Lahearle

If I combine a compound which contain a ratio of 3/8 hydrogen/oxygen and heat it to 2600 F, according to PV = nRT how much will the pressure increase when it reaches ignition temperature (1058 F), and how big do I need the container to avoid it exploding and spewing lava everywhere? Yes I am noob so please talk stupid to me. The compound has only hydrogen, carbon, oxygen and nitrogen.