Problem- In 1774, Joseph Priestley discovered that mercury(II) oxide decomposes on heating to elemental mercury and a gas, later called oxygen. If 56.0 g of mercury(II) oxide is heated and 26.0 % of it decomposes, what is the pressure of oxygen gas in a 621 mL container at 25oC?
A.1.32 atm
B.10.1 atm
C.5.17 atm
D.2.64 atm
E.5.30 atm
Please explain how you came up with answer I really want to understand how to solve this