[cliverlong]

Hi,

  I have read that the equivalent weight of an element (I'm in historic mode this evening) is that weight of an element that either combines with or displaces (approximately)

1g Hydrogen
8g Oxygen

So .

If I consider

H₂ + CuO --> H₂O + Cu

I can apply knowledge of atomic weights (masses) to come up with

2g + 79.5g --> 18g + 63.5g

but I can't seem to make the connection to understand how to apply equivalent weights to this situation (leaving aside I have had to assume I know that hydrogen is a diatomic molecule - and that the element copper is a product rather than a reactant in my example).

Is there a simpler example I can consider? I'm looking for an example that relates to a practical, relatively "easy" to perform experiment. I did think about just combining hydrogen and oxygen, but in that case one would probably be measuring gas volumes rather than gas weights - and the interpretation of the results would then have to assume Gay-Lussac's (??) law of gases.

I suppose I'm looking for a couple of worked examples of equivalent weights which as well as showing how the numbers work also give a little on how the experiment would be conducted - rather than just an exercise in number manipulation. The references to "equivalent weight" that Google comes up with are just statements of the (various) definitions of equivalent weight not descriptions of how to apply or use it.

I recognise that atomic weight / valency = equiv weight ; and if that is ignored, we end up with a formula of HO for water.

I know equivalent weights are "old fashioned" but I'm trying to grasp how analytical chemistry was performed before the atomic theory.

Are equivalent weights used at all in modern chemistry?


Thanks

Clive

[Mitch]

What are you asking for specifically? An experiment you can do to test this theory?

[cliverlong]

What are you asking for specifically?

. I'm looking for a couple of worked examples of equivalent weights which as well as showing how the numbers work (i.e. what to measure and what to calculate and how to make deductions from the calculations). I would like the examples to give a little information on how the experiment would be conducted  . The links to "equivalent weight" that Google lists are just statements of the (various) definitions of equivalent weight not descriptions of how to apply or use it or deduce something about equivalent weights for that particular reaction/experiement.

An experiment you can do to test this theory?

Yes and how to analyse the results.

Clive