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An early technique in photography involved soaking paper in firstly, a solution of common salt (sodium chloride) and then in a solution of silver nitrate. These chemicals reacted with one another to deposit crystals of silver chloride in the fibres of the paper. When this paper was exposed to light, the silver chloride became very fine dark particles of silver. This was effectively, an early form of negative and "prints" could be made from it.
Silver jewellery is normally of a type called sterling silver. This is a metal alloy which is made up of 92.5% pure silver alloyed with usually 7.5% copper.
Silver jewellery is normally of a type called sterling silver. This is a metal alloy which is made up of 92.5% pure silver alloyed with usually 7.5% copper.
shammydodger:
Dr Hungry no doubt thanked me for citing two typical uses for silver as a catalyst, which clearly he/she could not recall whilst reading a post that he/she did not place himself/herself. I fail to see the difficulty in comprehending this.
Is it not feasible that a reader of a post can thank someone for enlightening them? Since when has it been the sole prerogative of the original poster on AB to thank someone for enlightening them?
With regard to your comments about 1,2-epoxyethane, it is clear that you not entirely familiar with modern IUPAC terminology rules and the "Blue Book".
I referred to ethylene oxide in this manner as this is the correct and formal method of referring to this cyclic ether using IUPAC convention. It is immaterial whether or not the molecular formula CH2OCH2 displays structural isomerism or not, the rules stipulate that the positional structure must be disclosed in order to prevent ambiguity.
From a practical perspective, there are other reasons as well. I suggest you try looking for this epoxide in Sigma-Aldrich as ethylene oxide. Then try looking for it as 1,2-epoxyethane. Do you notice anything? Likewise, look for another ether called ethylene glycol diethyl ether and then look for 1,2-diethoxyethane. What are your conclusions?
Try looking up epoxyethane (sic) or ethylene oxide on Beilstein. How readily does Beilstein recognise these synonyms relative to 1,2-epoxyethane?
When did you last see a cylinder or container of this gas/liquid labelled "epoxyethane" as opposed to 1,2-epoxyethane?
Chemical nomenclature is an exact science immersed in pedantry. Regardless of whether or not we are appreciative of its formal aspects and this pedantry, we have to abide by the rules.
Mine's a pint! I am well aware of IUPAC, having a degree in chemistry, but I've never been given a convincing explanantion of why ethylene oxide needs to have the 1,2 in front of the epoxyethane for the IUPAC name. I can't see the scope for any ambiguity.
And don't take any of my answers as a personal attack.
:)
I'm pleased to see that you have a degree in chemistry and can appreciate the arguments I put forward - I know that sometimes I can get too technical here.
As far as ethylene oxide goes, I think its nothing more than a desire for conformity to call it 1,2-epoxyethane in line with the IUPAC rules, when it might just as well be called epoxyethane. Personally, I can�t recall anyone discussing it as 1,2-epoxyethane in conversation and I find it quite acceptable to refer to it as epoxyethane.
Where we do need these numbered prefixes is in compounds such as dichloropropane, where four positional isomers exist, each with different properties. In such compounds, these prefixes helped abolish much of the old system of sec, tert etc (Personally, the butyl alcohols were always a bugbear with me)
All the same on a daily basis, I must admit, I rarely hear anyone discussing an organic chemical by its IUPAC name as the trivial names are often less confusing. No one speaks of ethoxyethane or propan-2-ol when the listener is more familiar with diethyl ether and isopropyl alcohol despite the IUPAC names being endemic from textbooks to labels on containers as I implied above.
I've lost count of the number of times I've walked past a container of ethanoic acid when I've been looking for acetic acid.
Please be assured that I've not taken your comments personally - everyone's entitled to their opinion after all!
As far as ethylene oxide goes, I think its nothing more than a desire for conformity to call it 1,2-epoxyethane in line with the IUPAC rules, when it might just as well be called epoxyethane. Personally, I can�t recall anyone discussing it as 1,2-epoxyethane in conversation and I find it quite acceptable to refer to it as epoxyethane.
Where we do need these numbered prefixes is in compounds such as dichloropropane, where four positional isomers exist, each with different properties. In such compounds, these prefixes helped abolish much of the old system of sec, tert etc (Personally, the butyl alcohols were always a bugbear with me)
All the same on a daily basis, I must admit, I rarely hear anyone discussing an organic chemical by its IUPAC name as the trivial names are often less confusing. No one speaks of ethoxyethane or propan-2-ol when the listener is more familiar with diethyl ether and isopropyl alcohol despite the IUPAC names being endemic from textbooks to labels on containers as I implied above.
I've lost count of the number of times I've walked past a container of ethanoic acid when I've been looking for acetic acid.
Please be assured that I've not taken your comments personally - everyone's entitled to their opinion after all!
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