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Equilibrium Constant (K eq ). A constant which can tell you which side of an equilibrium is favored under certain conditions. [http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/TB16_03.JPG]. Equilibrium Constant (K eq ). When K eq is large, reaction favors the products.
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Equilibrium Constant (Keq) • A constant which can tell you which side of an equilibrium is favored under certain conditions. [http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/TB16_03.JPG]
Equilibrium Constant (Keq) • When Keq is large, reaction favors the products. [http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_15/FG15_07.JPG]
Equilibrium Constant (Keq) • When Keq is small, reaction favors the reactants. [http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_15/FG15_08.JPG]
Which has the largest Keq? [http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_15/FG15_18-04h.JPG]
[http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/TB19_01.JPG][http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/TB19_01.JPG]
Equilibrium Calculations • The equilibrium constant can be used to calculate the concentrations (Molarity!) when a reaction reaches equilibrium.
Equilibrium Calculations • Example Reaction: • A + B ⇆ C + D “[ ]” means molarity values!!!
Equilibrium Calculations • Reactions with coefficients: • 2 NO2 (g) ⇆ N2O4 (g) Coefficient becomes a power!
Equilibrium Calculations • Include only gases and aqueous solutions (aq): • C (s) + H2O (g) ⇆ CO (g) + H2 (g) Solids not included!
Equilibrium Calculations • Example: • H2 (g) + I2 (g) ⇆ 2 HI (g) • If the concentrations are: • H2=0.10 M • I2=0.10 M • HI=0.20 M • What is Keq?
Reaction Quotient (Q) • Calculation for the reaction and compare to Keqto see if a reaction has reached equilibrium.
[http://cwx.prenhall.com/bookbind/pubbooks/hillchem3/medialib/media_portfolio/text_images/CH14/FG14_03.JPG][http://cwx.prenhall.com/bookbind/pubbooks/hillchem3/medialib/media_portfolio/text_images/CH14/FG14_03.JPG]
Reaction Quotient (Q) • Example: • 2 NO2 (g) ⇆ N2O4 (g) • If the concentrations are: • NO2 = 0.150 M • N2O4 = 0.300 M • What is Q? • If Keq = 4.73, is the reaction at equilibrium?
Reaction Quotient (Q) • Reaction is not at equilibrium… • Q (13.3) > Keq (4.73), so reaction is shifting towards the reactants.