Reaction Table of contents Table of Contents Table of Contents Section 1Table of ContentsTable of Contents Opening the Reaction module Opening the Reaction module Section 2Opening the Reaction moduleOpening the Reaction module Pure substance property calculations (pure Cu) Pure substance property calculations (pure Cu) Section 3Pure substance property calculations (pure Cu)Pure substance property calculations (pure Cu) Isothermal standard state reactions (oxidation of copper) Isothermal standard state reactions (oxidation of copper) Section 4Isothermal standard state reactions (oxidation of copper)Isothermal standard state reactions (oxidation of copper) Using non-standard states in equilibrium reaction Using non-standard states in equilibrium reaction Section 5Using non-standard states in equilibrium reactionUsing non-standard states in equilibrium reaction Non-isothermal non-equilibrium calculation (heating of pure (Al)) Non-isothermal non-equilibrium calculation (heating of pure (Al)) Section 6Non-isothermal non-equilibrium calculation (heating of pure (Al))Non-isothermal non-equilibrium calculation (heating of pure (Al)) Two phase single component equilibrium (ideal binary system) Two phase single component equilibrium (ideal binary system) Section 7Two phase single component equilibrium (ideal binary system)Two phase single component equilibrium (ideal binary system) Variable input amounts in non-isothermal reaction Variable input amounts in non-isothermal reaction Section 8Variable input amounts in non-isothermal reactionVariable input amounts in non-isothermal reaction Pidgeon Process for the Production of Magnesium Pidgeon Process for the Production of Magnesium Section 9Pidgeon Process for the Production of MagnesiumPidgeon Process for the Production of Magnesium Aqueous applications Aqueous applications Section 10Aqueous applicationsAqueous applications Complex gases and condensed substances under high pressure Complex gases and condensed substances under high pressure Section 11Complex gases and condensed substances under high pressureComplex gases and condensed substances under high pressure Reaction calculates the thermochemical properties of a species, a mixture of species or a chemical reaction. Reaction accesses only compound databases. Reaction assumes all gases are ideal and ignores expansivities and compressibilities of solids and liquids. The Reaction module 1

Reaction The Reaction module 2 Click on Reaction in the main FactSage window.

Reaction Reactants window - entry of a species (pure Cu) Reaction has two windows – Reactants and Table 3.1 Entry of reactant species Compound databases available Go to the Table window New Reaction Open Add a Reactant Add a Product Reaction can only access compounds (not solutions) All calculations shown here use the FACT compound databases and are stored in FactSage - click on: File > Directories… > Slide Show Examples …

Reaction Table window – thermodynamic properties of a species New Reaction Open Save Stop Calculation Summary of the Reactants window Return to the Reactants window A multiple entry for T: min, max and step. The results also display the calculated transition temperatures. 3.2

Reaction Determination of most stable phase by Gibbs energy minimization Phase with lowest Gibbs energy is the most stable J J K K Points on the solid lines for P = 1 atm are given in column «T» and «G» of the previous figure for copper. 3.3

Reaction This example is stored in FactSage. Go to the menu bar and click on: File > Directories… > Slide Show Examples and select file 2. Simple isothermal standard state reaction: oxidation of copper Entry of an isothermal standard state reaction: 4 Cu + O 2 = 2 Cu 2 O Isothermal “T” throughout Non standard states checkbox is not selected 4.1 Go to the Table window

Reaction Oxidation of copper at various temperatures Entry: T min =300K, T max =2000K and step=300K. Note the transition temperatures. The equilibrium constant column appears for an isothermal standard state reaction.  G º = -RT lnK. For the values of the gas constant R, click on the Units menu. 4.2

Reaction Simple chemical equilibrium: non standard state oxidation of copper P O 2 (g) = “P” Standard state reaction: P O 2 (g) = 1.0 atm a Cu(s) = Select non standard state a Cu(s) = “X”

Reaction Specifying an extensive property change to deal with chemical equilibrium For simple chemical equilibrium: and  G 0 = -RT ln K eq Table provides  G using: and when  G = 0. For the last entry: P O 2 (g) = a Cu(s) = 1  G = 0, equilibrium 5.2

Reaction Heating Al from 300 K to the temperature T phase transition, Al (s)  Al (l) (i.e. fusion) at K  H° fusion = T fusion  S° fusion = J J = J 6.1 The equilibrium constant is not displayed because this is a non-isothermal non- equilibrium calculation.

