Check out the link I've included below, it has a great play by play with instructions on how to conduct this experiment and explanation as to what happens and how.
There's really not a quick answer for you, due to the answer will vary depending on variables of the experiment, example: how long did you leave the egg in the vinegar or was the egg raw or boiled, etc.
Use the link below and good luck with your experiment.
When you put an egg in vinegar, it will begin to soften the shell ,then in a few days hard white shell will be gone to point where you will see the yoke through the skin behind shell and the egg will swell up and get tough to point where you can hold it n your hand! hope this was a help, shutterfly.
This was such a great question, that I thought I would let my kids do the experiment for fun. So, I used the same website that I had provided for you earlier and this is what actually happened.
It bubbles-why - when calcium carbonate (the egg) and acetic acid (the vinegar) combine, a chemical reaction takes place and carbon dioxide (a gas) is released. This is what the bubbles are made of.
The chemical reaction keeps happening until all of the carbon in the egg is used up-it takes about 1 day.
When you take the egg out of the vinegar it's soft because all of the carbon floated out of the egg in those little bubbles.
If you leave the same egg sitting out on the table for another day-it will become hard again-why-the calcium left in the egg shell gets carbon back from the carbon dioxide in the air that we breathe.
As I said before, there are still variables in this experiment that will cause the reaction to differ. For a really cool EXTRA- if you used a raw egg, once the shell has softened, you can place the egg in water and it will absorb and expand until the shell finally bursts.
Thought you may be interested in this, hope it's helpful!