[DarkLightA]

I'd really, really, really appreciate it if someone read through the following any commented on any mistakes, bad thinkings etc. I know it's a medium-long read, but I would be forever thankful!!!!!

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So, I know the following rules:
1. Acid + Alkali ==> Salt + water
2. Acid + Metal ==> Salt + hydrogen
3, Acid + Metal Carbonate ==> Salt + CO2 + H2O
[4. Metal + H2O ==> alkali (? Like KOH, is that an alkali? We learnt that metal oxides are basic.) + Hydrogen]

Examples of my thinking:
1. Alkali + Acid ==> Salt + Water
NaOH + HCl ==> NaCl + H2O
and since NaCl has a valence of 0 (do you call it valence in compounds?) it works.

But, for something like CaO + HCl:
CaO + HCl ==> CaCl + OH
There's obviously missing an H there, so we add it from the only term of CaO and HCl with H in it:
CaO + 2HCl ==> CaCl2 + H2O
And CaCl2 has valence 0, so it works.

2. Acid + Metal ==> Salt + hydrogen
K + HCl ==> KCl + H
It has to be H2, so:
K + 2HCl ==> KCl2 + H2
KCl2 would have a + valence, so it wont work, however:
K2 + 2HCl ==> 2KCl + H2
And that has a valence of 0, so it works.

Other example:
Ca + HCl ==> CaCl + H
Has to be H2:
Ca + 2HCl ==> CaCl2 + H2
CaCl2 has valence 0 so it's perfect =)

3. Acid + Metal Carbonate ==> Salt + CO2 + H2O
HCl + K2CO3  ==> K2Cl + CO2 + H2O
That seems right to me: K2Cl is a happy compound with full shells.

HCl + CaCO3 ==> CaCl + HO + CO2
Okay, there's obviously a problem with H2O here, we're missing a H.
2HCl + CaCO3 ==> CaCl2 + H2O + CO2
And this seems good. CaCl2 is happy!

4. Metal + H2O ==> alkali + hydrogen
K + H2O ==> KOH + H
but you can't just have H, you have to have H2, so:
K + 2H2O ==> K(OH)2 + H2
But K(OH)2 isn't "happy", as it has a valence of +, but an extra K would fix that:
2K + 2H2O ==> 2KOH + H2
and that seems good.

But how about:
Ba + H2O ==> BaOH + H
Has to be H2..
Ba + 2H2O ==> Ba(OH)2 + H2
and then that looks good.

[Borek]

No such things as valence in compounds, no idea what you refer to.

Surprisingly, your reactions are balanced OK. Usual approach is to decide formulas first, balance later.

[BetaAmyloid]

I read through them (but didn't check your balanced equations) and from the reactants and products everything looks fine to me.

**Except the following**

For #3 it should be:
K₂CO₃ +2HCl → 2KCl + CO₂+ H₂O (Remember, K₂ is not part of K, it is the charge of CO₃)
 
I'm not positive for the very last one with Ba and H₂O!

P.S. You can usually find these through google also.

Hope this helps

[BetaAmyloid]

Well, you may want to ask Borek or a professional handler of chemicals to check K₂CO₃ since above he says that they looked okay.

I think it should be this though - although I may be wrong! 

Ask Borek, he'll know.

[Borek]

Nah, you are right - K₂Cl is wrong. My mistake. I have just skimmed and missed it. I have also missed K₂ instead of 2K in #2.

Should not check such things at 1 am.

[BetaAmyloid]

Whoa! I beat Borek at something.

Mmm...let me just take this moment in. (Kidding)

Time differences are big from you to me! It's only 7:00 P.M. here!

[DarkLightA]

Nah, you are right - K₂Cl is wrong. My mistake. I have just skimmed and missed it. I have also missed K₂ instead of 2K in #2.

Should not check such things at 1 am.

