作者onlyveritas ( 食梦者)
看板Chemistry
标题[问题] 无机固体及酸硷问题
时间Thu Nov 28 08:52:31 2013
1.For which of the following pairs indicate which substance is expected to be:
(a)More covalent ZnO or ZnS
参考答案:
ZnS
硫离子半径较大，造成阴阳离子尺寸较接近，应该more ionic才对吧？奇怪？
2.By extrapolation from known data for Cr, W, and Mo, Seaborg estimated the
following emf values for the couples involving
-0.5 -0.2 -0.7 0.0
Ea。 MO3 → M2O5 → MO2 → M3+ → M
Predict the results of the following.
(a)M is placed in 1M HCl.
(b)MCl3 is placed in an acidic solution containing FeSO4.
(c)MO2 and MO3 are in contact in acidic solution.
(d)M3+ and MO3 are in contact in acidic soultion.
(e)M is treated with excess concentrated HNO3
参考答案:
(a)No reaction occurs. E。=0.0 for the evolution of H2 with the
formation of M3+ , therefore, overvoltage effects would be
sufficient to prevent this reaction.
(b)2M+ +3H2O+SO2-→2MO2+H2SO3+4H+ E。=0.87V
(c)No recation.(E。=-0.3 for MO2+MO3→M2O5)
(d)2M3+ +MO3+3H2O→3MO2+6H+ E。=0.35V
(e)M+2MHNO3→MO3+2NO+H2O E。=0.72V
我的疑问是(b)~(e)的电位是如何计算出来的？用 Nerst equation吗？可是没有给离子
浓度？谢谢。
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