Answer:
Number of protons and neutrons
Its chemical formula H2O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. "Water" is the name of the liquid state of H2O at standard conditions for temperature and pressure.
Answer:
1. analyze the samples while they are frozen
stuff can react differently when it's colder
hope I could help good luck