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 the units header

3 Enter a temperature Hit calculate

4 the reaction changes in thermodynamic properties for the reaction at 700°C Why is ΔH negative? Why is ΔG negative?

5 Enter a single reactant to calculate ABSOLUTE thermodynamic properties Absolute Properties

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

7 When does absolute H = 0? When does absolute S = 0? Absolute thermodynamic properties for Na. Note phase changes from solid to liquid to gas.

8 Plotting results in a figure Click Figure, then AxesYou must have more than one point to plot a figure

9 Click Y-variable Select thermodynamic function and scaleRepeat for X-variable Adjust the range and increment Press OK

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

11 How to calculate the effect of temperature or pressure changes Initial temperature Final temperature

12 Delta properties

13 How to calculate properties of a physical change – melting, evaporation change of phase, constant T

14 When does ΔG = 0? at 900°C, ΔG becomes negative

15 At °C, liquid Na is in equilibrium with 1 atm of Na vapor Leave T blank and enter zero for ΔG

16 What temperature is achieved if the reaction is adiabatic? We assume it’s hot enough to vaporize NaCl reactant and product temperatures are different

17 Note 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

18 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.

19 for equilibrium, set ΔG = 0 1.To determine the partial pressure of chlorine, enter T and x below 2.To determine the activity of sodium, enter T and P below 3.To determine the equilibrium temperature, enter P and x below

20 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?

21 We can lower the boiling point by decreasing the pressure vapor-liquid equilibrium

22 vary the pressure in steps of -0.2 atm and set ΔG=0 as pressure decreases, the boiling temperature drops

23 P-T relation for equilibrium between phases

24 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 equilibriumvariable activity

25 as activity decreases, the melting temperature goes down