m gram is given as


n = m/M


Where M is molar mass of aluminium.


n = 60/27 = 2.22


Thus Q = ncΔT


= (2.22 mol)×(24 J mol–1 K–1)×(20K)


= 1065.6 J


= 1.065 kJ


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