1 The Reaction Program. 2 Add species windows by clicking + Enter a balanced reaction. Leave Phase...

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1 The Reaction Program

description

3 Enter a temperature Hit calculate

Transcript of 1 The Reaction Program. 2 Add species windows by clicking + Enter a balanced reaction. Leave Phase...

Page 1: 1 The Reaction Program. 2 Add species windows by clicking + Enter a balanced reaction. Leave Phase as most stable. Press Next Units can be changed from.

1

The Reaction Program

Page 2: 1 The Reaction Program. 2 Add species windows by clicking + Enter a balanced reaction. Leave Phase as most stable. Press Next Units can be changed from.

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Add species windows by clicking +

Enter a balanced reaction. Leave Phase as most stable.

Press Next

Units can be changed from the units header

Page 3: 1 The Reaction Program. 2 Add species windows by clicking + Enter a balanced reaction. Leave Phase as most stable. Press Next Units can be changed from.

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Enter a temperature

Hit calculate

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the reaction

changes in thermodynamic properties for the reaction at 700°C

Why is ΔH negative? Why is ΔG negative?

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Enter a single reactant to calculate ABSOLUTE thermodynamic properties

Absolute Properties

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Enter initial, final and incremental values for a series of temperatures

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7When does absolute H = 0? When does absolute S = 0?

Absolute thermodynamic properties for Na. Note phase changes from solid to liquid to gas.

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Plotting results in a figure

Click Figure, then Axes You must have more than one point to plot a figure

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Click Y-variable

Select thermodynamic function and scale Repeat for X-variable

Adjust the range and increment

Press OK

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10Note phase transitions at the inflection points of the Gibbs energy function

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How to calculate the effect of temperature or pressure changes

Initial temperature

Final temperature

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Delta properties

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How to calculate properties of a physical change – melting, evaporation

change of phase, constant T

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When does ΔG = 0?

at 900°C, ΔG becomes negative

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At 898.65°C, liquid Na is in equilibrium with 1 atm of Na vapor

Leave T blank and enter zero for ΔG

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What temperature is achieved if the reaction is adiabatic?

We assume it’s hot enough to vaporize NaCl

reactant and product temperatures are different

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17Note that all phases must be specified in order to enter values for ΔG, ΔH, etc.

Hotter than normal boiling point of Na

enter 0 for adiabatic reaction

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Non-standard States

Check the non standard states box to enter values for pressure and activity. To make them variables, enter P for pressure or x for activity.

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for equilibrium, set ΔG = 0

1. To determine the partial pressure of chlorine, enter T and x below2. To determine the activity of sodium, enter T and P below3. To determine the equilibrium temperature, enter P and x below

1.2.3.

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Liquid

Gas

Bi + Cd

Bi - Cd1 atm

mole fraction Cd

T(C

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0 0.2 0.4 0.6 0.8 10

200

400

600

800

1000

1200

1400

1600

The Bi-Cd phase diagram consists of a vapor phase, a liquid solution and pure solid metals. What can we change to lower the boiling point of Cd? Second, what can we change to lower the melting point of Cd?

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We can lower the boiling point by decreasing the pressure

vapor-liquid equilibrium

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vary the pressure in steps of -0.2 atm and set ΔG=0

as pressure decreases, the boiling temperature drops

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P-T relation for equilibrium between phases

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Pressure has very little effect on melting point. However, lowering the activity of Cd by putting it in a liquid will decrease the melting point, but only up to the eutectic.

solid-liquid equilibrium variable activity

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as activity decreases, the melting temperature goes down