Exam 2 Flashcards
Stoichiometry: Moles to Moles
Mole A → Stoichiometric relationship between mole A and Mole B → Mole B
Stoichiometry: Mass A to Mass B
Mass A → Mole A → Stoichiometric relation of mole A & B → Mole B → Mass B
Molecular Formula(Normal)
Lists the exact number and types of atoms of which molecule is composed.
Empirical Formula
Lists the relative type and number of atoms in the compound. Lowest ratio possible of elements. E.G.: P4O10 →P2O5
Empirical Formula by Percent Composition
1) Convert percent to mass by assuming 100 grams of sample if only given percent.
2) Convert mass to moles.
3)Divide by smallest number of moles present.
Molecular Formula by Percent Composition
Given amu, MM of compound(g/mol)/ MM of Empirical Formula (g/unit)
Avagadro’s Number
6.022 × 10²³
Endothermic Reaction
ΔH = +kJ
Exothermic Reaction
ΔH = -kJ
Enthalpy Change in kJ
Mass of element → Mole of Element → kJ of Element
Identifying reduction & oxidization
Use oxidation state rules:
1) Single atoms in element state = 0
2) Atoms in monatomic ion = Charge of individual element
3) Compound: F -1, O-2
4) Compound: All other element balance other oxidation.
Reduction - Lower oxidation number
Oxidization - Added oxidation number
Identifying Spectator Ions
Ions from complete ionic equations that appear on both side.
Net Ionic Equation
A chemical equation in which only those ions undergoing chemical changes during the course of the reaction are represented. No reaction when reactant/product are all aqueous and ionic.
Remove spectator ions.
Precipitate = Insoluble Solid
Percent Yield
Actual Yield/Theoretical Yield * 100%
Finding Limiting Reagent
Gram of A x (Mol A/Gram A) x (Mol A/Mol B) = Max mol product
Lowest mole product is limiting reagent.
Finding Theoretical Yield(Round Final for SF)
Lowest Mol Product A x MM A/1 mol A
