Unit 2: Atomic Theory & Structure Molar Mass Conversions

Molar Mass Atoms are so small that we work with billions of them at a time in the laboratory. We can’t count them out individually, but we can count them by weighing.

mass of one mole of particles Molar Mass: mass of one mole of particles units: grams per mole (g/mol) 6.02 x 1023 particles 1 mole

Periodic Table 55.85g 12.01g One molar mass of carbon, sulfur, mercury, and iron are shown. Each of the quantities contains one mole of the element. Applying Concepts How many atoms of each element are shown? 32.07g 200.59g

Use molar mass as a conversion factor to convert between mass and moles. (get MM from the PT) Type 3 mol grams Given mol x MM of given = ______g 1 mol Type 4 grams mol given g x 1 mol = _____ mol MM (g)

Type 3 mol grams What is the mass of 9.45 mol of aluminum, Al? 9.45 mol x 26.98g _______ = 1 mol 255 g

Find the mass, in grams, of 0.0452 mol C20H42 (wax). Type 3 mol grams Find the mass, in grams, of 0.0452 mol C20H42 (wax). (MM = 282.62 g/mol) 0.0452 mol x 282.62 g _______ = 1 mol 12.8 g

How many moles are in 92.2 g of Fe2O3 ? Type 4 grams mol When iron is exposed to air, it corrodes to form red-brown rust which is iron(III) oxide (Fe2O3). How many moles are in 92.2 g of Fe2O3 ? MM = 159.70 g/mol 92.2 g x ______= 159.70 g 1 mol 0.577 mol Rust weakens an iron chain.

Find the number of moles in 258 g N2O. Type 4 grams mol Find the number of moles in 258 g N2O. MM = 44.02 g/mol 258 g x ______= 44.02 g 1 mol 5.86 mol

1. Where do you look to get the molar mass of an element? Quick Quiz! 1. Where do you look to get the molar mass of an element? Avogadro’s number the periodic table your neighbor’s paper your face

Quick Quiz. 2. Calculate the mass in grams of a sample containing 1.85 mol of water. 1.11 x 1024 g 33.3 g 18.02 g 8460 g MM = 18.02 g/mol

Quick Quiz. 3. Calculate the number of moles in a spoonful of table salt (NaCl) having a mass of 3.50 g. 208 mol 2.58  103 mol 0.0599 mol 17.0 mol MM = 58.44 g/mol