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QUESTION 5 The equilibrium constants of four different reactions are given. In which reaction does the equilibrium lie furthest to the left? PCIs(e) + Ch(g) = PCIe) AgI0;(s) = Agt (aq) + IO; (aq) s0 x fo Cl (g) + H O() = HOCI(aq) + Cl(aq) + H*(aq) HSO; (aq) + H O(1) = H30* (aq) + SO37(aq)
QUESTION 14 Ammonia gas reacts with oxygen gas in the following equilibrium reaction. 4NH (g) + 302(g) = 2N2(g) + 6H20(g) The equilibrium expression for the reaction is (A) (B) (C) (D) [NH3][05] a N ][H0] [N>][H 0] [NH3][05] [NH3]*[0 ]ÔøΩ [N2]ÔøΩ[H0]? [N2}ÔøΩ[H20]ÔøΩ [NH3]*[03}ÔøΩ
QUESTION 2 (12 marks) Salicylic acid reacts with ethanoic anhydride in an aqueous solution to produce acetylsalicylic acid as shown in the equation. Acetylsalicylic acid is commonly known as aspirin. a) b) Cc) d) e) O On i O C CH /&ÔøΩ CH 3 7 ÔøΩ + CÔøΩOH As = CH-CÔøΩOH I ee: CÔøΩOH 3 O salicylic acid ethanoic anhydride acetylsalicylic acid ethanoic acid (C H 05) (C H 03) (C H O0 ) (C H 0 ) Identify the type of chemical reaction used to produce aspirin. [1 mark] Write the equilibrium expression K for the reaction. [1 mark] At 20 ÔøΩC the equilibrium constant (K ) for the reaction is 2 x 10ÔøΩ. Determine whether the concentration of the reactants or products is greater at equilibrium at this temperature. [2 marks] Calculate the minimum mass of salicylic acid required to produce 500.0 mg of aspirin if the yield of aspirin 1s 45.0%. Show your working. [4 marks] mg (to three significant figures) When the reaction is heated to 40 ÔøΩC and equilibrium is re-established the concentration of acetylsalicylic acid and ethanoic acid increases. Apply Le ChatelierÔøΩs principle to predict if the forward reaction is exothermic or endothermic. Explain your reasoning. [4 marks]
QUESTION 5 (17 marks) Compound A reacts with water to produce compound B and hydroxide ions. a) b) c) d) e) CH CH NH (aq) +H O(l) f C HsNH{ (aq) + OH (aq) A B Apply IUPAC rules to name compound A. Identify the Brensted-Lowry acids in the equation. A small amount of hydrochloric acid is added to the equilibrium mixture. Predict the effect of this on the concentration of compound A in the mixture. Explain your reasoning. Calculate the pH of a 2.0 M solution of compound A. State any assumptions. Show your working. (K =5.6x10-*) (to one decimal place) Describe using a balanced chemical equation how Compound A could be made from bromomethane. Include relevant conditions and reagents in your response. [1 mark] [2 marks] [3 marks] [6 marks] [5 marks]
QUESTION 26 (5 marks) The graph represents changes in concentration over time for three gaseous molecules (X Y and XY) in a closed system at constant temperature and pressure. X +Y = 2XY Concentration (mol L) Time a) Identify whether XY is the reactant or the product. [1 mark] b) Calculate the equilibrium constant (K ) value. [2 marks] (to two significant figures) c) Determine whether the position of equilibrium favours the reactants or products. Explain your reasoning. [2 marks]
QUESTION 4 (9 marks) 5.00 x 1074 moles of hydrogen gas 1s mixed with 1.00 x 10> moles of iodine vapour in a sealed 1.00 L vessel at 455.0 ÔøΩC. The concentration of hydrogen iodide gas formed at equilibrium is 9.30 x 104+ M. The balanced equation for the reaction is shown. H (g)+ L(g) = 2HI(g) a) Write the equilibrium law expression for the reaction. [1 mark] b) Calculate the equilibrium constant (K ) for the reaction at 455.0 ÔøΩC. Show your working. [5 marks] (to three significant figures) c) Predict the effect that adding a catalyst would have on the reaction rates position of the equilibrium and value of K . [3 marks]
QUESTION 25 (5 marks) Three unknown gases are combined in a sealed flask and allowed to reach equilibrium as shown by the equation. 3A (g)+X(g) = 2XA;3(g) a) Determine whether the gases reach a state of dynamic equilibrium. Explain your reasoning. [3 marks] b) Determine if the relative position of equilibrium lies towards the products or reactants if the molar concentrations at equilibrium are 3.4 mol L! for A> 1.8 mol L! for X> and 4.2 mol L! for XA. Explain your reasoning. [2 marks]
QUESTION 2 (8 marks) The reaction shows part of the contact process used to produce sulfuric acid. 280; (g) +O; = 280; (g) The equilibrium constant (X ) for this reaction at different temperatures is shown. Temperature (K) | Equilibrium constant K (mol L) 298 9.77 x 107ÔøΩ 500 8.61 x 10!! a) Deduce if the forward reaction is exothermic or endothermic. Explain your reasoning. [2 marks] b) Calculate the equilibrium concentration of SO; at 500 K given the equilibrium concentrations. [SO ] = 0.860 M; [O ] = 0.330 M [2 marks] Concentration = M (to three significant figures) c) Apply Le ChatelierÔøΩs principle to explain whether halving the reaction vesselÔøΩs volume at 500 K would affect the position of the equilibrium or the value of the equilibrium constant. [4 marks]
QUESTION 5 Determine the equilibrium expression (K ) for the reaction. 2HI(g) = Hg) + L(g) Colourless Colourless Purple _ [Fo I[b] (B) K _[Ho|[h] [Hy _ 2[8)2{1) (C) K = 2[HI] » x -2HEE AH = +53.6 kJ mol!
QUESTION 8 (7 marks) Two experiments were conducted to investigate the effect of temperature on the equilibrium formed during the decomposition of hydrogen iodide (HI). 2HI(g) = H (g) + L(g) AH = +53.6kJ mol! a POD Coma On Equilibrium concentration a L 1) (mol L) K cm fn [er fm Tt [| Experiment P80 fom 900 [om fa [a0 Fons [06 [ae [oa aoe (a) Determine the concentration of HI(g) and I (g) at equilibrium for experiment 1. [2 marks] [HI]: [In]: (b) Calculate the equilibrium constant (K ) for experiment 2. Show your working. [2 marks] (c) Determine which experiment was conducted at a higher temperature. Explain your reasoning. [3 marks]
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