Bling Bling: if I were to give each of you one atom of gold for every second that has elapsed since the Dinosaur’s went extinct 65 million years ago, how much gold would you have?

Moles Not to be confused with this very happy individual. In Chemistry a mole is defined as 6.022x1023 particles of a substance.

How many eggs are in a dozen? How many apples are there in a dozen? If a dozen students get detention, how many students have detention? Dozen = 12 units

Moles 6.022 x 1023 is known as Avogadro’s number. Just as a dozen of any substance equals 12 units of that substance, a mole of any substance equals 6.022 x 1023 units of that substance. Avogadro came up with the idea that equal volumes of different gases as STP have the same number of particles….this led to scientists coming up with a more precise number… Avogadro’s Number (symbol N) is the number of atoms in 12.01 grams of carbon. We determine a mole using electric charge (among other means). If we know the charge of one electron and the total charge of one mole of a substance very accurately, we can calculate the number of electrons in a mole of electrons. Avogadro’s number is a MEASURED number.

Avogadro’s number is a MEASURED number. Avogadro: equal volumes of different gases at STP have the same number of particles Avogadro’s Number is the number of atoms in 12.01 grams of carbon. If we know the charge of one electron and the total charge of one mole of a substance very accurately, we can calculate the number of electrons in a mole of electrons.

Fe MOLAR MASS The atomic mass of iron is 55.85 AMUs. 1s22s22p63s23p64s23d6 26 Fe IRON 55.85 The atomic mass of iron is 55.85 AMUs. This number also represents the molar mass of Iron. Iron has a mass of 55.85 grams per mole.

Fe MOLAR MASS This is the molar mass of any single element Unit: g/mol 1s22s22p63s23p64s23d6 26 Fe IRON 55.85 This is the molar mass of any single element Unit: g/mol

What is the molar mass of Gold Mercury Argon Oxygen Sulfur Hydrogen

What is the molar mass of Gold Mercury Argon Oxygen Sulfur Hydrogen 197g/mol 200.6g/mol 39.95g/mol 32g/mol (diatomic) 32.07g/mol 2g/m (diatomic)

Au Ag Concept Check How many atoms are there in a mole of gold atoms? How many atoms are there in a mole of silver atoms? 79 Au Gold 197 47 Ag Silver 107.9

Au Ag Concept Check 1 mol = 6.022 x1023 units How many atoms are there in a mole of gold atoms? How many atoms are there in a mole of silver atoms? 79 Au Gold 197 47 Ag Silver 107.9 1 mol = 6.022 x1023 units

Give me One Mole of Iron If I asked you for one mole of iron, how would you do it?

Weigh out 55.85g of iron How many atoms of iron would you be giving me? A mol is defined as 6.022 x 1023 particles 26 Fe IRON 55.85

Give me 3.63 moles of iron? If I asked you for 3.63 moles of iron, how would you do it?

The same way you would give me 4 dozen of something By Using Conversion Factors

Converting 3.63 Moles Fe to grams

How many moles is 512 grams of iron? We solve this again using conversion factors and the molar mass of iron.

Converting 512g Fe to moles.

How many atoms are in 9.17mol Fe?

How many moles are in 25 x 1024 atoms of Fe?

Mole Worksheets 1, 2

Compounds have Molar Mass 1g/mol 16g/mol 1g/mol + 1g/mol + 16g/mol = 18g/mol

Table Salt NaCl Na+ Cl- 23g/mol 35.5g/mol 23g/mol + 35.5g/mol =58.5g/mol

12(12g/mol) + 22(1g/mol) + 11(16g/mol) = 342.3g/mol Molar Mass of Sucrose C12H22O11 C H O 12(12g/mol) 22(1g/mol) 11(16g/mol) 12(12g/mol) + 22(1g/mol) + 11(16g/mol) = 342.3g/mol

Molar Mass of Magnesium Nitrate Mg(NO3)2 Mg N O 24.3g/mol 2(14.01g/mol) 6(16g/mol) 24.3g/mol + 2(14.01g/mol) + 6(16g/mol) = 148.3g/mol

Mole worksheet 3

Molecular Mass Molar mass is for the average atomic mass but molecular is for a single molecule but atoms come in different isotopes….

