第三十四章標(biāo)準(zhǔn)燃燒中和溶解和生成焓變課堂練習(xí)A341熱能變化

第三十四章標(biāo)準(zhǔn)燃燒、中和、溶解和生成焓變課堂練習(xí)A34.1熱能變化=137111.5kJ=342.75kJ21.0612.016.0因此，共釋放342.75kJ熱能。A34.2(a)假設(shè)Y是混雜物中氫的質(zhì)量。Y50Y890.4=47251.02285.8+1.012.04Y=22.3因此，氫和甲烷的質(zhì)量分別是22.3g和27.7g。假設(shè)X是混雜物中氫的質(zhì)量。X50X890.4=50001.02285.8+1.012.04X=25.4因此，混雜物中氫的質(zhì)量百分比25.4100%5050.8%(a)CH3CH2COOHNH3CH3CH2COOH的電離作用所需熱能49.9(57.1)kJmol1=7.2kJmol1NH3的電離作用所需熱能52.2(57.1)kJmol1=4.9kJmol1CH3CH2COOH和NH3的中和焓變Hneut估計(jì)值11A34.31.(a)H=92.31=12kJmol184.6kJmol(b)H=238.62kJmol11=477.2kJmol1H=+1.9kJmol(d)H=110.52+(393.5)kJmol1=614.5kJmol12.(a)C8H18(l)+81O2(g)8CO2(g)+9H2O(l)2Hc=5512kJmol1(b)CH3COOH(aq)+NH3(aq)CH3COONH4(aq)Hneut=51.5kJmol1(c)KBr(s)+aqK+(aq)+Br(aq)Hsoln=+20.0kJmol1(d)2B(s)+3H2(g)B2H6(g)1A34.4轉(zhuǎn)移至水的熱能=mwc(T2T1)=(500)(1)g4.2Jg1K1[(50.1+273)(25.3+273)]K=52080J燃燒了的甲醇的摩爾數(shù)=2.65g=0.0828mol416.0gmol112.01.0燃燒每一摩爾的甲醇所釋出的熱能52080J-11==62900Jmol=629kJmol0.0828mol因此，甲醇的燃燒焓變是629kJmol1。A34.5轉(zhuǎn)移至溶液的熱能=mc(T2T1)=(75.0+50.0)(1)g4.2Jg1K1[(27.0+273)(25.0+273)]K=1050J所形成的水之摩爾數(shù)350.03=0.5moldmdm0.025mol(氫氧化鈉是限量反應(yīng)物。)Hneut=1050Jmol1=42000Jmol1=42kJmol10.025A34.61.轉(zhuǎn)移至溶液的熱能=mc(T2T1)=45.0g4.2Jg1K14.8K=907.2JHsoln=907.2Jmol11.066.935.5=36288Jmol1(36.3kJmol1)2.(a)轉(zhuǎn)移至溶液的熱能=mc(T2T1)=(50)(1)g4.2Jg1K13.89K=816.9J已溶的HCl質(zhì)量=10gmin110min=1.67g60已溶的HCl摩爾數(shù)=1.67mol=0.0458mol135.5每摩爾已溶的HCl所釋出的熱能=816.9J=17836Jmol10.0458mol因此，氯化氫的溶解焓變是17836Jmol1.確保溶液已經(jīng)過無限稀釋。第三十四章標(biāo)準(zhǔn)燃燒、中和、溶解和生成焓變單元練習(xí)1；101325；298；濃度摩爾燃燒中和溶解；熱量；無限稀釋生成；標(biāo)準(zhǔn)態(tài)；物質(zhì)熱能；流失；標(biāo)準(zhǔn)狀況彈式熱能；比熱容；標(biāo)準(zhǔn)狀況ABDCBC(a)斷裂氧化鋁中的強(qiáng)離子鍵需要耗資能量。(b)2Al(s)+11O2(g)Al2O3(s)2(c)3350kJmol1=1675kJmol12(d)2Al(s)+11O2(g)Al2O3(s)Hf=1675kJmol1217.(a)所需能量=mcT=400cm31gcm34.2Jg1K1[(70+273)(20+273)]K=84000J(84kJ)所需的丙-1-醇的摩爾數(shù)=84mol=0.0418mol所需的丙-1-醇的質(zhì)量2010=0.0418(12.03+1.08+16.0)g=2.51g需要較大質(zhì)量。加熱時(shí)有熱能對外流失。18.(a)HSO(aq)+2KOH(aq)KSO(aq)+2HO(l)24242(b)標(biāo)準(zhǔn)中和焓變是指在標(biāo)準(zhǔn)狀況下，酸和鹼互相中和，生成1摩爾的水時(shí)的焓變。(c)1H2SO4(aq)+KOH(aq)1K2SO4(aq)+H2O(l)22(d)2465.00已反應(yīng)的HSO(aq)的摩爾數(shù)=0.50mol=0.0325mol1000已反應(yīng)的KOH(aq)的摩爾數(shù)=0.9050.00mol=0.0450mol1000從方程式可見，1摩爾H2SO4(aq)需要2摩爾KOH(aq)來完好中和，所以0.0325摩爾H2SO4(aq)需要0.0650摩爾KOH(aq)來完好中和，因此KOH是限量反應(yīng)物。中和作用釋出的能量=mcT=(65.00+50.00)cm31.0gcm34.2Jg1K1[(30.3+273)(25.0+273)]K2560J(2.56kJ)硫酸和氫氧化鉀的中和作用之標(biāo)準(zhǔn)焓變=

2.56

kJmol

1=

56.9kJmol

10.0450(a)放熱的。水吸