{"id":12,"date":"2014-10-21T09:35:01","date_gmt":"2014-10-21T09:35:01","guid":{"rendered":"http:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/?page_id=12"},"modified":"2014-10-21T09:45:29","modified_gmt":"2014-10-21T09:45:29","slug":"equilibrium","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/equilibrium\/","title":{"rendered":"Equilibrium"},"content":{"rendered":"

1.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The reaction between SO2<\/sub> and O2<\/sub> may be described as<\/p>\n

2SO2(g)<\/sub> + O2(g)<\/sub> \u00a02SO3(g)<\/sub>\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/em><\/strong>\u0394H = -196 kJ mol-1<\/sup><\/p>\n

Select the two conditions that will favour a high yield of SO3.<\/sub><\/p>\n

A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Removal of SO2<\/sub><\/p>\n

B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Lower the pressure<\/p>\n

C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Lower the temperature<\/p>\n

D\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Use a catalyst<\/p>\n

E\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Addition of more O2<\/sub><\/p>\n

2.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A chemical reaction has reached dynamic equilibrium at a certain temperature. Which one of following statements is incorrect<\/strong>?<\/p>\n

A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The reaction has stopped completely<\/p>\n

B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The concentrations of the reactants remains constant<\/p>\n

C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Products are continuously being formed<\/p>\n

D\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The rate of the forward reaction is equal to the rate of the reverse reaction<\/p>\n

3.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Three moles of ethanol and three moles of ethanoic acid were reacted together according to the equation<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C2<\/sub>H5<\/sub>OH + CH3<\/sub>COOH\u00a0 \u00a0\u00a0CH3<\/sub>COOC2<\/sub>H5<\/sub> + H2<\/sub>O<\/p>\n

At equilibrium, there was 2 moles each of ethyl ethanoate and water formed. What is the \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 equilibrium constant for this reaction?<\/p>\n

A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4<\/p>\n

B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2<\/p>\n

C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0.25<\/p>\n

D\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0.44<\/p>\n

4.<\/strong> In which of the following would a change in pressure not affect the yield of product<\/p>\n

\u00a0<\/strong><\/p>\n

5.<\/strong> A catalyst is added to a chemical reaction at equilibrium. Which statement about catalysts is correct?<\/p>\n

6.<\/strong> Nitrogen dioxide can be produced in a number of ways but industrially it is produced using the Ostwald process. Inthe first stage of this process nitrogen monoxide is produced by passing over a hot catalyst.<\/p>\n

In the second stage of this process the nitrogen monoxide combines with oxygen in an exothermic reaction to produce nitrogen dioxide.<\/p>\n

What happens to the yield of nitrogen dioxide if the reaction mixture in stage 2 is cooled?<\/p>\n

7.<\/strong> One method used to produce methanol requires synthesis gas. The following equation shows the production of methanol from synthesis gas.<\/p>\n

Which line in the table shows the conditions that would cause the greatest increase in the amount of methanol produced?<\/p>\n

8. <\/strong>If the yield of ammonia at equilibrium is 15% then the equilibrium position lies\u2026<\/p>\n

A <\/strong>well to the right<\/p>\n

B <\/strong>well to the left<\/p>\n

C <\/strong>almost centrally<\/p>\n

D <\/strong>equally to each side<\/p>\n

9.<\/strong> Equilibrium is reached when the rate of the forward reaction\u2026\u2026\u2026\u2026<\/p>\n

\u00a0<\/strong><\/p>\n

A <\/strong>reaches zero<\/p>\n

B <\/strong>reaches its minimum<\/p>\n

C <\/strong>equals the back reaction rate<\/p>\n

D <\/strong>is twice the back reactionrate<\/p>\n

10. <\/strong>If the equilibrium position for a reaction lies well to the right, then the equilibrium mixture will contain\u2026<\/p>\n

\u00a0<\/strong><\/p>\n

A <\/strong>more products than reactants<\/p>\n

B <\/strong>more reactants than products<\/p>\n

C <\/strong>only reactants<\/p>\n

D <\/strong>only products<\/p>\n

\u00a0<\/strong><\/p>\n

11. <\/strong>Starting with NH3<\/sub> rather than N2<\/sub> and H2<\/sub> , would give an equilibrium mixture with..<\/p>\n

