CHM-32

van 't Hoff

K vs T.

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Physical chemistryvan't Hoff

Governing equation

\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1)

where

K_1: K1 (—)
T_1: T1 (K)
T_2: T2 (K)
\Delta H: ΔH (kJ/mol)
K_2: K2 (—)

Lecture brief

Historical brief

Ideal-gas law, van ’t Hoff, Nernst, Michaelis–Menten and Clausius–Clapeyron are physical chemistry’s working equations of equilibrium and rate. The lab is pressure, potential and kinetics. This sheet (CHM-32 — van 't Hoff) is the form associated with van't Hoff. Working symbols: $K_1$ , $T_1$ , $T_2$ , $\Delta H$ $\rightarrow$ $K_2$ . K vs T.

Purpose

Purpose: compute

K_2

from

K_1

T_1

T_2

\Delta H

in Physical chemistry via

\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1)

K vs T. Use it when a real physical chemistry question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

K_1 = 10.000\,\mathrm{—}

T_1 = 298.000\,\mathrm{K}

T_2 = 350.000\,\mathrm{K}

\Delta H = -50.000\,\mathrm{kJ/mol}

, the governing relation

\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1)

yields

K_2 = 0.4987\,\mathrm{—}

. K vs T. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

K1 K_110 —T1 T_1298 KT2 T_2350 KΔH \Delta H-50 kJ/mol

Outputs

K2 K_20.4987 —

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Narration of this film

K vs T.

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