Question

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

Answer 1

Hint: Heavy water or ${D_2}O$ is made of Deuterium (it is the isotope of hydrogen and also known as Heavy hydrogen and its symbolic name is $^2H$ or D) and Oxygen. Its chemical and physical properties are different from normal water due to the presence of heavy hydrogen isotopes.

Complete answer:
The nucleus of a deuterium atom contains a neutron and a proton, while the nucleus of a protium (normal hydrogen) atom contains only a proton. A deuterium atom is about twice as large as a protium atom due to the extra neutron.
The mass of one mole of a compound and the number of grams per mole of a compound are described by its molar mass. To put it another way, the molar mass is the total mass in grammes of all the atoms that make up a mole of a specific molecule. As a result, molar mass is measured in grams per mole.
Steps to calculate molar mass of any compound is given below:
Calculate the number of atoms in each element in the compound using the chemical formula.
Multiply each element's atomic weight by the number of atoms present in the compound.
Add it up and allocate a unit of grams/mole.
Molar mass of deuterium $ = $ $2.0141$ $gram.mo{l^{ - 1}}$
Molar mass of Oxygen $ = $ $15.9994$ $gram.mo{l^{ - 1}}$
Since there are two atoms of deuterium and one atom of oxygen, the molar mass of heavy water is calculated as –
Molar mass of heavy water ${D_2}O$ $ = $ $2.0141 \times 2 + 15.9994$
Molar mass of heavy water ${D_2}O$ $ = $ $20.0276$ $gram.mo{l^{ - 1}}$

Note:
The weight of a heavy water molecule, on the other hand, is not significantly different from that of a typical water molecule, since the single oxygen atom makes up about $89$ percent of the molecular weight of water, rather than the two hydrogen atoms.