Among the choices, the polyatomic ion is only the third choice, NH4+ where it is composed of nitrogen one atom of nitrogen and 4 atoms of hydrogen. Choice 2 is a monoatomic atom being composed only of calcium. Then, the first and fourth choices are not ions because they are not charged.
The law of conservation of mass states that mass or matter cannot be created or destroyed, only transferred or recombined.
For chemical equations, this law means that each element must be accounted for equally both for reactants and products. So the same numbers of each atom must match on each side, hence the necessity for balancing the chemical equation accurately. This created a field of chemistry called Stoichiometry, which accounts for the conservation of matter throughout chemical reactions and processes.


ok, now press calculator. i dont have it now.
Answer:
The water will eventually become the same temature (A)