Question

determine the pressure that must be excreted on 200 grams of oxygen to contain it in a 2.oo l vessel at 30 degrees celcius

Answer 1

Note the correct spelling of celsius.

Use PV = nRT and for n use n = grams/molar mass. Don't forget T must be in kelvin. Also, note your typo. I'm sure you meant exerted and not excreted. We usually don't excrete oxygen.