CHEM 110 Lecture Notes - Lecture 9: Molar Mass
Document Summary
Chemical formulas (molecular formulas)- indicate the atoms in the molecule and the proportions in which they are found (molar ratio) Need the molecular weight to determine this formula. Formula weight- the sum of the weights of each atom in a formula unit. Changing the coefficient changes the amount of that molecule, not the identity. Changing the subscript changes the identity of the molecule. Empirical formulas- chemical formula with the smallest possible subscripts for a given composition. Found via experimentation: find mass of each element, find # moles of each element, examine mole ratio for formula d. (use molecular weight to find molecular formula) Mass percentage of each element in a compound of element =n aw. Can be determined if the formula is known. Comes from the mass of the element and the compound of element =mass of element mass of sample.
