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研究生入学考试物理化学模拟试卷(二)参考答案

一、单项选择题

1.(D) 2. (C) 3. (A) 4. (C) 5. (B) 6. (C) 7. (B) 8. (C) 9. (B) 10. (C) 11. (C) 12. (C) 13. (C)

14. (B) 15. (D) 16. (B) 17. (B) 18. (B) 19. (D) 20. (B) 二、简答题答案略

三、解 (1)该过程为不可逆相变过程,设计如下过程

θG、?A、?S、?H、?U C6H6?l,p1?pθ??????????C6H6(g,p2?0.9p)

?G1?0?A1,?H1 ?G2,?H2?0

?A2

C6H6(g,p)

?G??G1??G2?0?RTlnp20.9??-1-1??8.314?353.3ln?J?mol=-309.3J?mol p1?1??A??A1??A2

?A1??G1?p?V??pVg??RT???8.314?353.3?J?mol=-2937J?mol ?A2??G2???pV???309.3J?mol

-1θ-1-1?A??A1??A2???2937+(-309.3)?J?mol=-3246.3J?mol

-1-1?H=?H1??H2?30.75kJ?mol

-1?S??H??GT?30.75?103?(?309.3)?-1-1-1-1???J?K?mol?87.91J?K?mol

353.3???U??H???pV???H?p2Vg??H?RT

??30.75?8.314?353.3?10?3?kJ?mol-1=27.81kJ?mol

-1四、解 20℃时,HCl在苯中的亨利系数

M(HCl)=36.5,M(苯)=78

p(HCl)x(HCl)101.3250.0425k=?kPa?2384kPa

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当HCl和笨蒸气的总压p为101.325kPa时,

p?p??HCl?pC6H6?kxHCl?pxC6H6?kxHCl?p(1?xHCl)

则 xp?p?101.32?5HCl?k?p??2384?10?100.038 5WHCl由 x36.5HCl?W?0.038 5HCl10036.5?78求得 W0.0385?100/78HCl????36.5??1?0.0385?g=1.87g

?五、 解 反应 BaCO3(s)→BaO(s)+CO2(g)

?θθθθrHm (298.15K)= ?fHm (BaO,s)+ ?fHm (CO2,g)﹣?fHm (BaCO3,s)

={(﹣393.51﹣556.47)﹣(﹣1217.5)}kJ·mol-1

=267.52 kJ·mol-1

?Gθθθθrm (298.15K)= ?fGm (BaO,s)+ ?fGm (CO2,g)﹣?fGm (BaCO3,s)

={(﹣394.38﹣527.18) ﹣(﹣1138.0)} kJ·mol-1 =216.44 kJ·mol-1

△rCp,m=Cp,m(BaO,s) +Cp,m(CO2,g)﹣Cp,m(BaCO3,s)

={37.66+43.51﹣90.79} J·K-1·mol-1

=﹣9.62 J·K-1·mol-1

由基尔霍夫定律(??HdT)??Cp ,不定积分得

?H??H0??rCpT (1)

T=298.15K, ?θrHm (298.15K)代入上式,可得

?H0?270.39kJ?mol-1

将?H0、?rCp代入式(1),可得

?θ?3rHm(T)/kJ·mol-1?270.39?9.62?10T/K

六、证明 (1)dU?TdS?pdV

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??U???T??S????p?p??V????p?T?T??VT???T?? V? 由pV?RT??,则p

p?RTRV??,??p????T?? ?VV??所以,??U???T(R)?p??V??TV???p?p?0 p2??S?p2(2)?S????V?p2??p?dp??????Tp1??T?dp ?pp2 ???RRlnp2p1pdp??p

1?Rlnp1p

2七、解 由公式 RTlncrc?2?M0?r

代入相关的数据,得 lncrc?2?0.?20.080900?0.1?10?6?0.5?8.314?298.2

lncrc?0.285,则

0crc?1.33

0八、解 对于二级反应 k1t?1c?1Ac,则

A01?? k1?11?t??11??cAcA?????1??1????mol?1?L?min?10?60??0.070.1???7.14?10?2mol?1?L?min?1

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Ea由 k?Ae?RT,

Ea,2得 k?Ea,1RT1?Ae,kRT2?Ae?

Ea,1?Ea,RT?2ln?k2??k?

?1?3代入已知数据得

10.4?6108.314?373?lnk27.14?10?2 求得 k2?2.08mol?1?L?min?1 由 k12t?1c?

BcB0代入相关数据,求得 t?22.4m in九、解(1)电池的表示式为

Pb(s)PbSO4(s)H2SO4(aq)PbSO4(s)PbO2(s)

正极反应:PbO(2s)+SO2-4(aq)+4H+(aq)+2e- ? PbSO4(s)+2H2O(l)

负极反应:Pb(s)+SO2-4(aq)?PbSO-4(s)+2e

(2)电池总反应:PbO+2-2(s)+Pb(s)+4H(aq)+2SO4(aq)?2PbSO4(s)+2H2O(l) E=Eθ?RT2Fln1(a22?Eθ?2RTlna? ?)F 1.918?82.?024?18.31?4298.29.64?8410a? ln 求得, a??0.0927 (3) ?rGm??2FE,可得

?rGm??2FE?{?2?9.64?8410?1.91??83810?}- 1kJmol??370.3kJ?mol-1

(4) ?θθrGm??2FE ?θrGm??RTlnKθ

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