物化热力学第一定律答案 下载本文

(4)

12H2?g?+12Cl2?g?=HCl?g?;?rHm??92.30 kJ?mol

??1计算反应2NaCl?s?+H2SO4?l?=Na2SO4?s?+2HCl?g?在298 K时的?rHm和?rUm。

?rHm??rHm?3??2?rHm??????4??2?rHm?1???rHm?2????55.4 kJ?mol???1

?rUm??rHm?RT?n?g???rHm?2RT??50.4 kJ?mol?1

35. 已知反应:

H2?g?+?112O2?g?=H2O?l?;?rHm12??298 K???285.9 kJ?mol?1,水的气化热为

?2.445kJ?g,计算反应:H2?g?+解

O2?g?=H2O?g?的?rHm?298 K?。

?rHm(298 K)??rHm(H2O, l)??vapHm????(?285.9?18?2.445) kJ?mol?1?1

??242 kJ?mol

36. 已知反应:

(1) C?金刚石?+O2?g?=CO2?g?;?rHm?298 K???395.4 kJ?mol

??1(2) C?石墨?+O2?g?=CO2?g?;?rHm?298 K???393.5 kJ?mol

??1求C?石墨??C?金刚石?的?trsHm?298 K?。

?解 ?trHs?m??Hr?2??m??Hr??1m??1.9 kJ?m ol?137. 利用下列数据计算HCl?g?的生成焓。

?(1) NH3?aq,???HCl?aq,???NH4Cl?aq,??;?rHm?298 K???50.21 kJ?mol?1

(2) NH3?g?+H2O=NH3?aq,??;?rHm?298 K???35.561 kJ?mol

??1(3) HCl?g?+H2O=HCl?aq,??;?rHm?298 K???73.22 kJ?mol

??1(4) NH4Cl?s?+H2O=NH4Cl?aq,??;?rHm?298 K???16.32 kJ?mol

??1(5) (6) 解

1212N2?g?+2H2?g?+N2?g?+3212Cl2?g?=NH4Cl?s?;?rHm???298 K???313.8 kJ?mol?1

?1H2?g?=NH3?g?;?rHm?298 K???46.02 kJ?mol

?fHm?HCl,g???rHm?5???rHm?4???rHm?6???????rHm?1???rHm?2???rHm?3?

?????92.5 kJ?mol?138. 利用标准摩尔生成焓数据,计算下列反应的?rHm?298 K?。

?(1) Cl2?g?+2KI?s?=2KCl?s?+I2?s? (2) CO?g?+H2O?g?=CO2?g?+H2?g? (3) SO2?g?+12O2?g?+H2O?l?=H2SO4?l?

(4) CaCO3?s?=CaO?s?+CO2?g?

(5) CaO?s?+3C?石墨?=CaC2?s?+CO?g? (6) Fe2O3?s?+CO?g?=CO2?g?+2FeO?s? (7) 2H2S?g?+SO2?g?=3S?s?+2H2O?g? (8) 2Fe2O3?s?+3C?石墨?=4Fe?s?+3CO2?g? 解

(1) ?rHm(298 K)?2?fHm[KCl(s)]?2?fHm[KI(s)] ?[2?(?436.747)?2?(?327.9)] kJ?mol ??217.694 kJ?mol??1?1??

(2) ?rHm(298 K)??fHm[CO2(g)]??fHm[CO(g)]??fHm[H2O(g)] ?[?393.509?(?110.525)?(?241.818)] kJ?mol ??41.166 kJ?mol??1?1??

(3) ?rHm(298 K)??fHm[H2SO4(l)]??fHm[H2O(l)]??fHm[SO2(l)] ?[?813.989?(?285.83)?(?296.83)] kJ?mol ??231.329 kJ?mol????1

?1(4) ?rHm(298 K)??fHm[CaO(s)]??fHm[CO2(g)]??fHm[CaCO3(s)] ?[?635.09?(?393.51)?(?1206.87)] kJ?mol ?178.27 kJ?mol?1?1??

(5) ?rHm(298 K)??fHm[CaC2(s)]??fHm[CO(g)]??fHm[CaO(s)] ?[?59.8?(?110.525)?(?635.09)] kJ?mol ?464.765 kJ?mol?????1

?1(6) ?rHm(298 K)?2??fHm[FeO(s)]??fHm[CO2(g)]??fHm[Fe2O3(s)]??fHm[CO(g)] ?[2?(?272)?(?393.509)?(?110.525)?(?824.2)] kJ?mol ?2.784 kJ?mol?1?1???(7) ?rHm(298 K)?2??fHm[H2O(g)]?3??fHm[S(s)]??fHm[SO2(g)]?2??fHm[H2S(g)] ?[2?(?241.818)?(?296.83)?2?(?20.63)] kJ?mol ??166.176 kJ?mol??1?1????(8) ?rHm(298 K)?3??fHm[CO2(g)]?2??fHm[Fe2O3(s)] ?[3?(?393.509)?2?(?824.2)] kJ?mol ??467.873 kJ?mol?1?1?

