Question

One mole of chlorine gas is equal to how many grams?

Answer 1

Determine the formula of chlorine gas. Using the periodic table determine the molar mass of chlorine gas. Using the relation between moles, mass and molar mass calculate the mass of one mole of chlorine gas in grams.

Formula Used: ${\text{mole = }}\dfrac{{{\text{mass}}}}{{{\text{ molar mass}}}}$

Complete step-by-step answer: Chlorine gas is a diatomic gas having chemical formula ${\text{C}}{{\text{l}}_{\text{2}}}$. By referring to periodic tables we can say that element chlorine (${\text{Cl}}$) is a halogen and present in the VIIA group and 3rd period of the periodic table.
Atomic number of ${\text{Cl}}$= 17
Atomic mass of ${\text{Cl}}$ = 35.45 amu
Atomic mass is the sum of the number of protons and the number of neutrons present in an atom. It is the mass of one atom. As we know that molar mass is the sum of atomic masses. As there are 2 chlorine atoms present in the formula of chlorine gas.
So, ${\text{molar mass of chlorine gas ,C}}{{\text{l}}_{\text{2}}} = 2 \times {\text{atomic mass of Cl = 2}} \times {\text{35}}{\text{.45 g/mol = 70}}{\text{.9 g/mol}}$
As we know the equation related to moles, mass and molar mass is as follows:
${\text{mole = }}\dfrac{{{\text{mass}}}}{{{\text{ molar mass}}}}$
So, for 1 mole of any substance, we can say that
Mass = molar mass
So the mass of 1 mol of chlorine gas, ${\text{C}}{{\text{l}}_{\text{2}}}$ = 70.9g.
Thus, we can say that One mole of chlorine gas is equal to 70.9g

Note: A mole of a substance is the mass of a substance that contains exactly the same number of fundamental units, as in 12.0 g of C. Molar mass of a substance is the summation of masses of all atoms contained in that molecule. Mass of 1 mole of substance is always equal to its molar mass.