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MOLAR MASS CALCULATIONS I. TO DETERMINE MASS OF SPECIFIC ELEMENT AND TOTAL MASS OF A COMPOUND Make a list of each element and the number of atoms of each element present in the compound. Using the periodic table, determine the mass for each element (round to a whole number, easier for your calculations). Multiply each mass by the number of atoms in the formula. Add up the results to get the total molar mass for the entire compound. Example: H2SO4 1. H = 2 S=1 O=4 2. H = 1g S = 32g O = 16g 3. H = 2 * 1g = 2g S = 1 * 32g = 32g O = 4 * 16g = 64g 4. 2g + 32g + 64g = 98g Complete these: H2O, NH3, C2H4O2, K2Cr2O7 II. PROBLEMS INVOLVING MOLES 45 moles of H2O = ? grams of H2O Determine specific amount (mass) of each element Find total mass of compound Using fence method, convert moles to grams III. PROBLEMS INVOLVING ATOMS 9.4 x 1035 atoms of AmO = ? grams AmO Determine specific amount (mass) of each element Find total mass of compound Using fence method, convert atoms to moles, then moles to grams Recall 6.02 x 1023 atoms = 1 mole (no matter the substance, element, compound)