Question

30.4 kJ is required to melt one mole of sodium chloride. The entropy change during melting is 28.4 JK-1 mol-1 . atm The melting point of sodium chloride Calculate is ___ K(Nearest Integer).

Hint:

The melting point of a substance can be calculated by dividing the enthalpy change by the entropy change during melting.

Answer 1

Correct Answer: 1070

Melting Point Calculation

The relationship between enthalpy (ΔH) and entropy (ΔS) during a phase change is:

ΔS = ΔH / T

Rearranging to find the melting point (T_mp):

T_mp = ΔH / ΔS

Substituting the given values:

• ΔH = 30.4 kJ mol^-1 = 30400 J mol^-1
• ΔS = 28.4 J K^-1 mol^-1

T_mp = 30400 / 28.4 = 1070.42 K

The nearest integer value is 1070 K.