gas law test rant

A DISASTER:
COMMON ERRORS- UNABLE TO DEDUCT WATER VAPOR PRESSURE FROM TOTAL PRESSURE
FAULTY SIG FIGS
NOT USING PARTIAL PRESSURE TO GET MOLES OF A SPECIFIC GAS
THINKING THAT THERE IS SUCH A THING AS PARTIAL VOLUME (NEVER TEACH THAT EXAMPLE EVER AGAIN)
GRAHAMS LAW- NOT SQUARING BOTH SIDES!!!
NO TEST-TAKING SKILLS! NOT USING THE DATA FROM THE QUESTION!!! NOT EVEN USING THE COMBINED GAS LAW HINT!!!
THINKING OXYGEN IS O INSTEAD OF O2
SAYING N = RT/PV !!!
NOT SOLVING MW = DRT/P