This is where my thought of "valence" comes in:
K2Cl is 2 K, element 19, and 1 Cl, element 17. Add it together: 38+17=55, and that's one OVER the 54 "noble" value. So you have to get 1 more under, which would work with chlorine, so it has to be:
2KCl


I think this works =D

[Borek]

I think this works =D

Only sometimes. NaCl is 11+17=28, nowhere near "noble values" of 10, 18 or 36.

[DarkLightA]

I think this works =D

Only sometimes. NaCl is 11+17=28, nowhere near "noble values" of 10, 18 or 36.

Okay, I realize this now, but I don't tend to do it with atomic numbers but rather valence. Then it seems to work every time =) Including NaCl.

[DarkLightA]

K₂CO₃ +2HCl → 2KCl + CO₂+ H₂O (Remember, K₂ is not part of K, it is the charge of CO₃)

That's what I wrote, but I didn't have subscript, sorry.

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About the Ba + H2O, I found the following:

Ba(s) + 2H2O(l) ---> Ba(OH)2(aq) + H2(g)


Thanks for all your *delete me*

"DLA"

[DarkLightA]

NaOH(aq) + HCl(aq) ==> NaCl(s) + H2O(l)
CaO(aq) + 2HCl(aq) ==> CaCl2(s) + H2O(l)
K2(s) + 2HCl(aq) ==> 2KCl(s) + H2(g)
Ca(s) + 2HCl(aq) ==> CaCl2(s) + H2(g)
HCl(aq) + K2CO3(s)  ==> K2Cl(s) + CO2(g) + H2O(l)
2HCl(aq) + CaCO3(s) ==> CaCl2(s) + H2O(l) + CO2(g)
2K(s) + 2H2O(l) ==> 2KOH(aq) + H2(g)
Ba(s) + 2H2O(l) ==> Ba(OH)2(aq) + H2(g)

is this correct?

[Borek]

but I don't tend to do it with atomic numbers but rather valence. Then it seems to work every time =) Including NaCl.

Please elaborate, again it is not clear what you mean.

[Borek]

CaO(aq)

K2(s)

K2Cl(s)

These are wrong, for various reasons.

[DarkLightA]

but I don't tend to do it with atomic numbers but rather valence. Then it seems to work every time =) Including NaCl.

Please elaborate, again it is not clear what you mean.

Sorry, I realize I've made a mistake. I meant the ions it forms.

For example:

CaOH has two parts: Ca and OH.
O makes -2 ions.
H makes +
Together, -2+1=-1
So I say that OH has an "ionic charge" of -

Ca is simple enough: 2+
+2-1=+1
It has to be 0, so we need another - somewhere.
Looking back, OH is -, so by adding another of them it'll be 0:
Ca(OH)2

Ca: 2+
OH: O: 2- H: + TOTAL: -
OH: O: 2- H: + TOTAL: -

So +2-1-1=0 and that works.


Example 2:

BaCl
Barium makes 2+
Chlorine makes -
Together, +2-1=+1
So to make it 0, we need another -. This can be found in Cl, so we add one of them:
BaCl₂
And there:
Ba: +2
Cl: -
Cl: -
In total: +2-1-1=0, so it's happy.

[Borek]

CaOH has two parts: Ca and OH.

I would put it "calcium hydroxide has two parts" - CaOH doesn't exist (or at least at this stage you have no idea if it does or not).

O makes -2 ions.
H makes +
Together, -2+1=-1
So I say that OH has an "ionic charge" of -

That's not bad, but dangerous - sooner or later you will hit element that can have several valencies and it won't be that easy. Besides, OH^- is not a compound made of two ions O^2- and H⁺ - it is "just" OH^-.

Ca is simple enough: 2+
+2-1=+1
It has to be 0, so we need another - somewhere.
Looking back, OH is -, so by adding another of them it'll be 0:
Ca(OH)2

Molecule must be neutral, so if we know that calcium cation has charge +2 and OH group -1, it must be Ca(OH)₂. OK