Question:
Using equipartition of energy, the specific heat (in J kg-1 K-1) of aluminium at room temperature can be estimated to be (atomic weight of aluminium = 27)
Using equipartition of energy, the specific heat (in J kg-1 K-1) of aluminium at room temperature can be estimated to be (atomic weight of aluminium = 27)
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A solid atom has 6 quadratic energy terms (3 kinetic + 3 potential), so C = 3R per mole; divide by the molar mass in kg.
Updated On: Nov 11, 2026
- 25
- 410
- 925
- 1850
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The Correct Option is C
Solution and Explanation
In a solid each atom has 3 vibrational degrees of freedom, each carrying \(2\times\frac12 k_BT\) of energy, so the energy per mole is \(3RT\) and the molar heat capacity is \(3R\approx 24.9\ \mathrm{J\,mol^{-1}K^{-1}}\) (Dulong-Petit).
Per kg: \(c=\frac{3R}{M}=\frac{3\times8.31}{27\times10^{-3}}\approx 923\ \mathrm{J\,kg^{-1}K^{-1}}\approx 925\).
Answer: (3) 925
Per kg: \(c=\frac{3R}{M}=\frac{3\times8.31}{27\times10^{-3}}\approx 923\ \mathrm{J\,kg^{-1}K^{-1}}\approx 925\).
Answer: (3) 925
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