Reaction Heating Al: creating the graphical display with Figure 1. Click on the menu Figure and select Axes A dialog box opens and provides you with a choice of axes for the figure. 6.2 Click on Refresh for the default settings

Reaction Heating Al: graphical display of thermodynamic properties 933 K solid liquid Point the mouse to read the coordinates of the melting point kJ 6.3

Reaction Computation of Cu liquidus in an ideal binary system: data entry Cu(solid) = Cu(liquid) a Cu(liquid) = X 7.1 Equilibrium of the type: Me(pure solid,T) = Me (liquid,a(Me) = x(Me),T) a Cu(solid) = 1, pure solid copper Selection of phases: phases from the FACT database; 2 compound databases are included in the Data Search but here only FACT data are selected.

Reaction Computation of Cu liquidus in an ideal solution: mixing databases 3. Follow the instructions if you want to add (or remove - this does not delete) a database to (or from) your list Click on the Data Search menu. 2. FACT and SGPS compound databases are selected

Reaction Computation of Cu liquidus in an ideal binary system: tabular and graphical output Calculated activity of Cu(liquid) in equilibrium (  G=0) with pure Cu(solid) at various temperatures T. Liquid Liquid + Solid Liquidus line For an ideal solution: a Cu(liquid) = X Cu(liquid) The 2 specified variables, T and  G, are highlighted. Note: When  G = 0, the reaction must be isothermal. 7.3

Reaction 8.0 Variable input amounts in non-isothermal reaction and autobalance feature The following example shows how a variable amount of a reactant can be used to simulate an excess of this substance, i.e. its appearance among both the reactants and the products. A simple combustion reaction: CH 4 + O 2 = CO H 2 O + O 2 The Alpha variable,, is used to define the quantity of O 2.

Reaction Combustion of CH 4 in variable amount O 2 – data entry Variable quantity The reactants are at 298 K but the products are at an unspecified T. 8.1 The phase of each species is specified. The reaction is non-isothermal (except when T = 298 K). Hence: K eq will not appear as a column in the Table window. Setting  G = 0 is meaningless ( except when T = 298 K).

Reaction Combustion of CH 4 in variable amount O 2 – adiabatic reactions Stoichiometric reaction (A = 2): CH O 2 = CO H 2 O Reaction with variable amount O 2 (A > 2): CH 4 + (A) O 2 = CO H 2 O + (A + excess) O 2 Exothermic reaction Adiabatic reaction:  H = 0 Product flame temperature As increases, the flame temperature decreases. Energy is required to heat the excess O

Reaction Heating the products of the methane combustion. Reaction «auto-balance» feature 8.3

Reaction Step wise heat balance in treating methane combustion 2000 K 298 K Different thermodynamic paths, same variation of extensive properties (here  H). Overall Process  H = J Warming Products  H = J Isothermal Reaction Heat  H = J 8.4

Reaction Pidgeon Process for the Production of Magnesium MgO-SiO 2 phase diagram: Note: MgO(s) and SiO 2 (s) can not coexist – they react to form (MgO) 2. SiO 2. Equilibrium Mg partial pressure developed at the hot end of the retort Apparatus Schema: Water-cooled vacuum connection also condenses alkalis 1423 K 9.1

Reaction Pidgeon Process for the Production of Magnesium: Data Entry In the reaction, the hydrostatic pressure above the condensed phases: MgO(s), Si(s) and SiO 2 (s2) is 1 atm – i.e. has no effect. Allotrope s2(solid-2) has been selected for SiO 2 in order to fully specify the phase – if the phase is not completely specified, equilibrium calculations (  G = 0) can not be performed. 9.2 The partial pressure of Mg (g) is: P Mg (g) = P atm. The activity of SiO 2 is: a SiO 2 = X. The reaction is isothermal (same “T” throughout), hence  G = 0 gives equilibrium.

