1 Dozen Eggs = ________eggs. 1 Ream of Paper = _______ sheets of paper.

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mole and is abbreviated mol. The Mole Scientists needed a unit to bridge between the invisible world of atoms and macroscopic world of materials and objects. This unit is called a mole and is abbreviated mol. A mole is a fundamental SI unit used to measure the amount of a substance.

A mole IS A COLLECTION OF 6.02 x 1023 PARTICLES Particles can include: Atoms Molecules Compounds

Why use the mole? The mole is used because there is exactly 1 mole of atoms in the atomic mass of an element when that mass is expressed in grams. Molar mass for all purposes is the same as the atomic mass. So 1 mole of C-12 , or 6.02 x 1023 atoms, has a mass of 12.00 g.

Who is Avogadro? The number is named after Amedeo Avogadro because his ideas were crucial to the early development of chemistry.

Practice finding molar mass! 1 mole of any element is equivalent to it’s molar mass. H = 1.0079 g = 1 mole O2 = 16.0 x 2 = 32.0 g = 1 mole H2SO4 = 98.1 g = 1 mole

How many moles are in 90.0 g of water? Formula of water: H2O Molar mass of water: 18.0 g = 1 mole Equation: 90.0 g x 1 mole = moles 18 g Answer: 5 moles

How many grams are in 6.1 moles of NaCl? Molar mass: 1 Na x 22.990 g = 1 Cl x 35.453 g = Equation: 6 moles NaCl x 58.443 gNaCl = grams 1 mol NaCl Answer with Sig Figs: 360 grams NaCl

How many grams are in 0.251 moles of HF? Molar mass: 1 H x 1.0079 g = 1 F x 18.988 g = Equation: 0.251 moles HF x 20.0 g HF = grams 1 mol HF Answer with Sig Figs: 5.02 g HF

How many molecules are in 0.25 moles of water? Formula of water: H2O Conversion factors needed: 1 mole H2O = 18 g H2O & 1 mole = 6.02 x 1023 particles Equation: 0.25 moles H2O x 6.02 x 1023 particles = 1 mol H2O Answer with sig figs: 1.5 x 1023 particles H2O

How many moles are in 5.23 x 1020 molecules of MgS? Conversion factor needed: 1 mole = 6.02 x 1023 particles Equation: 5.23 x 1020 part MgS x 1 mole MgS = 6.02 x 1023 part MgS Answer with Sig Figs = 8.69 10-4 mol MgS

How many molecules are in 10.0 g of NF3? Molar mass: 71.0 g Equations: 10.0 g NF3 x 1 mole NF3 x 6.02 x 1023 part NF3 71.0 g NF3 1 mole NF3 Answer with sig figs: 8.48 x 1022 part NF3

How many grams does 1.80 X 1024 molecules of Cu(OH)2 weigh? Molar Mass: 97.56 g Equations: 1.80 X 1024 part Cu(OH)2 x 1 mole Cu(OH)2 x 97.56 g Cu(OH)2 6.02 x 1023 part Cu(OH)2 1 mol Cu(OH)2 Answer with sig figs: 291.7 g Cu(OH)2