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.
Answer: 11.5 grams
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution
where,
Morality = 0.612 M
n= moles of solute
= volume of solution in ml = 100 ml
Now put all the given values in the formula of molarity, we get

Therefore, the mass of copper (II)nitrate required is 11.5 grams
Answer: C diamond has a different crystal structure from graphite
Explanation:
Answer
Do you think that the mole should be considered a base unit in the SI system?
The mole is not a base unit on a par with the six property base units; it cannot be used in significant physical–chemical comparisons until the subscript parameter p in mole-of-Ep has been given a certain “value”."
Explanation: