HI Equilibrium

The first in a series of models which use "real" rate constants and equations to allow students to explore equilibrium. The model builds on the earlier HI stoichiometry model. Students should recognise that the moles of reactant can be used because the volume of the reaction will remain the same and thus including the volume will not alter the results. If desired for consistency, it is easy enough to add volume to the calculations, but the model can get ugly.

The constants used here are for the reaction at 700K. Here are some other values:

T(K)kfkrK
3002.24e-192.04e-16912
4002.46e-116.69e-9371
5001.66e-62.14e-4129
6002.75e-32.14e-177.8

Students can use these values to explore various aspects of equilibrium. Be forewarned, when changing the rate constants, it may be necessary to change the time specs of the model.

STELLATM software is needed to view the model in Mac (hqx) format or PC format.

[Diagram Level | Equations Level | Graphs ]

```moles_HI(t) = moles_HI(t - dt) + (I2_to_HI + H2_to_HI - HI_to_H2 - HI_to_I2) * dt
INIT moles_HI = initial_mol_HI

INFLOWS:
I2_to_HI = rate_reverse
H2_to_HI = rate_reverse
OUTFLOWS:
HI_to_H2 = rate_forwd
HI_to_I2 = rate_forwd
moles_hydrogen(t) = moles_hydrogen(t - dt) + (HI_to_H2 - H2_to_HI) * dt
INIT moles_hydrogen = initial_mol_H2

INFLOWS:
HI_to_H2 = rate_forwd
OUTFLOWS:
H2_to_HI = rate_reverse
moles_iodine(t) = moles_iodine(t - dt) + (HI_to_I2 - I2_to_HI) * dt
INIT moles_iodine = initial_mol_I2

INFLOWS:
HI_to_I2 = rate_forwd
OUTFLOWS:
I2_to_HI = rate_reverse
initial_mol_H2 = 0.1
initial_mol_HI = 0.1
initial_mol_I2 = 0.1
Keq = moles_hydrogen*moles_iodine/moles_HI^2
k_forward = 0.550
k_rev = 30.2
rate_forwd = k_forward*moles_HI^2
rate_reverse = k_rev*moles_iodine*moles_hydrogen
total_moles = moles_HI+moles_hydrogen+moles_iodine

```
##### Time Specs
Range: 0-100 , dT = 0.1 , Integration Method = RK4

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