Density and Moles!

Density is a measure of mass per volume represented by this formula! The units are interchangeable, so if you need to figure out mass or volume, you can rearrange and solve!

Density is measured in g/l or g/ml.

Today we also learned about the density of Gases. They vary with temperature. The formula for finding the density of a gas is mm(molar mass)/ stp(22.4l)

Atoms-Molecules-Moles

Moles
^
Molecules(chemical formula of an element)
^
Atoms(what matter is made up of)

Awhile back, we learned how to go from atoms to molecules to moles. It's hard to explain, so let's do an example.


How many atoms are there in 1.5mol of Iron?
So first off, we write down what we know.

1.5Mol

You want to cancel moles, so you put moles on the bottom, and since you want atoms, you put atoms on top. Remember 1atom is equal to avogadro's number which is 6.02x10^23.

1.5mol x 6.02x10^23/1mol which equals 9.03x10^23 atoms, remember significant digits! = 9.0x10^23 atoms!

What's the difference between atoms and Molecules?
Molecules are composed of atoms, for example Lithium's atomic mass is 6.9.If an element is diatomic such as Carbon, it is 12x2.
(HOFBRCl)