Chemistry part 25, Julia Burdge,2e (2009)

Tham khảo sách 'chemistry part 25, julia burdge,2e (2009)', khoa học tự nhiên, hoá học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | which simplifies to KP where Lin b a. In general Equation An moles of gaseous products moles of gaseous reactants Because pressures are usually expressed in atmospheres the gas constant R is L atm mol K and we can write the relationship between KP and Kc as Equation KP A c L atm K mol X T KP is equal to Kc only in the special case where An 0 as in the following equilibrium reaction H2 g Br g f 2HBr g In this case Equation can be written as KP Kc L atm K mol X 7 KC Keep in mind that KP expressions can only be written for reactions in which every species in the equilibrium expression is a gas. Remember that solids and pure liquids do not appear in the equilibrium expression. Sample Problems and let you practice writing KP expressions and illustrate the conversion between Kc and KP. V J Write KP expressions for a PCl3 g Cl2 g PCl5 g b O2 g 2H2 g 5 2H2O Z and c F2 g H2 g 2HF g . Think About It It isn t necessary for every species in the reaction to be a gas only those species that appear in the equilibrium expression. Strategy Write equilibrium expressions for each equation expressing the concentrations of the gases in partial pressures. Setup a All the species in this equation are gases so they will all appear in the KP expression. b Only the reactants are gases. c All species are gases. P PC J 1 Solution a KP b KP -------- ---- Ppci3 Pci2 Po Pil J 2 2 c Kp Phf 2 XPh Checkpoint Equilibrium Expressions Select the correct equilibrium expression for the reaction H rzr OH a H2O Z H2O eq a -----------2--- H yOH w _ H eq OH- eq c H2O eq c Kc H eq OH- eq d iel -------------- H eq OH- e e Kc H eq Otr eq H O eq 1 Select the correct equilibrium expression for the reaction CaOM CO2 g CaCO3 r a Kc CO l. q _ CaCO3 eq c CaO eq CO2 eq c Kc CO2 eq CaO eq CO2 eq CaCO 0 _ CO2 eq e c CaOlcq CaCO3 eq 604 Practice Problem A Write KP expressions for a 2CO g O2 g 2CO2 g b CaCO3 CaO s CO2 g and c N2 g 3H2 g 2NH3 g . .