{"id":1035,"date":"2019-02-17T07:10:10","date_gmt":"2019-02-17T07:10:10","guid":{"rendered":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/?page_id=1035"},"modified":"2019-10-04T12:47:03","modified_gmt":"2019-10-04T12:47:03","slug":"marking-guide-unit-3h1-equilibrium","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/marking-guide-unit-3h1-equilibrium\/","title":{"rendered":"MARKING GUIDE: Unit 3H1 \u2013 Equilibrium"},"content":{"rendered":"\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
1.<\/td>\n\u00a0B<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
2.<\/td>\n\u00a0A<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
3.<\/td>\n\u00a0C<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
4.<\/td>\n\u00a0C<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
5.<\/td>\n\u00a0C<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
6.<\/td>\n\u00a0C<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
7.<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0a) i)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0ii)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0Filtration<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0iii)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0Neutralisation<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0b)i)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0hydrogen chloride<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0ii)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0Hydrogen chloride shifts the equilibrium position to the left.<\/td>\n<\/td>\n<\/tr>\n
\u00a08.<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0a)i)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0It is endothermic<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0ii)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0A decrease in pressure will cause an increase in the proportion of synthesis gas [or vice versa] (1).\u00a0 According to Le Chatelier’s Principle, when at equilibrium, a closed system will shift the position of the equilibrium to undo any change imposed.\u00a0 As there are more moles of gas on the right hand side, decreasing pressure will shift the equilibrium to the right. (1)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0iii)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0It will be increased<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0iv)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\nNo change<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
9.<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0a)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0increased<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0b)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0no change<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0c)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0decreased<\/td>\n<\/td>\n<\/tr>\n
\u00a010.<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0a)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0Natural gas<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0b)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0Sulfur dioxide may be produced causing acid rain pollution.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0d)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0According to Le Chatelier’s, the increase in pressure will cause the equilibrium to establish to the right (1), increasing the yield of methanol(1)<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
11.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\"\"<\/td>\n<\/tr>\n
12.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
\u00a013.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0a)<\/td>\n<\/tr>\n
<\/td>\n\u00a0Circle OXYGEN and NITROGEN<\/td>\n<\/tr>\n
<\/td>\n\u00a0b)<\/td>\n<\/tr>\n
<\/td>\n\u00a0Both processes are endothermic (1), According to Le Chatelier’s principle, the higher temperature will favour the endothermic\/ reverse reaction (1).<\/td>\n<\/tr>\n
<\/td>\n\u00a0c)<\/td>\n<\/tr>\n
<\/td>\n\u00a0Contact Process:\u00a0<\/strong><\/td>\n<\/tr>\n
<\/td>\nThere are 3 molecules of gas on the left-hand side of the equation, but only 2 on the right.According to Le Chatelier’s Principle, if you increase the pressure the system will respond by favouring the reaction which produces fewer molecules. [That will cause the pressure to fall again.]<\/p>\n

In order to get as much sulphur trioxide as possible in the equilibrium mixture, you need as high a pressure as possible. High pressures also increase the rate of the reaction [gas reactants closer together]. However, the reaction is done at pressures close to atmospheric pressure!<\/p>\n

BUT<\/i><\/b><\/strong><\/p>\n

At atmospheric pressure,\u00a0there is already a 99.5% conversion of sulphur dioxide into sulphur trioxide.<\/p>\n

The reason for atmospheric pressure is a cost benefit consideration.\u00a0 The very small improvement that you could achieve by increasing the pressure isn’t worth the expense of producing those high pressures.<\/td>\n<\/tr>\n

<\/td>\n\u00a0Haber Process:<\/strong><\/td>\n<\/tr>\n
<\/td>\nAccording to Le Chatelier’s Principle, if you increase the pressure the system will respond by favouring the reaction which produces fewer molecules. [That will cause the pressure to fall again.]<\/p>\n

In order to get as much ammonia as possible in the equilibrium mixture, you need as high a pressure as possible.\u00a0 In addition, the higher the pressure the better in terms of the rate of a gas reaction [gas reactants closer together].<\/p>\n

