The Mole Avogadro’s number

The Mole How much is: A dozen? 12 A century? 100 A mole? 6.02 x 1023 (602,000,000,000,000,000,000,000)

Units of Measurement Dozen = 12 things Bakers dozen= 13 things Pair= 2 things Decade = 10 years Gross = 144 things Ream = 100 things I Mole = 6.02 x 1023 things

1Mole = 6.02 x 1023 This is a huge number! How long would it take to spend a mole of pennies …. at a $million /second?

Can you spend a mole of dollars? If you could spend $1,000,000 every second it would take you 6.02 x 10 23 ÷ $1,000,000/sec ÷ 60 sec/min ÷ 60 min/hr ÷ 24hrs/day ÷ 365 days/yr = 19,000,000,000 years! If you started spending at the big bang you would be finished in 6 billion years.

Since we can’t count a mole of atoms, we MUST mass chemicals to measure moles 6.02 x 10 23 atoms of sulfur 32.07 grams of sulfur 6.02 x 10 23 atoms of carbon 12.01 grams of carbon

Why use this value? It makes conversions to mass easy since one mole of protons has a mass of one gram! The molar mass (mass of one mole) of a substance is the same value as the formula mass but in grams instead of amu.

Conversions with Moles How do you find mass of one mole of substance? We can do this if we know the formula mass When we do this we get the MOLAR MASS The mass in grams of 1 mole of substance is equal to the formula mass Units: grams/mol

Molar Mass Examples carbon aluminum zinc 12.01 g/mol 26.98 g/mol

How do we measure moles? The atomic mass (in amu) on your periodic table is the mass of a mole of atoms of that element (in grams.) What is the mass of a mole of copper atoms? So, to count 6.02 x 1023 copper atoms, we mass out 63.55 g on the scale.

Molar Mass Examples water sodium chloride H2O 2(1.01) + 16.00 = 18.02 g/mol NaCl 22.99 + 35.45 = 58.44 g/mol

Find the molar mass of: Ammonium phosphate NH4+ PO43- (NH4)3PO4 =42 +12 +31 +64 =149g Carbon dioxide CO2 = 12 + 32 = 44 g

Molar Mass Examples sodium bicarbonate sucrose NaHCO3 22.99 + 1.01 + 12.01 + 3(16.00) = 84.01 g/mol C12H22O11 12(12.01) + 22(1.01) + 11(16.00) = 342.34 g/mol

Measuring with Moles The Mole is a counting unit Called the chemist’s dozen Used to count number of Atoms Molecules We will count both atoms and molecules

Super Mole Highway So Far we Can Convert Between Moles Grams Particles The Mole Highway will help us convert from one to another

Super Mole Highway Divide by molar mass Multiply by 6.02  1023 MOLES IN GRAMS MOLES NUMBER OF PARTICLES Multipy by molar mass Divide by 6.02  1023

Find the mass of: A mole of silicon atoms 6.02 x 1023 atoms of nitrogen 6.02 x 1023 atoms of sodium 2 moles of sodium atoms

Find the mass of: A mole of silicon atoms 28.09 g 6.02 x 1023 atoms of nitrogen 14.01 g 6.02 x 1023 atoms of sodium 22.99g 2 moles of sodium atoms 45.98 g

How many atoms are in: A mole of silicon 14.01 g of nitrogen 2 moles of sodium 45.98 g of sodium

How many things are in: A mole of footballs A mole of water 2 moles of pencils ½ mole of lead