Google chrome only uses half iPad page

I would uninstall it. Press on the Google Chrome App and hold it until it begins to wiggle. Then click the X and that should remove it. I would do a hard reboot at that time. Hold down the Home and Wake/Sleep buttons at the same time for about 15-20 seconds until the Apple logo appears. Ignore the "Slide to power off" text if it comes up. You will not loose anything. Then reinstall the App again and see.

you uninstall it by holding the finger on the app until it wiggle and show you and X you click on to delete it

but first try to restart it

Restart your iPhone, iPad, or iPod touch - Apple Support