#double replacement

The chime of the phone had caught both girls off guard. They didn't expect her to have one, considering her nature. Nonetheless, now it was there. Both stared at the text message, and at the ID. None of them knew who "Fay" was, but since whoever they were seemed to know Ivy, this might help them.

"Oh, really? Let me take a look."

"Neko thinks we should go!"

Double displacement

This reaction takes place when a soluble and insoluble compound reacts w/ each other to yield another substance.

Water (H2O), a gas like CO2 and an insoluble compound form in the product side are the evidence of this reaction.

These reactions are in the general form of :

Here's a quick explanation on double replacement reactions:

So remember the single replacement reaction? That was when one element moves to a different place. 

Well a double replacement reaction, as you might assume, is when two elements move.

Here's an example:

*NOTE- Anything highlighted is a polyatomic atom. Polyatomic atoms are several covalently bonded atoms that, as a unit, can be ionically bonded to other elements.*

This is what happens in that reaction:

The sodium bonds with the acetic acid, because they have opposite charges, to form sodium acetate. 

The hydrogen bonds with the bicarbonate, because they have opposite charges, to make carbonic acid (do note that the two hydrogen atoms do bond, but are shown separate so that you can see the polyatomic atom) . Now, carbonic acid is avery unstable substance. So what happens is that it splits into H2O and CO2 (water and carbon dioxide). The carbon dioxide will bubble away and eventually you will be left with water and sodium acetate, an aqeous sodium acetate solution.