2What is Avogadro’s Number? What is a mole?The SI unit that represents the amount of a substance that contains 6.02 x 1023 representative particles of that substance.What is Avogadro’s Number?The number of particles contained in one mole of a substance.6.02 x 1023 particles602,000,000,000,000,000,000,000
3What is a Representative Particle? Atom:The smallest particle of an elementMolecule:Group of atoms joined together by covalent bondsFormula unit:Lowest ratio of elements in ionic bondsParticle:This word can be used for any of the above words
4Atomic or Formula MassMass of one single representative particle of a substanceMeasured in atomic mass units (amu)
5C 12.01 amu NaCl 22.99 amu + 35.45 amu = 58.44 amu H2O How do you find Atomic or Formula Mass?Add up the amu for every part of the substance:Find the amu on the Periodic TableC12.01 amuNaCl22.99 amu amu = amuH2O(1.01 amu x 2) amu =18.02 amu
6Molar Mass C 12.01 amu = 12.01 g/mol NaCl 58.44 amu = 58.44 g/mol H2O The mass of one mole of any substanceMeasured in grams/ moleSame as finding atomic mass, but change amu to grams.C12.01 amu = g/molNaCl58.44 amu = g/molH2O18.02 amu = g/mol
7Converting # of Particles to # of Moles Formula:1 mole6.02 x 1023 particles# of moles =# of particles x
8Sample Problem:How many moles of NaCl are in 3.01x1023 formula units of NaCl?
9Converting # of Moles to # of Particles Formula:6.02 x 1023 particles1 mole# of particles =# of moles x
10Sample Problem:How many particles are in 3 moles of water?
11Converting # of Moles to Mass Formula:Molar mass (g)1 moleMass (g) =# of moles x
12Sample Problem:What is the mass of 1 mole of LiOH?
13Converting Mass to # of Moles Formula:1 moleMass (g)# of moles =Mass (g) x
14Sample Problem:How many moles of NaCl are in grams of NaCl?
15Mole-Volume Relationship Avogadro’s Hypothesis:At standard temperature and pressure (STP) 1 mole of any gas occupies the same volume.STP: 0oC and 1 atm
16At STP, 1 mole or 6.02 x 1023 particles, of ANY gas, has a volume of 22.4 L. 22.4 L is called the molar volume of a gas.
17Converting # of Moles of gas to Volume Formula:22.4 L1 moleVolume of gas =moles of gas x
18Sample Problem:What is the volume, in liters, of 0.60 mol of SO2 gas at STP?
19Converting Volume of gas to Moles Formula:1 mole22.4 LMoles of gas =volume of gas x
20Sample Problem:If you collect 8.00 L of O2 gas, how many moles have you collected?
21Calculating Molar Mass from Density Formula:gramsmolegramsL22.4 L1 mole=DensityMolar mass
22Sample Problem:What is molar mass of a gas with a density of 2.86 g/L at STP?
23Percent Composition of a Substance Mass of element in the compound xMolar Mass of Compound
24Sample Problem Find the % composition of H and O in water