The percentage by mass of oxygen in the compound
find the total mass=( 1.900+ 0250 +0.850) = 3
the percentage mass mass of oxgyen/total mass x100
that is (0.850/3) x100=28.33%
Answer:
The new pressure is 44.4 kPa.
Explanation:
We have,
Initial volume, 
Initial pressure, 
It is required to find the new pressure when the volume is increased to 50 ml. The relationship between pressure and volume is known as Boyle's law.

is final pressure

So, new pressure is 44.4 kPa.
An atom of Oxygen. Contains:
Protons = 8
Electrons = 8
Neutrons = Mass number - Number of protons = 18 - 8 = 10
Neutrons = 10.
Ionic compounds. because when in solid form they are held firmly in place therefore they cannot move to conduct electric current.