LawLord Posted January 5, 2010 Posted January 5, 2010 (edited) The cation of an acid and the anion of a base combine to make salt. H+ + OH- ==> H2O. Does this mean water is classed as a salt? I have been trying to find a good definition of salt (clear), does anyone have one? Also can someone clarify what Hydronium is for me? Is it another name for H+ or H3O+? Wiki is confusing: http://en.wikipedia.org/wiki/Hydronium Edited January 5, 2010 by LawLord Another question
toastywombel Posted January 6, 2010 Posted January 6, 2010 The cation of an acid and the anion of a base combine to make salt. H+ + OH- ==> H2O. Does this mean water is classed as a salt? I have been trying to find a good definition of salt (clear), does anyone have one? Also can someone clarify what Hydronium is for me? Is it another name for H+ or H3O+? Wiki is confusing:http://en.wikipedia.org/wiki/Hydronium Salt: A chemical compound formed by replacing all or part of the hydrogen ions of an acid with metal ions or electropositive radicals. (3) So no oxygen is not a metal ion, nor is oxygen an electropositive radical. (2) "In chemistry, hydronium is the common name for the aqueous cation H3O+ derived from protonation of water. It is the simplest type of an oxonium ion." (1) 1. http://www.google.com/search?hl=en&defl=en&q=define:Hydronium&ei=XtNDS_OvFYmysgP4q6CfBg&sa=X&oi=glossary_definition&ct=title&ved=0CAcQkAE 2. http://www.encyclopedia.com/doc/1O13-electropositiveelement.html 3. http://www.thefreedictionary.com/SALT
LawLord Posted January 6, 2010 Author Posted January 6, 2010 Salt: A chemical compound formed by replacing all or part of the hydrogen ions of an acid with metal ions or electropositive radicals. (3) What is an electropositive radical? [quote name="In chemistry' date=' hydronium is the common name for the aqueous cation H3O+ derived from protonation of water. It is the simplest type of an oxonium ion." (1) [/quote] I did see that, but why doesn't the O and H combine to make another OH? Giving us 2H+? What i am trying to figure out, is why do acidic salts produce hydronium instead of Hydrogen ions (acids are proton donators after all). Why is the definition of an acidic salt not "a salt that donates protons"? In second paragraph: http://en.wikipedia.org/wiki/Salt_%28chemistry%29
John Cuthber Posted January 6, 2010 Posted January 6, 2010 The ammonium ion forms salts; no metals required. Under some circumstances the hydronium ion does too, H3O+ ClO4- (perchloric acid monohydrate) for example, but (unlike perchlorate) the hydroxide ion is too strong a base to co-exist with the hydronium ion. Water isn't ionic- if it were it would conduct electriciyy a whole lot better.
LawLord Posted January 7, 2010 Author Posted January 7, 2010 ok, I understand what hydronium is now, it is just a hydrogen ion in aquerius solution. But still don't understand what an "electropositive radical" is, and therefore am still confused about what a salt is. Another question. I read in my chemistry textbook that a metal and water combine to make a metal hydroxide and Hydrogen. However, I know that adding iron to water makes iron oxide, how does this work? Does anyone know the exceptions to the above rule?
foodchain Posted January 7, 2010 Posted January 7, 2010 However, I know that adding iron to water makes iron oxide, how does this work? I am not sure if its what you are asking for but most metal/nonmetal bonds I know of are simply ionic with the metal being the electron donor. I also think this then tends to deal with electronegativity of the elements involved.
LawLord Posted January 7, 2010 Author Posted January 7, 2010 Metal + water = metal hydroxide + Hydrogen ie: Sodium + water = Sodium Hydroxide + Hydrogen Copper + water = Copper Hydroxide + Hydrogen. You see? Sodium and copper are metals and they react with water to form a their respective hydroxides. What I want to know, is what metals DON'T react this way. I'm pretty sure iron doesn't. I believe the reaction would be: 2Fe + 2H2O = 2FeO + 2H2 Sodium: 2Na + 2H2O = 2NaOH + H2
greenprogrammin Posted January 8, 2010 Posted January 8, 2010 (edited) An electropositive radical is a free electron in a shell. Typically most people think of free radicals. They are very reactive. Obviously they are capable of providing a electropositive charge on a species. Typically an electron produces a negative charge (electronegative). An electropositive radical vs. an electronegative species is something you could consider in a seperate thread (to maintain clarity). Water is not a salt. Water has covalent bonds which share electrons. An ionic bond is required to make a salt (in my definition). That is what the above definition is trying to tell you in a technical term. A radical is the free electron on the element which makes it reactive. A salt is made from a anion and a cation. Ionic bonds vs. covalent bonds are the primary issues to consider. There are also different types of covalent bonds (pi, sigma, etc...). I'm sure if you look into ionic bonds you will notice the electronegative and electropositive radical / charge interactions to make the bond. To think about the physical differences between an ionic bond think about the boiling point of salts versus any organic matter with a covalent bond. The Boiling point of salt is very high in comparrison to covalently bound molecules. Hope this puts you on the right direction. Edited January 8, 2010 by greenprogrammin
LawLord Posted January 8, 2010 Author Posted January 8, 2010 That is very helpful, thank you! I see where I went wrong, I forgot water is covalent! I learn't along time ago something along the lines of: The cation of an acid and the anion of a base combine to make (salt?). or The anion of an acid and the cation of a base combine to make salt (or something else). Does this look familier? I'm trying to work out what it is, but I only remember part of the rule...
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