Question

3. If equivalent amounts of heat are absorbed by 1 mol of Metal A (molar mass = 78 g/mol) and 1 mol of Metal B (molar mass = 100 g/mol), which shows the greatest rise in temperature? (Hint: Assume the metals obey Dulong and Petit's law.) Explain your reasoning.

Answer 1

According to Dulongs and petit’ s law for a metal

Molar mass ( gm / mol ) x specific heat heat capacity ( J / gm K ) = constant = 25 J / mol K

since molar mass of metal A is greater it will have lesser specific heat capacity And Metal B will have high heat capacity.

heat ( q ) = m x S $\Delta$ T

since same heat is given to both metal $\Delta$ T $\alpha$ ( 1 / m s )

for metal B ( m x s ) > for metal A ( m x s )

so Metal A will show greater rise in temperature