What is a Mole How many socks come in a pair? 2 How many eggs are in a dozen? 12 How many eggs come in a gross? 144 How many pencils come in a ream? 500 So how many things come in a mole? Conversion Review Dimensional Analysis Example Problems Relative Mass Molar Mass Using molar mass Converting between mass and atoms Chemical Formulas and the Mole Molar Mass of a Compound Determine the molar mass of each of the following compounds: NaOH CaCl2 KC2H3O2 C2H5OH HCN CCl4 (NH4)3PO4 Converting moles to mass The characteristic odor of garlic is due to the compound (C3H5)2S. What is the mass of 2.5 moles of (C3H5)2S? What is the mass of 3.25 mol of H2SO4? Converting Mass to Moles Calculate the number of moles in 325 g of Calcium hydroxide Ca(OH)2? Calculate the number of moles in 22.6 g of AgNO3. Mass to Number of Particles How many Aluminum Chloride molecules are present in 35.6 g of AlCl3 How many Al atoms are there? How many Cl atoms are there? Example Aluminum oxide (Al2O3) when dissolved in water breaks apart into ions (Al3+ and O2-) how many moles of Al3+ will be produced when 1.5 moles of Al2O3 are dissolved in water? Examples What is the molar mass of ethanol C2H5OH? 1. How many ethanol molecules are present in 45.6 g? How many carbon atoms are there in 45.6 g of ethanol? How many hydrogen atoms are there in 45.6 g of ethanol? How many oxygen atoms are there in 45.6 g of ethanol? A sample of sodium sulfite Na2SO3 has a mass of 2.25 g 2. How many molecules of sodium sulfite are there? How many atoms of sodium are there? How many atoms of Sulfur are there? How many atoms of oxygen are there? Percent Composition The molar mass of NaOH is Na – 22.98 g/mol O – 16 g/mol H – 1 g/mol Total: 39.98 g/mol Example NaHCO3 Empirical Formula Example Find the empirical formula for hydrogen peroxide which has a molar mass of 34 g/mol and is 5.9% Hydrogen and 94.1% Oxygen Molecular Formula Example Example Find the empirical and molecular formula for a compound that is 26.5% K, 35.4% Cr, and 38.1% O and has a molar mass of 294.2 g/mol. Example Find the empirical and molecular formula for a compound that is 26.7% carbon, 2.2% hydrogen, and 71.1% oxygen and has a molar mass of 90 g/mol.