Question

The equilibrium constant K for a certain reaction was measured as a function of temperature (in Kelvin). A plot of ln(K) versus 1/T for this reaction gives a straight line with a slope of 1.352 times 10^4 K and a y-intercept of -14.51. Determine the value of Delta H degree for this reaction -120.6 kJ/mol -164.7 kJ/mol -112.4 kJ/mol -176.7 kJ/mol none of the above

Answer 1

The answer is -112.4 kJ/mol

Explanation

This is graph is called Van't Hoff plot

lnKeq = - ∆H°/RT + ∆S°/R

Slope = - ∆H°/R

∆H° = - slope × R

= - (1.352 ×10^4 K × 8.314 ( J/K mol )

= - 1.124 × 10^5 J/ mol

= - 112.4 kJ / mol