E>2aEB.1aE<2aEC.1aE=2aED.不能确定1.不用查表,将下列物质按其标准熵)K15.298(?mS值由大到小的顺序排列,并简单说明理由。(1))s(K;(2))s(Na;(3))l(Br2;(4))g(Br2;(5))s(KCl。解:(4))g(Br2(3))l(Br2(5))s(KCl(1))s(K(2))s(Na理由:一般(相对分子质量相近时)气态的大于液态的;液体的大于固体物质的;而当温度和聚集态相同时,分子或晶体结构较复杂的物质的熵大,原子序数大的大于小的。2.分析下列反应的熵值是增加还是减少,并说明理由。(1))s(I2???)g(I2;(2)O(l)H2???)g(O21)g(H22?;(3))g(O)g(CO22????)g(CO22;(4))g(B)s(A22????)g(AB2。解:(1)增加:气态大于固态(2)增加:气态大于液态(3)减少:气体分子数减少(4)增加:气体分子数增多3.试用书末附录3中的标准热力学数据,计算下列反应的)K15.298(??mrS和)K15.298(??mrG。(1)O(l)4HFe(s)32?===)g(H4)s(OFe243?;(2))aq(H2)s(Zn??===)g(H)aq(Zn22??;(3)O(l)H)s(CaO2?===)aq(OH2)aq(Ca2???;(4)AgBr(s)===)l(Br21)s(Ag?。解:)15.298()15.298(,KSKSBmBBmr??????)15.298()15.298(,KGKGBmfBBmr???????(1))K15.298(??mrS=307.711KmolJ????)K15.298(??mfG=-66.91molkJ??(2))K15.298(??mrS=-23.011KmolJ????)K15.298(??mfG=-147.061molkJ??
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