A <\/strong>a greater proportion of ammonia<\/p>\n

B <\/strong>less nitrogen<\/p>\n

C <\/strong>the same proportions of all three gases<\/p>\n

D <\/strong>less ammonia than before<\/p>\n

12.<\/strong> Which conditions would give the best yield of Hydrogen at equilibrium in this reaction?<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 CH4<\/sub>(g) + H\u00adO(g)\u2194CO(g) + 3H2<\/sub>(g)\u00a0\u00a0\u00a0 \u0394= +210kJ<\/p>\n

A <\/strong>High temperature and low pressure<\/p>\n

B <\/strong>High temperature and high pressure<\/p>\n

C <\/strong>Low temperature and low pressure<\/p>\n

D <\/strong>Low temperature and high pressure<\/p>\n

\u00a0<\/strong><\/p>\n

13. <\/strong>In which reaction below will a change in pressure have no effect on the composition of the equilibrium mixture?<\/p>\n

A <\/strong>4NH3<\/sub>(g) + 5O2<\/sub>(g) \u2194 4NO2<\/sub>(g) + 6H2<\/sub>O(l)<\/p>\n

B <\/strong>2SO2<\/sub> (g) + O2<\/sub>(g) \u2194 2SO3<\/sub>(g)<\/p>\n

C <\/strong>CO(g) + H2<\/sub>O(g) \u2194 CO2<\/sub>(g) + H2<\/sub>O(g)<\/p>\n

D <\/strong>C2<\/sub>H4<\/sub>(g) + H2<\/sub>O(g) \u2194 C2<\/sub>H5<\/sub>OH(g)<\/p>\n

14.<\/strong> Ammonia gas dissolves in water to form an alkaline solution.<\/p>\n

NH3<\/sub>(g) + H2<\/sub>O(l) \u2194 NH4<\/sub> +<\/sup> (aq) + OH–<\/sup> (aq) \u0394H = -31kJ<\/p>\n

How would each of the following changes affect the position of equilibrium?<\/p>\n

a) <\/strong>Increasing the temperature.<\/p>\n

b) <\/strong>Increasing the pressure. <\/strong><\/p>\n

c) <\/strong>Adding ammonium chloride.<\/p>\n

15.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 The diagram shows the concentrations of hydrogen, iodine and hydrogen iodide for the reaction between hydrogen and iodine.<\/p>\n

Which of the following statements is incorrect<\/strong>?<\/p>\n

A \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the equilibrium lies predominantly to the left<\/p>\n

B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 at point A on the time axis, the concentration of all three gases is zero<\/p>\n

C \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The reaction between the gases reaches equilibrium at point B.<\/p>\n

D\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Adding more hydrogen at point D will alter\u00a0\u00a0 the shape of the graph.<\/p>\n

E\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 At point C, the system is in a state of dynamic equilibrium.<\/p>\n

16.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 Consider the following equilibrium reaction
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0
\nWhich one of the following will cause a yellow colour to predominate?<\/p>\n

A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Addition of sodium hydroxide (NaOH)<\/p>\n

B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Addition of sodium chromate (Na2<\/sub>CrO4<\/sub>)<\/p>\n

C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Addition of hydrochloric acid (HCl)<\/p>\n

D\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Removal of water<\/p>\n

17.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 Which one of the following equilibrium reactions is not<\/strong> affected by a change in pressure?<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 D<\/p>\n

18.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 What does it mean to say that a chemical reaction has reached equilibrium?<\/p>\n

19.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 The forward reaction of the equilibrium system below is endothermic. Dilute HCl is added and the colour changes to blue.\u00a0 What colour change occurs when the mixture is cooled?<\/p>\n

20.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 The reaction of nitrogen dioxide (NO2<\/sub>) forming dinitrogen tetroxide (N2<\/sub>O4<\/sub>) is exothermic in the \u00a0\u00a0\u00a0\u00a0 forward direction.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n

State two<\/strong> conditions will cause the equilibrium mixture to go dark brown?<\/p>\n

21.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 Ammonia is formed in the Haber process according to the following balanced equation.<\/p>\n

N2 <\/sub>+ 3H2<\/sub>\u00a0 \u00a02NH3<\/sub><\/p>\n

\u00a0<\/em><\/strong><\/p>\n

The table shows the percentages of ammonia present at equilibrium under different conditions of temperature T and pressure P when hydrogen and nitrogen gases were mixed in a 3:1 molar ratio. Is this an endothermic or exothermic reaction? Give a reason for your answer.<\/p>\n

