Preparation of small volumes of gases.
Phase transition is when a substance changes from a solid, liquid, or gas state to a different state. Every element and substance can transition from one phase to another at a specific combination of temperature and pressure.
Explanation:
if the first one was just O, then:
i) no of moles = mass/ molar mass
2= m/ 16
m = 16*2
m = 32g
ii) the second answer would be the same.
i can think of 3 subatomic particles found in a nucleus protons, neutrons, and electrons