Empirical & Molecular Formulas PDF

Empirical & Molecular Formulas CHEM 1211  Empirical Formula Shows the elements which make up a compound with subscripts that tell the number of each type of atom in the lowest whole number ratio. It may not be the actual formula for a molecule. Empirical Formula Step 1: percent to ma...

Empirical & Molecular Formulas CHEM 1211  Empirical Formula Shows the elements which make up a compound with subscripts that tell the number of each type of atom in the lowest whole number ratio. It may not be the actual formula for a molecule. Empirical Formula Step 1: percent to mass Step 2: Mass to moles Step 3: Divide by smallest Step 4: Multiply until whole numbers Empirical Formula Calculate the empirical formula from the percentage composition of a compound: %Cu= 33.88% %N= 14.94% %O= 51.18%  Molecular Formula Benzopyrene has a molar mass of 252 g/mol and an empirical formula of C5H3. What is the molecular formula? Molecular Formula You have a sample of a white solid. Analysis shows that it is 40.0% carbon, 6.7% hydrogen, 53.3% oxygen. What is the empirical formula and the molecular formula? The molar mass is 180. grams. Combustion Analysis Burn known mass of compound & weigh amounts of product formed – Generally used for organic compounds (C, H, O) 1) All original C forms CO2 2) All original H forms H2O 3) Original O is found by subtraction Combustion of 0.8233 g of a compound containing only C, H, and O produced the following: CO2 = 2.445 g H2O = 0.6003 g Determine the empirical formula of the compound. Combustion Analysis The smell of dirty gym socks is caused by the compound caproic acid. Combustion of 0.844 g of caproic acid produced 0.784 g of H2O and 1.92 g of CO2. If the molar mass of caproic acid is 116.2 g/mol, what is the molecular formula of caproic acid?