How many moles is 512g of water? Convert 512g H20 ---> moles

We can Convert Molecules Convert 7.5mol H20 ---> grams

Rust weakens an iron chain.

These aluminum satellite dishes at the National Radio Astronomy Observatory near Soccoro, New Mexico are naturally protected from corrosion by the formation of a thin film of aluminum oxide (Al2O3).

Activity: 1 Cup of Water ~236ml How many grams is it? What is its molecular mass? How many moles is it? How many molecules of H2O are there? How many total atoms? All you need for this is a periodic table and a calculator

Worksheet 4

Moles and Volume at STP STP = Standard Temperature and Pressure TEMPERATURE: 273.15 K (0 °C, 32 °F) PRESSURE: 100 kPa (14.504 psi, 0.987 atm, 1 bar). Remember: volume is proportional to temperature!

Calculating Gas Density What is the density of ammonia gas, NH3, at STP? First we need the molar mass for ammonia; 14.01 + 3(1.01) = 17.04 g/mol The molar volume NH3 at STP is 22.4 L/mol. Density is mass/volume: = 0.761 g/L 17.04 g/mol 22.4 L/mol

Calculating Gas Density What is the density of, O2, at STP? First we need the molar mass for O2; 2(16g/mol) = 32 g/mol The molar volume O2 at STP is 22.4 L/mol. Density is mass/volume: = 1.4 g/L 32 g/mol 22.4 L/mol

Calculating Gas Volume What is the Volume of 5 moles of He at STP? First we need the molar mass for He; He = 4 g/mol The molar volume of He at STP is 22.4 L/mol.

Calculating Moles From Volume How many moles is 5 Liters of N2 gas at STP? The molar volume of N2 at STP is 22.4 L/mol.

Molar Mass of a Gas We can also use molar volume to calculate the molar mass of an unknown gas. 1.96 g of an unknown gas occupies 1.00L at STP. What is the molar mass? We want g/mol, we have g/L. 1.96 g 1.00 L 22.4 L 1 mole × = 43.9 g/mol

Mole Unit Factors We now have three interpretations for the mole: 1 mol = 6.02 × 1023 particles 1 mol = molar mass 1 mol = 22.4 L at STP for a gas This gives us 3 unit factors to use to convert between moles, particles, mass, and volume.

Mole-Volume Calculation A sample of methane, CH4, occupies 4.50 L at STP. How many moles of methane are present? We want moles, we have volume. Use molar volume of a gas: 1 mol = 22.4 L 4.50 L CH4 × = 0.201 mol CH4 1 mol CH4 22.4 L CH4

Mass-Volume Calculation What is the mass of 3.36 L of ozone gas, O3, at STP? We want mass O3, we have 3.36 L O3. Convert volume to moles then moles to mass: 3.36 L O3 × × 22.4 L O3 1 mol O3 48.00 g O3 = 7.20 g O3

Molecule-Volume Calculation How many molecules of hydrogen gas, H2, occupy 0.500 L at STP? We want molecules H2, we have 0.500 L H2. Convert volume to moles and then moles to molecules: 0.500 L H2 × 1 mol H2 22.4 L H2 6.02×1023 molecules H2 1 mole H2 × = 1.34 × 1022 molecules H2

Conclusions Avogadro’s number is 6.02 × 1023 and is one mole of any substance. The molar mass of a substance is the sum of the atomic masses of each element in the formula. At STP, 1 mole of any gas occupies 22.4 L.

Conclusions Continued We can use the following flow chart for mole calculations:

Bling Bling: if I were to give each of you one atom of gold for every second that has elapsed since the Dinosaur’s went extinct 65 million years ago, how much gold would you have?