The equilibrium constant, K, of a certain first order reaction was measured at t

Question

The equilibrium constant, K, of a certain first order reaction was measured at two temperatures, T. If you were going to graphically determine the enthalpy, AH°, for this reaction, what points would you plot? The data is shown in this table Number Number lo avoid rounding errors, use three significant figures in the x values and four significant figures in the y values point 1: T(K) K 325 775 6.19 3.37 Number Number point 2: Determine the rise, run, and slope of the line formed by these points rise run slope Number Number Number What is the standard enthalpy of this reaction? Number J/ mol

Explanation / Answer

From the Arrhenius equation

ln k2/k1 = (H/R) (1/T1 - 1/T2)

On the graph

Point 1

x1 = 1/T1 = 1/325 = 0.003076

y1 = ln k1 = ln 3.37 = 1.215

Point 2

x2 = 1/T2 = 1/775 = 0.001290

y2 = ln k2 = ln 6.19 = 1.823

Rise = y2 - y1 = 1.823 - 1.215 = 0.608

Run = x2 - x1 = 0.001290 - 0.003076 = - 0.001786

Slope = rise/run = 0.608/(-0.001786) = - 340.42

Slope = - H/R = - 340.42

H = 8.314*340.42 = 2830.3 J/mol

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.