amphoteric? (1 Viewer)

[renaethebest]

can someone please define what an amphoteric substance is? i understand it has something to do with oxides of metals?
help would be most appreciated.

 

[Nakashima]

An amphoteric substance react with both acids and bases to form salt and water (i.e. It can act as both acid and base).

An amphiprotic substance is one that is able to both donate and accept protons, and since acids are proton donors and bases are proton acceptors, it can act both as acid and base.

The two terms are very similar - the only difference is the property of being amphiprotic doesn't limit it to acid-base reactions. It implies to all proton-transfer reactions.

And you only need to know amphiprotic for the HSC.

 

[phil2010]

can someone please define what an amphoteric substance is? i understand it has something to do with oxides of metals?
help would be most appreciated.

Amphoteric (is NOT in the syllabus) - it means that that substance REACTS with both acids and bases. (Remember that just by reacting with an acid does NOT mean it is a base eg magnesium ribbbon) The 'typical' amphoteric substance, usually given, is aluminium hydroxide, Al(OH)3

Amphiprotic - IS in the syllabus. This substance not only reacts with both acids and bases but when it does it ACTS like a B-L base or a B-L acid. In fact it can react with other substances but it will react like a B-L acid (proton doner) or like a B-L base (proton acceptor).

 

[conman]

I think the simplest way to remember amphoteric is a substance which can act as an acid and as a base!!! That's what learnt from my tutor.

 

[renaethebest]

wow it isnt in the syllabus. but it was in our trials. bastards!

 

[kazan]

it is in the syllabus.. isn't it?


maybe its assumed for yr 11 or something?

 

[Roobs]

i'll support Nakashima's definition. but we DO need to know about amphoteric substances, in the HSC, but only in the context of metal and non metal oxides.

 

[tristambrown]

i think amphoteric is in the syllabus. we got it in our trials too (especially how to identify where they occur in the periodic table Diagonally to the right on the border between metals and gasses - the mettaliod divide with only one or two exceptions that we dont have to know. .. the divide is diagonally down to the right from boron and Al through silicon, germanium and arsenic- just know where it starts n u can find it on the table with no worries)

amphoteric oxides: react both with acids and bases in a NEUTRALISATION reaction to form H2O and Salt

Neutral Oxides (CO) do not react with acidic OR Basis oxides

Acidic Oxidex - react with water to form an acid AND OR react with bases to form H2O and Salt

Basic Oxides - react with acids to form H2O + salt and DOES NOT react with bases.

 

[gerg tenrab 07]

one of the most common amphoteric substances is water, or thats what my teacher told me

 

[Alfred_rulz]

AMPHOTERIC - Amphoteric substances are those which reacts with acids and can also react with bases.

P2O5(s) + 3H2O(l) → 2H3PO4(aq) (phosphoric acid)
or P2O5(s) + 6NaOH(aq) → 3H2O(l ) + 6Na+(aq) + 2PO43–(aq)

HSC Questions will often ask to provide an equation with states of matter as well

 

[mzduxx2006]

simply put. amphoteric means it can act as both an acid and a base when reacted with water.

heres an equation.

NaHCO(3) ----> Na + HCO(3) -

HCO(3) + H20 ---> H(3)0CO (2) + OH (BASE)

H(3)OCO(2) + H20 ----> 2HCO + H30 (ACID)