Question

Calculate the mass of 1 molecule of chlorine.

Answer 1

Hint: To solve this firstly identify if the chlorine molecule is a monatomic, diatomic or triatomic molecule. Then use the atomic mass of chlorine to find the molecular mass of chlorine. Mass of one molecule will be the product of atomic mass and number of atoms.

COMPLETE STEP BY STEP SOLUTION:
We know that a molecule is a group of atoms which are bonded together and represent the smallest unit of a compound which takes part in a chemical reaction.
An element contains a single variant of the atom and thus cannot be broken and can exist as either an atom or a molecule. It depends on several stability factors. Some elements exist as atoms like argon whereas others exist as a molecule like nitrogen.
Chlorine is a halogen and its atomic number is 17. Naturally, chlorine exists as a diatomic molecule.
We know that the atomic mass of chlorine is 35.5 g/mole.
We have also discussed above that chlorine exists as a diatomic molecule.
Therefore, its molecular mass is twice its atomic mass.
So the mass of 1 molecule of chlorine will be $35.5\times 2$ g/mole = 71 g/mole.

Therefore, the correct answer is 71 g/mole.

Note: The molar mass of any substance is the number of grams of the substance in its molecular form which contains Avogadro’s number atoms of the substance. This is due to the fact that the mass of a substance is dependent on the molecular weight of the substance. It is defined by the number of protons and neutrons in the atom.