Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: hnes on February 16, 2019, 09:11:25 AM
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Hi!
I have a norwegian science book for high school, and many of the assertions are confusing me. Here's one:
"In clean water the voltage between Zn and Cu is 1,1 V. Zn is negative pole. This tells us that
Zn has bigger ability than Cu to give ions to the water, and we're getting more electrons on the Zn-rod than the Cu-rod."
To get this voltage, i guess Zn has to get oxidized to Zn2+ and Cu2+ has to be reduced. But there are no Cu-ions in water, so how do they get 1,1V? Is this just rubbish?
Thanks!
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Sadly, it is plain wrong. 1.1 V needs metal electrodes to be submerged not in just water, but in 1 M solutions of Zn2+ and Cu2+.
I understand HS books need some simplifications to help students get the idea without getting into confusing details, but it should never justify writing rubbish :(
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Sadly, it is plain wrong. 1.1 V needs metal electrodes to be submerged not in just water, but in 1 M solutions of Zn2+ and Cu2+.
I understand HS books need some simplifications to help students get the idea without getting into confusing details, but it should never justify writing rubbish :(
Thanks for the reply!
I'm so sick of these over-simplified text books. I mean, it's ok to simplify, but it should be simplified in such a way that it help you get the consepts.
Take the use of lemon-battery's, for instance. Do you really learn anything from that? I mean, you learn that you need an electrolyte, kathode and anode, but that is the same thing you learn in primary school. When you use it in high school, a better elaboration of the consepts should be added. In my text book it is used to explain "the difference in voltage" between the metals. And, that is also kind of wrong.
https://surface.syr.edu/cgi/viewcontent.cgi?referer=https://en.wikipedia.org/&httpsredir=1&article=1001&context=che