What pressure is needed to compress 455ml of oxygen gas at 2.50 atm to a volume of 282ml?

As per Boyle’s law

For a given amount of gas, Pressure is inversely proportional to its volume, at constant temperature

The expression for Boyle’s law is given by  

 (at constant T)

(k is the constant)

when there is a change in pressure and volume we make use of the expression  

and are the initial pressure and initial volume and  

and are the final pressure and final volume

Plugging in the values  

(Answer)

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.