A PPA repository exists that deal with being able to use the controls and FN keys of your samsung device.
You can add it by using the command:
sudo add-apt-repository ppa:voria/ppa
Now you need to upgrade your apt cache by using:
sudo apt-get update && sudo apt-get upgrade
Now you can install the 2 packages that give back access to FN keys:
sudo apt-get install samsung-tools
sudo apt-get install samsung-laptop
These packages will let you configure fan speeds which can help you reduce heating problems
You can find more information about the Voria packages here
You may also consider installing Jupiter along with it which lets you select the CPU performance modes...This also helps in reducing heating...
To Install Jupiter-
Open the terminal and enter the following commands-
sudo add-apt-repository ppa:webupd8team/jupiter
sudo apt-get update
sudo apt-get install jupiter