Stoichiometry: Mathematics of Chemical Formulas and Equations

How much is…How much is…

a MOLE is just a number pair =

trio = quartet = dozen = baker’s dozen = gross = ream =

23

412 13144500

LOL YOU FUNNY

a MOLE is just a number

A LARGE ONE

6.022x1023

MOLE = Avogadro’s Number

That is….

602,200,000,000,000,000,000,

000

9.12 x 1013

How BIG is a mole?

There are ~ 6.6 billion people on Earth

How many Earths would it take to equal the population of 1 mole?

• If you had a mole of $$$$$ and you spent $800 billion dollars a day how many years would it take to spend a MOLEion dollars?

2.06 x 109 years

If you had a mole of H2O could you swim in it?

NO!Water molecules are so small

that a mole of H2O = 18ml

How small are atoms?• There are more atoms in one gram of salt

than grains of sand on all the beaches of all the oceans in all the world.

• Each time you take a breath of air, you inhale about 2 x 1022 molecules of nitrogen and 5 x 1021 molecules of oxygen.

• In chemistry we don’t work with individual atoms or molecules because they are too small to be weighed or measured

• We have to work with LOTS of atoms in order to measure them

THAT’s WHERE THE

MOLE COMES IN!

The Mole = Avogadro’s Number

•Definition: a chemical mass unit, defined to be 6.022 x 1023 molecules , atoms, or formula units .The mass of a mole is the molar mass of a substance.

(UNITS = g/mol)

Representative Particles

The smallest pieces of a substance:1) For a covalent compound: it is the

molecule.2) For an ionic compound: it is the

formula unit (made of ions).3) For an element: it is the atom.

• Remember the diatomic elements!

Hello Ladies here is my number…..6.02x1023

Avogadro’s Number is named in honor of the Italian chemist Amadeo Avogadro (1776-1855)…though he didn’t discover it.

Avogadro’s Number

<-----Jean Perrin

Avogadro's law

States that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules

Atomic Mass

•mass in grams of 1 mole of atoms of an element

• In other words……

1 mol C atoms = 6.02 x 10 23 C atoms = 12g C

check the periodic table yo!

Practice

Remember . . .1 mole = 6.02x1023 atoms or

molecules = ______ g from the periodic table

Practice How many molecules of CO2

are in 4.56 moles of CO2?

How many moles of water is 5.87 x 1022 molecules?

Practice How many molecules of CO2

are in 4.56 moles of CO2?

How many moles of water is 5.87 x 1022 molecules?

2.75 x 1024 molecules

0.0975 mol or (9.75 x 10-2)

Practice problems How many atoms of carbon

are in 1.23 moles of C6H12O6?

How many moles is 7.78 x 1024 formula units of MgCl2?

4.44 x 1024 atoms C

12.9 moles

Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di

Cerreto

Thank you