作者fierybear ()
看板TransBioChem
标题Re: [普化] 80中山
时间Tue Jun 21 20:19:54 2005
※ 引述《ymme (迷)》之铭言：
: A 10.0g chunk of sodium metal (Na) is dropped into a mixture of 50.0g of water
: and 50.0g of ice at 0'C. The reaction is as follows:
: 2Na(s)+ 2H2O(l)-->2NaOH(aq)+H2(g) △H=-368KJ
: The △H(fus) of ice is 6.0 kj/mole. Assuming that the final mixture has a
: heat capacity of 4.18J/g'c, calculate the final temperature.
: 麻烦高手罗
10.0g Na 10.0/23 = 0.435mole
50.0g H2O(l) 50.0/18 = 2.78 mole
50.0g H2O(s) 50.0/18 = 2.78 mole
2Na(s)+ 2H2O(l)-->2NaOH(aq)+H2(g) △H=-368KJ
Na为限制试剂，得放热
368*0.435/2 = 80.0 KJ
2.7 mole H2O(s) △H(fus) = 6.0 kj/mole
冰溶化耗热2.78*6.0
剩余热量 80.0-2.78*6.0 = 63 KJ
heat capacity of 4.18J/g'c 总重 = 110.0g
63/(110.0*4.18) = 0.14 ℃
有请高手确认指正
话说...那麽旧的考古题哪来的??
好奇~~
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※ 编辑: fierybear 来自: 218.171.210.158 (06/21 20:20)