39. 利用附录中的数据,计算下列反应的?rHm?298 K?。

?(1) C2H4?g?+H2?g?=C2H6?g? (2) 3C2H2?g?=C6H6?l? (3) C4H10?g?=C4H8?g?+H2?g? (4) C4H10?g?=C4H6?g?+2H2?g? 解

(1) ?rHm(298 K)??fHm[C2H6(g)]??fHm[C2H4(g)] ??84.68 kJ?mol?1???52.26 kJ?mol?1

??136.94 kJ?mol??1(2) ?rHm(298 K)??fHm(C6H6(l))?3??fHm(C2H2(g)) ?49.04 kJ?mol?1??3?(226.73 kJ?mol)

?1?1 ??631.15 kJ?mol?(3) ?rHm(298 K)??fHm[C4H8(g)]??fHm[C4H10(g)] ??0.13 kJ?mol?1??(?126.15 kJ?mol)

?1 ?126.02 kJ?mol??1(4) ?rHm(298 K)??fHm[C4H6(g)]??fHm[C4H10(g)] ?110.16 kJ?mol?1??(?134.52 kJ?mol)

?1?1 ?244.68 kJ?mol40. 已知C2H5OH?l?在25℃时的标准摩尔燃烧焓为-1367kJ?mol,试用CO2?g?和

?1H2O?l?在298 K时的生成焓,计算C2H5OH?l?在298 K时的标准摩尔生成焓。

解 查表得:

?fHm?CO2,g???393.514 kJ?mol,?fHm?H2O,l???285.84 kJ?mol。

???1?1C2H5OH?l?+3O2?g?=2CO2?g?+3H2O?l?

?cHm?C2H5OH,l??2?fHm?CO2,g??3?fHm?H2O,l???fHm?C2H5OH,l?

?????fHm?C2H5OH,l??2?fHm?CO2,g??3?fHm?H2O,l???cHm?C2H5OH,l???????275.4 kJ?mol?1

Pb?s?、41. 已知PbO?s?在291 K的摩尔生成焓为-219.5kJ?mol,在291 K至473 K之间,

?10.900和0.218J?gO2?g?及PbO?s?的平均热容各为0.134、473 K时的摩尔生成焓。 解 Pb?s?+??1?K?1,试计算PbO?s?在

12O2?g?=PbO?s?

??fHm?T2???fHm?T1???Cp?T2?T1?????219.5??0.218?223?0.134?207??12?0.9?32??10?1?3?182? kJ?mol

?1??218 kJ?mol42. 已知反应CO2?g??C?石墨??2CO?g?,在

?5?1293 K

?时的反应焓

?rHm?293 K???1.732?10kJ?mol,求该反应的?rHm?f?T?的关系式。所需

热容数据自行查表。 解 查得:

Cp,m?CO2,g???28.66?35.702?10?3TK?J?K?1?mol?1

?35Cp,m?C,石墨???17.15?4.27?10TK?8.79?10?KT??2?J?K?1?mol?1 ??35Cp,m?CO,g???26.5366?7.6831?10TK?0.46?10?KT??2?J?K?1?mol?1 ??Cp,m?2Cp,m?CO,g??Cp,m?石墨??Cp,m?CO2,g??35??7.2632?24.6058?10TK?7.87?10?KT??2?J?K?1?mol?1?

?rHm?T???rHm?293 K????5? T 293 K?CpdT??1.748?10?7.26TK?12.30?10?3

?1?TK??7.87?10KT?J?K52?mol?143. 已知H2?g?+I2?s?=2HI?g?在291 K时的?rHm?49.45 kJ?mol;I2?s?的熔点是

??1386.5 K,其熔化焓为1.674?10J?mol;I2?l?的沸点是457.3 K,其气化焓为

4.268?10J?mol4?14-1; I2?s?、62.67、I2?l?及I2?g?的平均摩尔定压热容分别为55.65、

36.86J?K?1?mol?1。试计算反应H2?g?+I2?s?=2HI?g?在473 K时的反应焓。(其他

所需数据可查附表。) 解 查得:

CC?rHm?p,m?H2,g??28.84 J?K?1?mol?1?HI,g??29.16 J?K?1p,m?molp,m?1

?473 K????rHm?291 K???2C???HI??Cp,m?H2????T1??Cp,mCI,sT?T2?T1????p,m?2??fCp,m?I2,l??Tb?Tf??

?I2,g???T2?Tb???fusHm4?1??vapHm????1.49?10J?K?mol?144. 298 K时,甲烷的燃烧焓为-890.4kJ?mol,液态水的气化焓为44.02kJ?mol。设空

气中氧气与氮气的物质的量之比是1:4,试计算甲烷与理论量的空气混合燃烧时所能达到的最高温度(所需热容数据自行查找;计算时,假设燃烧所放出的热全部用于提高产物的温度,不考虑产物的解离)

解CH4g?+2O2?g?=CO2?g?+2H2O?l? ?rHm?298 K???890.4 kJ?mol

??1?1?1H2O?l?=H2O?g? ?vapHm?44.02 kJ?mol

??1所以 CH4?g?+2O2?g?=CO2?g?+2H2O?g?

?rHm?298 K???802.4 kJ?mol

??1热全部用来提高产物的温度,??rHm?298 K???H?升温?。

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