Question

How do you find the molar mass of sulfur hexafluoride?

Answer 1

Hint: Sulfur hexafluoride is a compound and it is made up of two elements i.e., sulfur and fluorine. First, multiply the number of atoms of an element to the atomic mass of the element and then add the masses.

Complete answer:
We know that every element has a different atomic number and different atomic mass. If we consider only one element having one atom then the atomic mass term is used. But for elements that have more than one atom or compounds having different elements, molecular mass or molar mass is used.
Sulfur hexafluoride is a compound and made up of two elements i.e., sulfur and fluorine. So, its formula is $S{F}_6$, therefore, we can see that there are one sulfur atom and six fluorine atoms.
To calculate the molar mass, first, multiply the number of atoms of an element by the atomic mass of the element and then add the masses.
The exact atomic mass of sulfur is 32.066 gm. There is only one sulfur atom so, the mass of sulfur in Sulfur hexafluoride will be 32.066 gm.
The exact atomic mass of fluorine is 18.998 gm. There are six fluorine atoms so, we have to multiply it with six, we get:
$18.998\text{ x 6 = 113}\text{.988 gm}$
Now, adding both the masses, we get:
$32.066\text{ + 113}\text{.988 = 146}\text{.054 gm}$
So, the molar mass of Sulfur hexafluoride will be 146.054 gm.

Note:
If you don’t remember the exact mass of the element then you can take the round-off mass also like for sulfur the mass can be taken as 32 and the mass of fluorine can be taken as 19.