Here i have some few shortcuts to work in Mozilla Firefox without a mouse.
Ctrl + w -> Close the active tab in a Firefox browser
Ctrl + k -> Move the cursor over to the Google search available in the firefox browser on the right hand side of the firefox browser window.
Ctrl + l -> Move the cursor over to the URL bar on the browser.
Ctrl + i -> To open the Page Info in Firefox
Ctrl + u -> To view the Page Source
Ctrl + n -> To open a new browser window