Stoichiometry

Stoichiometry Relative Atomic/Formula Mass relative atomic mass ⇒ Aᵣ how much 1 mole of an element weighs (in grams) on periodic table relative formula mass ⇒ Mᵣ how much 1 mole of a compound weighs (in grams) all Aᵣ in a compound added together Moles if given # of moles mass = mass of 1 mole x # of moles if given a mass # of moles = mass / mass of 1 mole Percentage Composition expresses which elements are in a compound, and how much there is of each (as a percentage of the whole compound) mass of substance (as a percentage) = mass of element / mass of compound x 100 Empirical Formula shows the ratio of each element in a compound steps to find empirical formula: find grams of each substance divide by their Aᵣ divide by largest result multiply/divide if necessary use this ratio to write empirical formula Molecular Formula shows the exact number of atoms from each element in a compound steps to find molecular formula: actual formula mass / empirical formula mass multiply empirical formula by this number use these numbers to write molecular formula Concentration concentration of a solution ⇒ amount of salute (in grams or moles) that is dissolved in 1 dm³ or 1L of a solution to find concentration: concentration (mol/dm³) = amount of solute (moles) / volume of solution (dm³)