Facebook is heavily distracting with pictures and games--add in chat messages and you'll be spending more time on the site than you originally intended. This is usually because every time someone sends you a message, an alert sound plays to notify you of its presence. Not only that, but the title bar of your browser will start displaying that they have messaged you. Here are three quick steps to turning off the alert sound, or disabling chat completely if you choose to do so:
Step 1: Login to your Facebook account.
Step 2: Locate your chat window. For the new style of chat: the bar will be on the right side of the page, or if the window isn't maximized it will be near the bottom and pop upward. For the old style of chat: the window will be in the bottom right corner.
Step 3: Click on the Settings cog located in either the top right or bottom right corners of the chat window (depending on the version/size you are using). Choose to disable Chat Sounds, the Available to Chat feature, or both.
You can now enjoy a quiet Facebook experience with no alert sounds, or even chat if you disabled it. This will help keep you focused on what you're doing, instead of always popping back into the Facebook tab on your browser to see what's going on in chat.