CHEM-UA 125 Chapter Notes - Chapter 3.1: Chemical Formula, Molar Mass, Formula Unit

• School: New York University
• Department: Chemistry
• Course: CHEM-UA 125
• Professor: Margaret Mandziuk

Document Summary

General chemistry chapter 3: molecular elements: you must know the formula to determine the molar mass. Mass percent: determining mass percent from a chemical formula. To find the mass of each element in the compound you need to find the composition of a compound in terms of mass percent. Each element contributes a fraction of a compound"s mass and that fraction multiplied by 100 gives the element"s mass percent. For a molecule of compound of compound you have to use the formula mass and chemical formula to find the mass percent of any element x in the compound. Mass % of element x= (atoms of x in formula x molar mass of x (g/mol) / mass (g) of 1 mol of compound) x 100. For a mole of compound you have to use the molar mass and formula to find the mass percent of each element on a mole basis.