b. o2
oxygen is diatomic because 1 molecule is made of 2 atoms of oxygen
Answer:
a) Volume of vial= 9.626cm3
b) Mass of vial with water = 62.92 g
Explanation:
a) Mass of empty vial = 55.32 g
Mass of Vial + Hg = 185.56 g
Therefore,

Density of Hg = 13.53 g/cm3

b) Volume of water = volume of vial = 9.626 cm3
Density of water = 0.997 g/cm3

Since water has a density of about 1g/mL, and we are assuming HCl and NaOH are mostly water, the total mass of the 2 solutions is 100 g.
Due to the conservation of mass, the mass of product must equal the total mass of reactant, therefore the final mass must also be 100 g.
0.023, to do it, just simply divide the energy value by 1000.