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# 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. - CBSE (Science) Class 11 - Chemistry

ConceptThermodynamics Applications Enthalpy, H - Extensive and Intensive Properties

#### Question

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.

#### Solution 1

From the expression of heat (q),

q = m. c. ΔT

Where,

c = molar heat capacity

m = mass of the substance

ΔT = change in temperature

Substituting the values in the expression of q:

q = (60/27 mol)(24 J mol^(-1) K^(-1))(20K)

q = 1066.7 J

q = 1.07 kJ

#### Solution 2

No. of moles of Al (m) = (60g)/(27 g mol-1) = 2.22 mol

Molar heat capacity (C) = 24  J mol-1 K-1.

Rise in temperature (∆T) = 55 – 35 = 20°C = 20 K

Heat evolved (q) = C x m x T = (24 J mol-1 K-1) x (2.22 mol) x (20 K)

= 1065.6 J = 1.067 kj

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#### APPEARS IN

Solution 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. Concept: Thermodynamics Applications - Enthalpy, H - Extensive and Intensive Properties.
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