Log in to your Facebook and on the tab click on the "More" and then click on "Manage Tabs".
After clicking on the "Manage Tabs" it will pop up a small window where you will see a tab "Add or remove tabs" click on that.
Now we are on the final page, where you can see all the apps you have installed. Click on the small "x" which ever app you want to remove.
That's all for this post, hopefully it helps you. :)