Ow can I get my fb chat bar back

Which app are you using for facebook? But as far i know facebook chat doesn't work on the iPad as It's not Flash. But you can use the AIM app. It does Facebook chat on ipad.

I would assume most people use the official Facebook app. In that case, the bar down the right hand side listing friends is to do with chat, so that is probably what the OP is talking about. If you tap on an online friend, a chat window opens.

I've never seen that bar/column disappear, wouldn't know how to get it back if it did. All I can say is make sure you are on the Newsfeed and the left side menu is closed.