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Question 9 of 10 The equilibrium constant, K, of a certain first order reaction

ID: 985870 • Letter: Q

Question

Question 9 of 10 The equilibrium constant, K, of a certain first order reaction was measured at two temperatues, T. If you were going to graphicaly determine the enthalp r, for this reaction, what points would you plot? The data is shown in this table T (K) K 225 825 511 To avoid rounding errors, use threo significant figures in the x values and four significant figures in the y vaues point 1: 3.85 point 2: n Determine the rise, run, and slope of the line formed by these points. nso run slope What is the standard enthalpy of this reaction? J/mol

Explanation / Answer

Data

T(K)      K

225    3.85

825    5.11

For graph,

                         x (1/T)                           y (lnK)

point 1:            0.00444444                   1.3481

point 2:            0.00121212                   1.6312

Determination of rise, run, slope

rise = y2-y1 = 1.6312 - 1.3481 = 0.29

run = x2-x1 = 0.00121212 - 0.00444444 = -0.0032323    

slope = rise/run = 0.29/-0.0032323 = -89.72

Standard enthalpy of reaction,

dHo = -slope x R = -(-89.72) x 8.314 = 745.93 J/mol