Aim: What is the Mole? Do Now: Answer should be in the correct number of significant figures × × (1.247 × 10 –3 ) ÷ (2.9 × 10 –2 ) × × (2.6 × 10 5 ) (9.2 × 10 –13 )

Counting large numbers… Easier when you use counting units: Dozen Ream Pair Gross Regardless of the object, the number that the units represents is always the same

Atoms and molecules are extremely small, making it impossible actually count them (even in the smallest of samples) Chemists need a unit for counting accurately the # of atoms, molecules, or formula units; they use the mole Mole (mol) = the SI base unit used to measure the amount of a substance 1 mole of anything contains 6.02 x representative particles

1 mole of apples = 6.02 x apples 1 mole of diamonds = 6.02 x diamonds 1 mole of baseballs = 6.02 x baseballs 1 mole of carbon atoms = 6.02 x carbon atoms

The same applies to moles of compounds How many molecules are in 1 mol NH 3 ? 6.02 x NH 3 molecules How many molecules are in 1 mol C 9 H 8 O 4 ? 6.02 x C 9 H 8 O 4 molecules

What is Avogadro’s Number 6.02 X representative particles/mol 1 mol of any substance has 6.02 X representative particles

What are representative particles? Representative particles refers to the species present in a substance: usually atoms, molecules, or formula units

Converting Particles to Moles How many roses are in 3 ½ dozen? USE CONVERSION FACTORS!!! 3.5 dozen x 12 roses =42 roses 1 dozen conversion factor How many pencils are in 6 gross? 6 gross x 144 pencils =864 pencils 1 gross conversion factor

Conversion factor A conversion factor is used to convert a measured quantity to a different unit of measure without changing the relative amount. To accomplish this, a ratio (fraction) is established that equals one (1)

Converting Number of Particles to Mole Conversion factor

Converting number of atoms to moles Units you want are on top These units cancel out 0.465

Converting Moles to Particles and Particles to Moles How many moles contain 4.50 x atoms of zinc? 4.50 x atoms Zn x 1 mol zinc 6.02 x atoms Zn 7.48 mol Zn

Solve How many moles of magnesium is 1.25 X atoms of magnesium?

Converting moles to number of particles Conversion factor

Converting Moles to Particles How many atoms can be found in 3.91 moles of xenon?

Converting Moles to Particles How many particles of sucrose are in 3.50 moles of sucrose? 3.50 mol sucrose x 6.02 x rep. part. 1mol 2.11 x particles of sucrose

Solve How many cadmium atoms are there in 6.57 × 10 3 moles?

2. How many molecules are in 2.00 moles of H2O? Conv. Factor(s) Set-Up 3. How many atoms are in 2.00 moles of H2O? Conv. Factor(s) Set-Up

How many moles are in 6.02 x 1023 atoms of carbon? Conv. Factor(s) Set-Up 10. If you have mole of H2CO3, how many molecules do you have? Conv. Factor(s) Set-Up