1 [CO. [NOCl] 2. [HBr] Equilibrium Constant, Keq

Transcription

1 quilibrium onstant, 1. Once a system has reached uilibrium, are the following true or false? a. The reaction is finished, no more products are forming. false b. The concentrations of the reactants and the products are ual. false c. The concentrations are no longer changing. false d. The reaction is not over, but will continue forever if isolated. true e. The speed at which products are made uals the speed at which reactants form. true. What is ual at uilibrium? rate forward rate reverse 3. What general information can be gathered by observing the magnitude of the uilibrium constant? Whether the reactants or products are favoured. 4. Write the expression for for the reaction : NO (g) + l (g) NOl (g) [NOl [NO [l. Write the for: 3 PO 4 (aq) + 3 a(no 3 ) (aq) 6 NO 3 (aq) + a 3 (PO 4 ) (s) 6 [NO3 3 [3PO4 [a(no3) 6. Write the expression for for the reaction : H (g) + Br (l) HBr (g) [HBr [H 7. Write the expression for for the reaction: O (g) + ao (s) ao 3 (s) 1 [O 8. For the reaction: SiH 4 (g) + O (g) SiO (g) + H O (l) a) Write the uilibrium expression for the forward reaction: [SiO [SiH [O 4 b) Write the uilibrium expression for the reverse reaction: [SiH4[O 1 ' [SiO

2 c) What is the uilibrium constant in the forward direction if [SiH 4.4M; [O.M; and [SiO.1M at uilibrium? [SiO [SiH4[O (.1) (.4)(.).3 d) What is the uilibrium constant in the reverse reaction? e) If [SiH 4.34M; [O.M and [SiO.3M, what would be the reaction quotient (Q) in the forward direction and which direction will the reaction go? (.3)(.).8 (.34)(.) Q.8 >.3 then the reaction will go towards the reactants alculating, Q, I tables 9. alculate the uilibrium constant for this reaction: PO Br (aq) PO (aq) + Br (aq) Given: [PO Br.M, [PO.1M, and [Br.31M at uilibrium. PO Br PO Br (.1) (.31).13 (.) + [PO [Br [PO Br 1. For the combination reaction: H (g) + F (g) HF (g), calculate all three uilibrium concentrations when [H i [I i. M and 64.. [HF H + F HF 64. [H[F I.. Q <.. (x) 64. (. )(. ) (x) (. )(. ) perfect square Rule - doesn' t apply..31 < 1 64.

3 [H heck : x 8.. x x 1.x x [F M and [HF (.3) Q (.4) 64. (.16).3 M 11. For the decomposition reaction, Ol (g) O (g) + l (g), calculate all three uilibrium concentrations when.68 with [O i. and [l i 1. M. Ol O + l [O[l [Ol.68 I. 1. Q undef > 1 Rule - doesn't apply < 1.68 (. )(1. ).68 x. - 1.x.68 x x -.18x +. a 1 b -.18 c. -(-.18) ± x.18 ± 1.66 x x 1.9 (too big) or x.6 [Ol.6M, [O M and [l M heck : Q (.4)(.74).683 (.6)

4 1. We place.64 mol N O 4 (g) in a 4. L flask at. After reaching uilibrium, the concentration of NO (g) is.3 M. What is for the reaction N O 4 (g) NO (g)? [NO NO4 NO [NO4 I but [NO.3 M x.3 x.1 (.3) 6.1x 1 ( ) 13. arbonyl bromide decomposes to carbon monoxide and bromine: OBr (g) O(g) + Br (g) is 1.9 x 1 at 73 o. If an initial concentration of.33 M OBr is allowed to uilibrate, what are the uilibrium concentrations of OBr, O, and Br? I OBr [OBr heck : ( )( ).3 x O x (.7) Q x 1.7 x 1 7. x Br 1.93 x M,[O [O[Br 1.9 x 1 [OBr x 1 Q < 1 Rule - applies [l 179 > 1.7 M

5 14. Pl decomposes into Pl 3 and l gas. What is the initial concentration of Pl if at uilibrium the concentration of chlorine gas is.m? Given: 1. (Hint: I table) I Pl y y and [l [Pl i heck : Q Pl 3.M x. M and [Pl + (.)(.) y -. (.)(.). Le hatelier s Principle l 1. 1.y. y y [Pl3[l [Pl. M onsider this endothermic reaction: 3 O (g) O 3 (g). To shift this reaction to the reactants: a) You could the pressure. (decrease) b) You could the volume. (increase) c) You could oxygen gas. (remove) d) You could the temperature. ( increase or decrease) e) Which of the following, if increasing, will change the value of the uilibrium constant? d) Temperature 16. onsider this reaction: SO (g) + O (g) SO 3 (g). To shift this reaction towards the products: a) You could the pressure. (increase) b) You could the volume. (decrease) c) You could oxygen gas. (add) 17. For each system described below, indicate in which direction the uilibrium will shift when each stress is added or removed. a) N (g) + 3 H (g) NH 3 (g): more H is added to reaction at uilibrium. ( ) b) For the same reaction, some NH 3 is removed from the reaction at uilibrium. ( )

6 c) SO (g) + O (g) SO 3 (g) + heat: heat is added. ( ) d) Using the same reaction, heat is removed ( ) e) Pl 3 (g) + l (g) Pl (g): volume is reduced by half. ( ) f) Using the same system as above, a catalyst is added to the system. (same) g) H (g) + l (g) Hl (g): volume is doubled. (same) h) Using the same system as above, some neon is added to the system. (same) 18. xplain how the following changes in reaction conditions will affect the position of the uilibrium: A (g) + B (aq) (s) _H rxn 3 kj/mol a) The pressure of A in the reaction chamber is increased. ( ) b) The temperature of the reaction is increased by. ( ) c) A catalyst is added to the system. (same) d) More of compound B is steadily added to the reaction chamber. ( ) e) More of compound is steadily added to the reaction chamber. (same) f) Argon gas is added to the reaction chamber, doubling the pressure. (same)