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Index/Physical chemistry/CHM-32

CHM-32

van 't Hoff

K vs T.

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Physical chemistryvan't Hoff

Governing equation

ln(K2/K1)=−DeltaH/R(1/T2−1/T1)\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1)

T2∈[250,500]T_2 \in \left[250, 500\right]

where

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

The figure, part by part

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CHM-32 · phase
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①

Governing law — red

ln(K2/K1)=−DeltaH/R(1/T2−1/T1)\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1)

T2∈[250,500]T_2 \in \left[250, 500\right]

T2=250T_2 = 250K2=481.7K_2 = 481.7

②

Domain of the variable — blue

T_2_{\min} = 250,\quad T_2_{\max} = 500

T2∈[250,500]T_2 \in \left[250, 500\right]

T2=250T_2 = 250T2=250T_2 = 250

③

Response curve — green

ln(K2/K1)=−DeltaH/R(1/T2−1/T1)\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1)

T2∈[250,500]T_2 \in \left[250, 500\right]

T2=250T_2 = 250K2=481.7K_2 = 481.7

④

Rate of change — amber

dK2dT2\frac{\mathrm{d}K_2}{\mathrm{d}T_2}

T2∈[250,500]T_2 \in \left[250, 500\right]

T2=251.6T_2 = 251.6K2′=−39.57K_2^{\prime} = -39.57

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: K1K_1, T1T_1, T2T_2, ΔH\Delta H →\rightarrow K2K_2. K vs T.

Purpose

Purpose: compute K2K_2 from K1K_1, T1T_1, T2T_2, ΔH\Delta H in Physical chemistry via ln(K2/K1)=−DeltaH/R(1/T2−1/T1)\\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 K1=10.000 —K_1 = 10.000\,\mathrm{—}, T1=298.000 KT_1 = 298.000\,\mathrm{K}, T2=350.000 KT_2 = 350.000\,\mathrm{K}, ΔH=−50.000 kJ/mol\Delta H = -50.000\,\mathrm{kJ/mol}, the governing relation ln(K2/K1)=−DeltaH/R(1/T2−1/T1)\\ln(K_2/K_1)=-\\Delta H/R(1/T_2-1/T_1) yields K2=0.4987 —K_2 = 0.4987\,\mathrm{—}. K vs T. Move a slider: the numbers are this situation, not a canned story.

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Outputs

  • K2 K_20.4987 —
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CHM-32 · phase
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Narration of this film

K vs T.

K vs T.

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