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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: hard on August 25, 2008, 06:24:15 pm

Title: help please.
Post by: hard on August 25, 2008, 06:24:15 pm: i have this question right, can you please tell me if i'm right regarding the full equations.

reaction Equations

Hydrocholric acid + calcium carbonate Full: $HCl(aq) + CaCO3(s) ---> CaCl2(aq) + CO2(g) + H2O(l)$

Hydrochloric acid + copper oxide Full: $CuO(s) + 2HCl(aq) --> CuCl2(aq) + H2O(l)$

Hydrochloric acid + magnesium Full: $Mg(s) + Cl(aq)----> MgCl2(aq) + H2(g)$
.
Hydrochloric acid + sodium hydrogen carbonate Full: $HCl(aq) + NaHCO3 --> NaCl(aq) + H20(g) + CO2(g)$

Hydrochloric acid + ammonia Full: $NH3(aq) + HCl(aq)----> NH4(aq) + OH(aq)$

hydrochloric acid + silver nitrate Full: $HCl(aq) + AgNO3(aq) ---> AgCl(aq) + HNO3(aq)$

however my concern here is the ionic reactions. Can someone please show me how to do then? i know that it is the spectator ions that are left out however the actual equation we havn't done yet, so would any one care to explain? thanx.
Title: Re: help please.
Post by: cara.mel on August 25, 2008, 06:46:08 pm: Aside from a typo, they're right :D (although I am not sure about hydrochloric acid + ammonia, but charges balance and stuff so it *looks* right at least)

For ionic equations, they're pretty much the same thing.
Eg in equation 1
CaCO3(s) + 2H+(aq) -> Ca2+ (aq) + CO2 (g) + H2O (l)
As Cl is aq on both sides, its not included
Everything balances as normal, don't worry about how the full equation is balanced.
From one example you should be able to do the rest :)
Title: Re: help please.
Post by: hard on August 25, 2008, 06:48:50 pm: thanks caramale, that's all i needed.
Title: Re: help please.
Post by: hard on August 26, 2008, 12:05:32 am: sorry but for the ionic, i've learnt thorugh the text book that usually or always the products are of aqueous solution. then a precipitation reaction occurs or something, and one turns solid or changes state, i.e. in the products. can you show me the first two in terms of their ionic equations? trhannxxx
Title: Re: help please.
Post by: cara.mel on August 26, 2008, 07:32:01 am: Like this one?

NaCl(aq) + AgNO3(aq) -> AgCl(s) + NaNO3(aq) (I sure hope AgNO3 is aqueous, if it isn't just pretend it is, I don't do chem any more I've forgotten a lot :P)
Ionic equation:
Ag + (aq) + Cl-(aq) -> AgCl (s)
Title: Re: help please.
Post by: hard on August 26, 2008, 08:25:33 am: yer that's what i mean thought, in the test book, i've done questions similar to that one you've just done but take this for example.

Hydrochloric acid + magnesium Full: Mg(s) + Cl(aq)----> MgCl2(aq) + H2(g)

i got a solid, aqueous and gas in the equation.
what do i leave and what do i take?
Title: Re: help please.
Post by: bturville on August 26, 2008, 11:05:21 am: if its a metal, its solid. if its a soluble compound, its aqueous. it helps to remember a few of the basic solubility rules in case you are not sure what compounds are soluble or not.

sorry if that sounds really obvious, i didn't quite get what you meant by "what do i leave and what do i take"
Title: Re: help please.
Post by: cara.mel on August 26, 2008, 12:39:32 pm: Edit: This post is incorrect, all future readers should ignore it
(yay for lack of sleep)

Quote from: hard on August 26, 2008, 08:25:33 am
yer that's what i mean thought, in the test book, i've done questions similar to that one you've just done but take this for example.

Hydrochloric acid + magnesium Full: Mg(s) + Cl(aq)----> MgCl2(aq) + H2(g)

i got a solid, aqueous and gas in the equation.
what do i leave and what do i take?

In that one, there are no spectator ions, everything reacts so ionic equation is the same as the full one
(being picky, 2HCl :P)
Title: Re: help please.
Post by: Mao on August 27, 2008, 10:16:33 am: $Mg(s)+2H^+(aq)\to Mg^{2+}(aq)+H_2(g)$

the Cl doesnt do anything :P
Title: Re: help please.
Post by: hard on August 27, 2008, 03:34:54 pm: ohh thanks yes i get it now!
Title: Re: help please.
Post by: cara.mel on August 27, 2008, 03:41:00 pm: yeah i is idiot :(
Title: Re: help please.
Post by: hard on August 27, 2008, 03:49:05 pm: must be a pretty smart idiot :P
Title: Re: help please.
Post by: Collin Li on August 27, 2008, 04:50:04 pm: I disagree. Hydrochloric acid is covalently bonded, so it is not a spectator ion.
Title: Re: help please.
Post by: Mao on August 27, 2008, 08:03:34 pm: i believe dissociation occurs first, it is, afterall, a very strong acid.
Title: Re: help please.
Post by: Lycan on August 27, 2008, 08:18:41 pm: Quote from: coblin on August 27, 2008, 04:50:04 pm
I disagree. Hydrochloric acid is covalently bonded, so it is not a spectator ion.

I agree with the disagreement. Spectator ions only occur when something is ionically bonded which HCl is not.