Question

What is the molar mass of heavy water ${D_2}O$?

Answer 1

We have to know that the molar mass of a chemical compound is equal to the mass of the sample which is present in the compound and it should be divided with the amount of substance present in the sample. And the molecular weight is another term of molar mass which is used for the molecular compounds. And this is an intensive property. Because, it will not depend on the size of the sample. The molar mass is expressed in terms of kg/mol.

Complete answer:
We need to remember that the deuterium is a form of water which is replaced by one hydrogen isotope, $^1H$ that normally present in the water molecules by deuterium or$^2H$. There is a difference between hydrogen and deuterium. Because, both have the same number of neutrons, which is equal to one. But the hydrogen does not contain any neutrons, the deuterium contains one neutron.
The molar mass of deuterium is equal to $2.0141g/mol$ .
The heavy water contains one oxygen atom and two deuterium isotopes. And the molar mass of oxygen is equal to $15.9994g/mol$.
Hence, to find the molar mass of water, we have to add each of the masses. So that we get the molar mass of heavy water.
Molar mass of heavy water $= 2 \times 2.0141 + 15.9994 = 20.0276g/mol$
Therefore, the molar mass of heavy water is, ${D_2}O$ is equal to $20.0276g/mol$

Note:
We need to know that the heavy water is a type of water which contains deuterium isotope instead of the hydrogen, the hydrogen, $^1H$. And the heavy water has a unique structure and chemical properties. Thus, it is used for the production of weapons and nuclear power reactors. The scientific name of heavy water is deuterium oxide. Which contains two atoms of deuterium isotope and one oxygen atom.