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th3m0ment

137 posts since Oct '03
- 18 Oct `07, 3:11PM
  
  anyone can explain the difference between H2O and H2O? aren’t they the same?
poon cho tang

127,607 posts since Sep '04
- 18 Oct `07, 3:14PM
  
  aqueous H2O = water dissolved in water?
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^tamago^

★.

51,105 posts since Sep '03
- 18 Oct `07, 3:15PM
  
  same, unless it's H³0+ (aq).
th3m0ment

137 posts since Oct '03
- 18 Oct `07, 3:33PM
  
  if they are the same, why do they have 2 different symbols?
dbowie

4,041 posts since Mar '07
- 18 Oct `07, 3:34PM
  
  eh..
  aquerous means in water..
  (l) also means in water..
  except u always put H2O as (l)..
poon cho tang

127,607 posts since Sep '04
- 18 Oct `07, 3:40PM
  
  pedantically,
  
  (l) could be more to indicate that water, as a participating reagent, is in its liquid state
  
  (aq) has a double meaning, inferring that water is reacting both in its liquid state and "dissolved" as H+ and O2- ions
starmoonsun

64 posts since Jul '07
- 18 Oct `07, 5:06PM
  
  huh???
  i thought (l) is because it is like distilled water, no ions disassociate
  then aqueous will have
  -confused-
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^tamago^

★.

51,105 posts since Sep '03
- 18 Oct `07, 9:20PM
  
  er, if you are O level, just take H20 as (l) can liao.
  for A level it gets a bit more complicated.
tanjun

1,057 posts since Jan '05
- 18 Oct `07, 9:40PM
  
  For me, I will put the state symbol of H2O as l. The state symbol (aq) refers to a solution that is dissolved in water. It makes no sense to say that H2O dissolves in H2O.
  
  For example: HCL (aq) refers to hydrochloric acid while HCL (g) refers to hydrogen chloride gas. Hydrochloric acid is a product when hydrogen chloride is pumped and dissolved in water.
  
  Hydrochloric acid has acidic properties while hydrogen chloride gas doesn't.
  
  Thus, my stand on H2O(l) result.
rain-coat

492 posts since Sep '07
- 18 Oct `07, 11:34PM
  
  H2O is (l) since its in the liquid form, just like eg. NaCl(l) in molten state. (aq) is for substances dissolved in water eg. NaCl(aq) sodium chloride solution.
ultranova3

128 posts since Aug '07
- 20 Oct `07, 3:07AM
  
  Originally posted by poon cho tang:
  
  pedantically,
  
  (l) could be more to indicate that water, as a participating reagent, is in its liquid state
  
  (aq) has a double meaning, inferring that water is reacting both in its liquid state and "dissolved" as H+ and O2- ions
  
  O2-??
  I thought it is OH-.
  2H2O H3O+ + OH-
  How do we get oxide ion?
  O2- + H2O 2OH- ???
sirron kcuhc

276 posts since Oct '07
- 20 Oct `07, 3:08AM
  
  1+1=2
unclebutcher

2,819 posts since Oct '06
- 20 Oct `07, 8:32PM
  
  Originally posted by th3m0ment:
  
  anyone can explain the difference between H2O(l) and H2O(aq)? aren't they the same?
  
  for o levels, no such thing as H2O (aq). aq means the compund has dissociated in a solvent, which is illogical for h2o as h2o cannot dissociate in h2o.
Moderator

Darkness_hacker99

31,746 posts since Jun '05
- 20 Oct `07, 11:55PM
  
  Originally posted by unclebutcher:
  
  for o levels, no such thing as H2O (aq). aq means the compund has dissociated in a solvent, which is illogical for h2o as h2o cannot dissociate in h2o.
  
  How about A Level?
  
  I don't mind to learn more
ultranova3

128 posts since Aug '07
- 21 Oct `07, 1:08AM
  
  I think the term should be auto-protonation of water/self-ionization of water/auto-dissociation of water.
  
  2H2O(l) H3O+(aq) + OH-(aq) Kw = 1 x 10^-14
  Kw is water dissociation constant. You can find more about this in acid-base equilibria.
HyuugaNeji

1,648 posts since Jun '05
- 21 Oct `07, 1:12AM
  
  When they put H2O(l), it usually mean the water does not take part in the chemical reaction.
  
  Bluff you la.
  
  Water(l) is put in there to confuse pple.
  
  Edited by HyuugaNeji 21 Oct `07, 1:16AM
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Darkness_hacker99

31,746 posts since Jun '05
- 21 Oct `07, 1:20AM
  
  Originally posted by HyuugaNeji:
  
  When they put H2O(l), it usually mean the water does not take part in the chemical reaction.
  
  Bluff you la.
  
  Water(l) is put in there to confuse pple.
  
  But But But...
  
  Say Alkali metal react with water.
  
  K(s) + H2O(l) --> KOH(aq) + H2(g)
  
  So water take part in the chemical reaction right?
HyuugaNeji

1,648 posts since Jun '05
- 21 Oct `07, 1:42AM
  
  Originally posted by Darkness_hacker99:
  
  But But But...
  
  Say Alkali metal react with water.
  
  K(s) + H2O(l) --> KOH(aq) + H2(g)
  
  So water take part in the chemical reaction right?
  
  I say usually ma. Not always.
Moderator

Darkness_hacker99

31,746 posts since Jun '05
- 21 Oct `07, 1:49AM
  
  Originally posted by HyuugaNeji:
  
  I say usually ma. Not always.
  
  I know
dbowie

4,041 posts since Mar '07
- 21 Oct `07, 1:51AM
  
  This question is puzzling.
ultranova3

128 posts since Aug '07
- 21 Oct `07, 2:03AM
  
  Originally posted by Darkness_hacker99:
  
  But But But...
  
  Say Alkali metal react with water.
  
  K(s) + H2O(l) --> KOH(aq) + H2(g)
  
  So water take part in the chemical reaction right?
  
  If you want, explain it using equilibria. For simplicity, I will use H+ instead of H3O+.
  
  H2O H+ + OH- Reaction 1 (equilibrium reaction)
  2K(s) + 2H+(aq) --> 2K+(aq) + H2(g). reaction 2 (forward reaction)
  This reaction will always go forward.
  Since H+ is being consumed in reaction 2, concentration of H+ will decrease. As such, by Le Chartelier's Principle, the system will try to produce more H+ in reaction 1 so that the system reaches the equilibrium, by shifting the equilibrium of reaction forward (to the right) favouring production of H+ and OH-.

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