# Homework Help: Net ionic equations helppppp.

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2. ### NO!school rocks to the hundredth degree and is therefore > summerrrrrr

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1. Apr 29, 2007

### oceanflavored

i'm studying for my apchem exam. and rightnow; i'm currently reviewing my net ionic equations. but there's something i'm confused about in my ap chem book.

1. The problem statement, all variables and given/known data
the equation is:
CaF2 (aq) + 2HCl (aq) ---> 2HF (aq) + CaCl2 (aq)
and then the book says that the ionic equation is:
Ca2+ (aq) + 2F- (aq) + 2H+ (aq) + 2Cl- (aq) --> 2HF (aq) + Ca2+ (aq) + 2Cl (aq)

i understand when there's a solid (precipitate) you don't write it all out. because it doesn't dissolve. but wouldn't you write 2HF all out, as in you would write: 2H+ (aq) and 2F- (aq), or is there some other rule that i don't know about??

thanks to anyone who can help. i'd appreciate ittt :)

2. Apr 29, 2007

### oceanflavored

come on guysssss.you can do this.
i believeeeee.

3. Apr 30, 2007

### Kushal

this is a method of extracting hydrofluoric acid!! whereby CaF2 is an ore known as fluorite....well coming back to your problem...

As you know, acids exist as molecules in pure state. but when added to water... they dissociate.

e.g. HCl <------> H* + Cl-

HCl dissociates completely (or so) in aqueous mediem i.e water.... and so, exists as H* and Cl-

but HF does not dissociate completely. it has a very much lower tendency to ionise in water....and therefore exists mainly as HF molecules instead of H* and Cl-.... it's all about ionic equillibrium..... in which i'm not very expert!!!

hope to have helped you

4. Apr 30, 2007

### oceanflavored

oh okayy. thanks.
that helps a lottt :)
thanks superduper much.
ps: were you the one that said "school rocked to the 1000th degree?"
because that's just strangeeeeee.
in a good way :)

5. May 2, 2007

### Kushal

nope....i don't think so...duh