When you have a dozen of something, no matter what you are talking about, you have 12 of that thing. -A dozen donuts - a dozen eggs -a dozen cars, -a dozen chemistry problems are all 12 of that material.
The mole is the exact same concept. You can have: -a mole of eggs - a mole of donuts - a mole of cars - a mole of chemistry problems. However a mole is MUCH bigger than 12...it is 602 sextillion. Obviously a mole of chemistry problems is way too many problems.
The mole is typically used for counting or grouping very very small things, like atoms
a MOLE ( mol ) 1. The mole is an SI unit that allows us to count # of: -Atoms - molecules -formula units without actually seeing them Representative particles
2. 1 mol = 6.02 x 10 23 representative particles 3. The number is called Avogadros number in honor of the Italian scientist Amadeo Avogadro
Avogadros number Atoms or Molecules or FUNs 1 mole of anything = 6.02 x 10 23
4. REPRESENTETIVE particles: 1.ATOMs (elements on the PT) 2. MOLECULES (_______compounds – all elements are non metals) EX: CO 2, NO 2, C 12 H 22 O 11 3. Formula Units (_____compounds – at least one element must be a metal) EX: NaCl, CuCl 2, FeO covalent ionic
A DOZEN MASS of a dozen limes = MASS of a dozen cars
A MOLE CARBON COPPER MASS of a mole carbon = MASS of a mole copper 6.02 x 10 23 C atoms = 6.02 x10 23 Cu atoms
MOLAR MASS – the mass of 1 mole of any pure substance (element and compound) Molar Mass (MM) = Atomic mass (AM) MM units - g/mol AM - Atomic Mass units - amu ( atomic mass units) EX: Mn - 54.94 amu = 54.94 g/mol
EXAMPLES: 1.1 mole of Al : 2. 1 mole of CO 2 : AM (C) = 12.011 amu = MM # of atoms = # of moles AM (O) = 16.00 amu x 2 = MM 12.011 + 2 (16.00) = 44.01 g/mole AM 26.98 g =MM 26.98 g/mol
3. 1 mole of Cu(NO 2 ) 2 : AM (Cu) 63.546 amu = MM g/mole AM (N) 14 x 2 amu = MM g/mole AM (O) 16 x 4 amu = MM g/mole 63.546 + 2(14) + 4 (16) =155.5 g/mole