Question

What is the heat required to melt 62.0 g of solid ammonia, NH₃, at its melting point? The ΔH° of fusion of ammonia is 5.97 kJ/mol. Use a molar mass with at least as many significant figures as the data given.

 Answer in kJ units

Answer 1

Given

$\Delta H_f=5.97kJ/mol=5.97 \times\dfrac{1}{17.03}kJ/gm=0.35 kJ/ gm$

Now

$Q=m\Delta H_f$

$Q=62 \times0.35=21.7 kJ$