22.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 The following equilibrium involves two compounds of phosphorus.<\/p>\n

PCl3(g)<\/sub>\u00a0\u00a0\u00a0 +\u00a0\u00a0 3NH3<\/sub>\u00a0(g)<\/sub>\u00a0\u00a0 \u00a0<\/em><\/strong>\u00a0\u00a0\u00a0\u00a0P(NH2<\/sub>)3(g)<\/sub>\u00a0\u00a0\u00a0 +\u00a0\u00a0 3HCl(g)<\/sub><\/p>\n

(a)\u00a0 An increase in temperature moves the equilibrium to the left. \u00a0What does this indicate about the enthalpy change for the forward reaction?\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0<\/p>\n

(b)\u00a0 What effect, if any, will an increase in pressure have on the equilibrium?<\/p>\n

23.<\/strong> \u00a0\u00a0\u00a0\u00a0 The balanced equation for a reaction at equilibrium is:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 aA + bB\u00a0 <\/strong><\/em><\/strong>\u00a0\u00a0\u00a0cC\u00a0 +\u00a0 dD<\/strong><\/p>\n

(a)\u00a0 For this reaction, the equilibrium constant, K, can be defined as:<\/p>\n

where [A] represents the concentration of A, etc and a represents the number of moles of A,etc.<\/p>\n

(i)\u00a0 Write down the expression for the equilibrium constant for the following \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0equilibrium.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 N2<\/sub>(g)\u00a0 + 3H2<\/sub>(g) <\/em><\/strong>\u00a0\u00a02NH3<\/sub>(g)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n

(ii)\u00a0 What will happen to the position of the equilibrium if the reaction is carried out over a catalyst?\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n

(b)\u00a0 In industry, the reaction of nitrogen with hydrogen to produce ammonia by the Haber Process does not attain equilibrium.<\/p>\n

Give one feature of the operating conditions which leads to the Haber Process not reaching equilibrium<\/p>\n

24.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 When a yellow solution of iron (III) chloride (FeCl3<\/sub>)and a colourless solution of potassium thiocyanate (KCNS) were mixed in a test tube, a red colour appeared and the following\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 equilibrium was established:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Fe3+<\/sup>(aq)<\/sub>\u00a0\u00a0 +\u00a0\u00a0 CNS–<\/sup>(aq) <\/sub>\u00a0 \u00a0\u00a0\u00a0\u00a0Fe(CNS)2+<\/sup>(aq)<\/sub><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 yellow\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0 red<\/p>\n

Explain:<\/p>\n

(a) the effect on the Fe3+<\/sup> ion concentration of adding KCNS to the equilibrium mixture<\/p>\n

(b) why changing the pressure has no effect on this reaction.<\/p>\n

25.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 Consider the following equilibrium reaction at room temperature used to dissolve iodine (I2<\/sub>) \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 crystals in an aqueous solution of iodide ions (I–<\/sup>).<\/p>\n

I2(aq)<\/sub>\u00a0 +\u00a0\u00a0 I –<\/sup>(aq)\u00a0 <\/sub>\u00a0I3<\/sub>–<\/sup>(aq)<\/sub><\/p>\n

State and explain the effect on the equilibrium concentration of triiodide ions of adding a substance that reacts with iodine, eg. starch.<\/p>\n

26.<\/strong> Iodine monochloride and chlorine gas react together to establish the following equilibrium in a closed system.<\/p>\n

Which line in the table shows the conditions that would cause the greatest increase in the amount of ICl3<\/sub> produced in this reaction.<\/p>\n","protected":false},"excerpt":{"rendered":"

1.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The reaction between SO2 and O2 may be described as 2SO2(g) + O2(g) \u00a02SO3(g)\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u0394H = -196 kJ mol-1 Select the two conditions that will favour a high yield of SO3. A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Removal of SO2 B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Lower the pressure C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Lower the temperature D\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Use a catalyst E\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Addition of more O2 2.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 … Continue reading “Equilibrium”<\/span><\/a><\/p>\n","protected":false},"author":2454,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-12","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages\/12","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/users\/2454"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/comments?post=12"}],"version-history":[{"count":3,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages\/12\/revisions"}],"predecessor-version":[{"id":34,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages\/12\/revisions\/34"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/media?parent=12"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}