Question

What is the molecular weight of ${{C}_{2}}{{H}_{4}}$?

Answer 1

Hint: Whenever molecular weight has been asked to calculate, we must calculate the molar mass of the compound. We should not calculate the molecular mass. Both molecular mass and molar mass are different from each other.

Complete step by step solution:
Molecular weight is also known as Molar mass. Molar mass is defined as the mass of one mole of the substance. It is expressed in the g/mol unit.
Steps needed to be followed to find the molar mass.
-First, identify the formula of the given molecule or compound.
-Determine the number of moles of atoms present in the given molecule or compound.
- Multiply the mass of each atom with the number of moles of the atom.
- Do this for every element present in the compound.
- Finally add all the values.
- These obtained values are expressed in the g/mol unit.
In ${{C}_{2}}{{H}_{4}}$ molecule,
There are 2 moles of carbon atoms and 4 moles of hydrogen atoms.
Molar mass of ${{C}_{2}}{{H}_{4}}$
= $2\times 12.01+4\times 1.01$
=$24.02+4.04$
=$28.06gmo{{l}^{-1}}$

Therefore, molecular weight of ${{C}_{2}}{{H}_{4}}$ is $28.06gmo{{l}^{-1}}$.

Additional Information:
- ${{C}_{2}}{{H}_{4}}$ is an ethylene molecule.
- It belongs to the alkane family.
- The IUPAC name is ethane.

Note: Differences between molar mass and molecular mass are given in the table below.

MOLAR MASS	MOLECULAR MASS
Ii is the mass of one mole of a substance.	It is the mass of the molecule.
It is expressed in g/mol.	It is expressed as amu.
It is also known as the molecular weight.	It determines the mass of the single molecule..