The Mole

•Atoms & molecules are extremely small

•The number of individual particles in even a small sample of something is very large

•Therefore, counting the number of particles is not a practical way to measure the sample.

The Mole

•A chemical counting unit (abbreviated “mol”)

•Similar to a dozen, except instead of 12, it’s 602 billion trillion 602,000,000,000,000,000,000,000

•6.02 X 1023 (in scientific notation)

The Mole

6.02 X 1023

• This number is named in honor of Amedeo AvogadroAmedeo Avogadro, who studied quantities of gases and discovered that no matter what the gas was, there were the same number of molecules present in a constant volume of gas.

The MoleThat’s

my number

!

•The term representative particle refers to the species present in a substance–Usually atoms or molecules

The Mole

Using Avogadro’s Number

6.02 x 1023Use my

number, I’m waiting...

What number of moles of Mg is equivalent to 1.806 x 1024 atoms of Mg?

What number of moles of Mg is equivalent to 1.806 x 1024 atoms of Mg?

*Remember*1 mol Mg = 6.02x1023

atoms Mg

*Remember*1 mol Mg = 6.02x1023

atoms Mg

6.02x1023 atoms Mg

6.02x1023 atoms Mg

1 mol Mg1 mol Mg1.806x1024 atoms Mg1.806x1024 atoms Mg

= 3.0 = 3.0 molesmoles= 3.0 = 3.0 molesmoles

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How many of moles of C2H6 is 9.17 x 1023 molecules of C2H6?How many of moles of C2H6 is 9.17 x 1023 molecules of C2H6?

1 mol C2H6 = 6.02x1023 molecules C2H6

1 mol C2H6 = 6.02x1023 molecules C2H6

6.02x1023 molecules C2H6

6.02x1023 molecules C2H6

1 mol C2H61 mol C2H69.17x1023

molecules C2H6

9.17x1023 molecules C2H6

= 1.52 = 1.52 molesmoles= 1.52 = 1.52 molesmoles

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If we had 2.5 moles of sugar, how many molecules of sugar is that equal to?

If we had 2.5 moles of sugar, how many molecules of sugar is that equal to?

*Remember*1 mol sugar = 6.02x1023

molecules sugar

*Remember*1 mol sugar = 6.02x1023

molecules sugar

6.02x1023 molecules sugar

6.02x1023 molecules sugar1 mol sugar1 mol sugar

2.5 mol sugar

2.5 mol sugar

= 1.51x10= 1.51x102424 molecules molecules of sugarof sugar

= 1.51x10= 1.51x102424 molecules molecules of sugarof sugar

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How many atoms of gold are in 0.75 moles of gold?

How many atoms of gold are in 0.75 moles of gold?

1 mol gold = 6.02x1023 atoms gold

1 mol gold = 6.02x1023 atoms gold

6.02x1023 atoms gold

6.02x1023 atoms gold1 mol gold1 mol gold

0.75 mol gold

0.75 mol gold

= 4.52x10= 4.52x102323 atoms atoms of goldof gold

= 4.52x10= 4.52x102323 atoms atoms of goldof gold

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