BUT<\/i><\/b><\/p>\n

Strong pipes and vessels to withstand the very high pressure are expensive to build.<\/p>\n

Energy used in pressuring and maintaining the pressure increase the running costs of the plant.<\/p>\n

A compromise between these conflicting consideration is found<\/i><\/b><\/p>\n

400 atmospheres (200 -450) is a compromise pressure chosen on economic grounds. If the pressure used is too high, the cost of generating it exceeds the price you can get for the extra ammonia produced.<\/td>\n<\/tr>\n

<\/td>\n<\/td>\n<\/tr>\n
\u00a014.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
\u00a015.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
<\/td>\nAnswer:\u00a0 The equilibrium is shifted to the right, increasing the concentraion of the hypochlorite ion.<\/p>\n

Explanation:\u00a0 [The greater the concentration of the hypoclorite ion, the greater the bleaching efficiency.\u00a0 Adding NaOH cause a neutralisation to occur, removing hydrogen ions from the equilibrium reaction.\u00a0 This will cause, by Le Chatelier’s principle,\u00a0 the equilibrium to shift to the right to undo the change, increasing the concentration of the hypochlorite ion. ]<\/td>\n<\/tr>\n

\u00a016.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
\u00a017.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
\u00a0i)<\/td>\n\u00a0EXOTHERMIC<\/td>\n<\/tr>\n
ii)<\/td>\n\u00a0No Change<\/td>\n<\/tr>\n
\u00a018.<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
<\/td>\n\u00a0The forward reaction is exothermic.\u00a0 If cooled, the equilibrium position will shift\u00a0 to undo the change (Le Chatelier’s Principle), so generates heat, by increasing the rate of the forward reaction (exothermic), shifting the equilibrium to the right, and increasing the production of methane<\/td>\n<\/tr>\n
<\/td>\n\u00a0On cooling, to below 100C, the water condenses, changing from gas to liquid, and so creates fewer moles of gas on the product side.\u00a0 The equilibrium position will shift to undo that change (Le Chatelier’s Principle), by increasing the moles of gas on the product side, increasing the production of methane<\/td>\n<\/tr>\n
\u00a019.<\/td>\n<\/td>\n<\/tr>\n
\u00a0a)<\/td>\n\u00a0Rates of forward and reverse reactions are equal.<\/td>\n<\/tr>\n
\u00a0b)<\/td>\n\u00a0Iodine will move from the chloroform partition into the KI partition.<\/td>\n<\/tr>\n
\u00a0c)<\/td>\n\u00a030gl-1<\/sup><\/td>\n<\/tr>\n
\u00a020.<\/td>\n<\/td>\n<\/tr>\n
\u00a0i)<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n\u00a0\"\"<\/td>\n<\/tr>\n
ii)<\/td>\n\u00a0Remain unchanged<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

1. \u00a0B 2. \u00a0A 3. \u00a0C 4. \u00a0C 5. \u00a0C 6. \u00a0C 7. \u00a0a) i) \u00a0 \u00a0ii) \u00a0Filtration \u00a0iii) \u00a0Neutralisation \u00a0b)i) \u00a0hydrogen chloride \u00a0ii) \u00a0Hydrogen chloride shifts the equilibrium position to the left. \u00a08. \u00a0a)i) \u00a0It is endothermic \u00a0ii) \u00a0A decrease in pressure will cause an increase in the proportion of synthesis gas [or vice … Continue reading “MARKING GUIDE: Unit 3H1 \u2013 Equilibrium”<\/span><\/a><\/p>\n","protected":false},"author":2454,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1035","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/pages\/1035","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/users\/2454"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/comments?post=1035"}],"version-history":[{"count":16,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/pages\/1035\/revisions"}],"predecessor-version":[{"id":1680,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/pages\/1035\/revisions\/1680"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hchemanswers\/wp-json\/wp\/v2\/media?parent=1035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}