Reaction Equilibrium Mg partial pressure developed at the hot end of the retort When  G=0, T=1423 K and a SiO 2 (s2) = then P Mg(g) eq = × atm. This value of a SiO 2 (s2) is taken from the next page calculation. At equilibrium(  G=0), when P Mg eq =1atm and T=1423 K, a SiO 2 (s2) eq = × Standard state reaction at 1423 K: P Mg eq = 1 atm and a SiO 2 (s2) = 1  G º = kJ = -RT ln K eq, hence K eq = ×  G º > 0 but Mg can be produced by reducing P Mg(g) and/or a SiO 2. At equilibrium(  G=0), when a SiO 2 (s2) =1.0 and T=1423 K, P Mg eq = × atm Note:There are an infinite number of values of (P Mg(g), a SiO 2 (s2) ) which satisfy K eq. Here we select 3 special cases. 9.3

Reaction Computation of SiO 2 activity when MgO coexists with (MgO) 2 SiO 2 Pure MgO Pure (MgO) 2 SiO 2 SiO 2 (s2) at activity X Isothermal… …and at equilibrium Gives the equilibrium value of the activity of SiO 2 (s2) at 1423 K: a SiO 2 (s2) =

Reaction Alternative way to calculate equilibrium Mg partial pressure Remember,  G = 0 (equilibrium) calculations are only meaningful for isothermal reactions («T» throughout). Magnesium production is enhanced by: reducing the total pressure (< atm); reducing a SiO 2 – this is done automatically due to (MgO) 2 SiO 2 formation, but the addition of say CaO (slag formation) reduces a SiO 2 further. 9.5

Reaction Aqueous applications – hydrogen reduction of aqueous copper ion 10.1 Click on Units to change Temperature to Celsius. The molality of Cu 2+ is given by “X”. H 2 (g) pressure is “P” atm.

Aqueous applications – hydrogen reduction of aqueous copper ion Standard state reaction at various temperatures Equilibrium molality at various P H 2 Click on Output to change display to E(volts) and define n, the number of electrons Standard state reaction at 25 ° C Eº=-  G°/nF, where F (= C/mol) is the Faraday constant. Reaction 10.2

Reaction Thermal balance for leaching of zinc oxide This entry calculates the product temperature for an adiabatic reaction:  H = The reaction is exothermic:  H < 0.

Reaction 11.0 Complex gases and condensed substances under high pressure The following two slides show how Reaction is used on a system with polymer formation in the gas phase (Na(l) ↔ Na 1 + Na 2 ) and on a pure substance system that is submitted to very high pressure (C).

Reaction Computation of Na and Na 2 partial pressure in equilibrium with liquid Na 3.Calculate P Na 2 when T=1158 K Na also forms a gaseous dimer Na 2 (g). The proportion of Na 2 /Na near the boiling point ( K) of Na is: 0.111/0.888 at 1158 K; and the total vapor pressure over Na(l) would be: P Na + P Na 2 (  1). 2 Na (l)  Na 2(g) (dimer) 11.1 Both reactions are isothermal, hence  G=0 gives equilibrium. Na (l)  Na (g) (monomer) 1.Calculate T when P Na = 1 atm 2.Calculate P Na when T = 1158 K

Reaction Effect of high pressure on the graphite to diamond transition The volume of diamond is smaller than graphite. Hence, at high pressures, the “VdP” term creates a favorable negative contribution to the enthalpy change associated with the graphite  diamond transition. Where available, density (i.e. molar volume) data for solids and liquids are employed in REACTION (the “VdP” term) although their effect only becomes significant at high pressures. (However, unlike EQUILIB, compressibility and expansivity data are NOT employed.) (  G =0) At 1000 K and atm, graphite and diamond are at equilibrium (  G =0) 11.2 Here, carbon density data are employed to calculate the high pressure required to convert graphite to diamond at 1000 K.