Which metal reacts quickest in this group (li, na, k, rb and cs) why?

What’s the percent by mass of carbon in c10h14n2

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

Aroom with dimensions 7.00m×8.00m×2.50m is to be filled with pure oxygen at 22.0∘c and 1.00 atm. the molar mass of oxygen is 32.0 g/mol. how many moles noxygen of oxygen are required to fill the room? what is the mass moxygen of this oxygen?