enthalpy change of displacement reaction

kintatw

2007-11-29 8:18 am

假設excess Cu+加落知道volume同concentration的Ag^+
放左X咁多 kJ

Cu+ + 2Ag^---->Cu^2+ +2Ag
咁enthalpy change係點計?

咁計岩唔岩
enthaply change=-2(X)/no. of mole of Ag^+
但係我唔明點解要乘個ENERGY 係2

更新1:

Cu+ + 2Ag^+ ---- Cu^2+ +2Ag

更新2:

回答者：不願透露自己姓名的無名氏一個唔明我問咩咁..

回答 (1)

不願透露自己姓名的無名氏一個

2007-12-01 7:45 pm

✔ 最佳答案

Most likely the question would provide you enough information about other enthalpy.

For example,
Find the enthalpy change of FORMATION with the eqt
Cu(s) + 2Ag+(aq) ---> Cu2+(aq) + 2Ag(s)

Given
Cu(s) ---> Cu2+(aq) + 2e- △H=+1
Ag(s) ---> Ag+(aq) + e- △H=+2

enthalpy change should be calculated in this way:
Ag+(aq) + e- ---> Ag(s) △H=-2
∴ 2Ag+(aq) + 2e- ---> 2Ag(s) △H=-4

+1+(-4)=-3

∴ enthalpy change of FORMATION of Cu(s) + 2Ag+(aq) ---> Cu2+(aq) + 2Ag(s)
=-3 kJ/mol

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