Mole to Atom/Molecule conversions

Today we learned how to convert from moles to atoms or from moles to molecules
Pretty basic stuff if I do say so myself!

1. FROM MOLES TO ATOMS:

Determine the number of atoms that are in 1.25 mol of O2


1.25mol x 6.02x10^23 atoms/ 1 mol = (7.53 x 10^23)
But since we're looking for Oxygen gas (diatomic) we times our answer by 2.
= (7.53 x 10^23) x 2
= 1.51 x 10^24 atoms

Determine the number of atoms that are in 0.58 mol of Se
0.58 mol x 6.02 x 10^23 atoms/ 1 mol = 3.5 x 10^23 atoms

2. FROM ATOMS TO MOLES


How many moles are present in 3.9 x10^25 Nitrogen atoms?

3.9x10^ 25 Nitrogen atoms x 1 mol/6.02x10^23 atoms= 64.8 moles


A cylinder of Helium contains 4.6 x 10^30 atoms. How many moles of Helium is this?


4.6 x 10^30 atoms x 1 mol/ 6.02 x 10^23 atoms = 7.6 x 10^6 mol
                                          

Are you slowly realizing that conversions aren't at all that difficult like this fellow right here?
GOOD lets try another one, but this time even more complicated!


How many water molecules are there in 0.65 mol? How many hydrogen atoms are there? How many oxygen atoms are there?

If your initial reaction looks something like this^..... than follow the steps below!


First step: Do not panic after reading this question! Lets take it STEP BY STEP!


Let us first find how many water molecules is in 0.65 moles


0.65 mol x 6.02 x 10^ 23 molecules / 1 mol
You are trying to find molecules/atoms so put that on top!


Cancel out units of moles and times 0.65 and 6.02 x 10^23 and you will get 


3.9 x 10 ^ 23 molecules
How many hydrogen atoms are there?


Remember they are asking for water molecules, and the chemical equation for water is H20
In this equation we see 2 Hydrogen atoms so...


(3.9x10^23atoms) x 2 = 7.8 x 10^23 atoms of Hydrogen


How many oxygen atoms? There is no subscript next to Oxygen so we assume its 1
(3.9x10^23atoms) x 1= 3.9 x 10^23 atoms of oxygen


Yay! You did it!


Post by Ren Flores