General Chemistry I - Review Sheet | CHEM 131, Study notes of Chemistry

Download General Chemistry I - Review Sheet | CHEM 131 and more Study notes Chemistry in PDF only on Docsity! Chapter 4 Test Review Chapter 4  Writing molecular, total ionic, and net ionic equations. o Molecular equations only show all the reactants and products as if they were intact, undissociated compounds. o Total ionic equations show all the soluble ionic substances dissociated into ions. o Net ionic equations eliminate spectator ions (species not involved in the chemical change) and show the actual chemical change taking place. o Example: Molecular equation: Ba(NO3)2 (aq) + Na2CO3 (aq) à BaCO3 (s) + 2NaNO3 (aq) What is the total ionic and net ionic equation for this reaction? Total ionic: Ba2+(aq) + 2NO3-(aq) + 2Na-(aq) + CO32-(aq) à BaCO3(s) + 2Na+(aq) + 2NO3- Net ionic: Ba2+(aq) + 2NO3-(aq) + 2Na-(aq) + CO32-(aq) à BaCO3(s) + 2Na+(aq) + 2NO3- Ba2+(aq) + CO32-(aq) à BaCO3(s) o Writing ionic equations for acid-base reactions.  An acid produces H+ ions when dissolved in water; a base produces OH- ions when dissolved in water.  The essential change in all aqueous reactions between a strong acid and a strong base is that an H + ion from the acid and an OH - ion from the base form a water molecule.  The compound that results from the reaction is a salt.  Example: HX (aq) + MOH (aq) à MX (aq) + H2O (l) acid base salt  Predicting whether a precipitate will form. o Note the ions present in the reactants. Ca2+ + 2Cl- + 3Cs+ + PO4-3 à o Consider the possible cation-anion combinations. Ca2+(aq) + 2Cl- (aq)+ 3Cs+ (aq)+ PO4-3(aq) à Ca3(PO4)2 (?) + CsCl (?) o Decide whether any of the combinations is insoluble (using the solubility rules). Ca2+(aq) + 2Cl- (aq)+ 3Cs+ (aq)+ PO4-3(aq) à Ca3(PO4)2 (s)* + Cs+(aq) + Cl-(aq) Note that BaCO3 is not dissociated b/c it’s a solid. This is a generic reaction. Cation: positively charged ion. Anion: negatively charged ion.