{"id":19,"date":"2014-10-21T09:38:46","date_gmt":"2014-10-21T09:38:46","guid":{"rendered":"http:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/bond-enthalpies\/"},"modified":"2014-10-21T09:50:07","modified_gmt":"2014-10-21T09:50:07","slug":"bond-enthalpies","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/bond-enthalpies\/","title":{"rendered":"Bond Enthalpies"},"content":{"rendered":"

1.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 In the presence of bright light, hydrogen and bromine react. One step in the reaction is shown<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 below.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 H2<\/sub>(g) <\/em><\/strong>+ <\/em><\/strong>Br(g) <\/em><\/strong>\u2192<\/em><\/strong> <\/em><\/strong>HBr(g) <\/em><\/strong>+ <\/em><\/strong>H(g)<\/em><\/strong><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The enthalpy change for this step can be represented as<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (H-H bond enthalpy) + (Br-Br bond enthalpy)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (H-H bond enthalpy) \u2212 (Br-Br bond enthalpy)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (H-H bond enthalpy) + (H-Br bond enthalpy)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 D \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (H-H bond enthalpy) \u2212 (H-Br bond enthalpy).<\/p>\n

2.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Use the information in the table to calculate the enthalpy change for the following reaction:<\/p>\n

H2(g)<\/sub> + Cl2(g)<\/sub> \u00e0 2HCl(g)<\/sub><\/p>\n\n\n\n\n\n\n
Bonds<\/td>\n\u0394H to break bond (kJ mol-1<\/sup>)<\/td>\n<\/tr>\n
H-H<\/td>\n432<\/td>\n<\/tr>\n
Cl-Cl<\/td>\n243<\/td>\n<\/tr>\n
H-Cl<\/td>\n428<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u00a0<\/p>\n

3.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Using the bond enthalpy values from your data booklet, calculate the enthalpy changes for the<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 following reactions:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (a) CH4(g)<\/sub> + 2O2(g)<\/sub> \u00e0 CO2(g)<\/sub> + 2H2<\/sub>O(g)<\/sub><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (b) C3<\/sub>H8(g)<\/sub> + 5O2(g)<\/sub> \u00e0 3CO2(g)<\/sub> + 4H2<\/sub>O(g)<\/sub><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (c) C3<\/sub>H6(g)<\/sub> + H2(g)<\/sub> \u00e0 C3<\/sub>H8(g)<\/sub><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (d) N2(g) <\/sub>+ 2O2(g)<\/sub> \u00e0 2NO2(g)<\/sub><\/p>\n

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

4.<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The production of hydrogen chloride from hydrogen and chlorine is exothermic.<\/p>\n

H2<\/sub>(g)\u00a0\u00a0 +\u00a0\u00a0 Cl2<\/sub>(g)\u00a0\u00a0\u00a0\u00a0\u00a0 \u2192\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2HCl(g)<\/p>\n

Using bond enthalpy values, calculate the enthalpy change, in kJ mol-1<\/sup>, for this reaction.\u00a0<\/p>\n

5.<\/strong> Chloromethane can be produced by the reaction of methane with chlorine.<\/p>\n

CH4<\/sub>(g) + Cl2<\/sub>(g) \u2192 CH3<\/sub>Cl(g) + HCl(g)<\/p>\n

Using bond enthalpies from the data booklet, calculate the enthalpy change, in<\/p>\n

kJ mol\u22121<\/sup>, for this reaction.<\/p>\n","protected":false},"excerpt":{"rendered":"

1.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 In the presence of bright light, hydrogen and bromine react. One step in the reaction is shown \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 below. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 H2(g) + Br(g) \u2192 HBr(g) + H(g) \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The enthalpy change for this step can be represented as \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (H-H bond enthalpy) + (Br-Br bond enthalpy) \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (H-H bond enthalpy) \u2212 … Continue reading “Bond Enthalpies”<\/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-19","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages\/19","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=19"}],"version-history":[{"count":1,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages\/19\/revisions"}],"predecessor-version":[{"id":46,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/pages\/19\/revisions\/46"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu3hwrk\/wp-json\/wp\/v2\/media?parent=19"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}