Introduction to the mole

Introduction to the Mole (the science one)

And some practice problems

The Video below is a review of what we did in class on Wednesday January 8th. You don't have to watch it, but it may help if you get stuck.
(It is also on Google Classroom if you need it).

The Mole is a quantity

Just like the saying "a dozen" refers to a specific number of something (12), saying "a mole" refers to a certain number of a thing.


A mole of a thing is equal to Avogadro's number of that thing.

Avogadro's number

"Avogadro's number" is the specific name we give to the number
6.02214076 x 10²³

Multiple Choice

Based on the information on the last few slides, how many blueberries would be in 1 mole of blueberries?

• 6.02214076 x 10²³

• 12

• 600000

• you can't use moles to measure blueberries! That would be like using a scale to measure volume.

​Hopefully it is obvious we use moles to measure very tiny things.

Specifically, atoms and molecules. The reason that moles are helpful is because
1 mole of a specific substance weighs the same amount in grams as 1 molecule that substance weighs in atomic mass units (amu)

How to figure out the weight of a molecule:

First you figure out the number of each type of atom in the molecule, then multiply the number of each atom by the weight of the atom (based on the periodic table) and finally add all those together.

(I show you how in the video at the beginning and on Google Classroom)

Dropdown

Sodium Hydroxide has a chemical formula of NaOH. Based on this, sodium hydroxide is made up of ​

Select answer

sodium atom, ​

Select answer

oxygen atom, and ​

Select answer

hydrogen atom.

Fill in the Blanks

amu to grams

Since 1 molecule of NaOH weighs 40 amu, 1 mole of NaOH weighs 40 grams!

See how convenient that is!



Now for some practice!

Fill in the Blanks

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Multiple Choice

Which weighs more, one gram of water or one gram of carbon dioxide?

• the water

• the carbon dioxide

• they both weigh the same

Multiple Choice

Which weighs more, one milliliter of water or one milliliter of carbon dioxide?

• the water

• the carbon dioxide

• they both weigh the same

Multiple Choice

Which weighs more, one mole of water or one mole of carbon dioxide?

• the water

• the carbon dioxide

• they both weigh the same