Open Facebook URL in Facebook App I know using the fb://URL scheme I can open certain links in the Native Facebook App, 

e.g. fb://page/137947732957611 will open the Apple Facebook page.

Is there anyway I can open pages without knowing the pageid though, eg so I can just open https://www.facebook.com/Google but within the Facebook App?
No it's not possible!

The reason is that the Facebook url scheme needs a unique ID for open a certain page and if you look the screenshot below you can see that the "Google" is Name and Username.