CHM1046 - Exam 3 Questions And Answers Fully Solved Graded A+

reversible reactions - correct answers a chemical reaction in which the products can react to re-form the reactants chemical equilibrium - correct answers when the rate of the forward reaction equals the rate of the reverse reaction + the concentration of the products + reactants remain unchanged reactant concentrations start high & _________ as the reaction proceeds. the forward rate, which depends on collision of the reaction, decreases. - correct answers decreases product concentrations start at zero & ________ as the reaction proceeds. the reverse rate, which depends on collisions of the products, increases. - correct answers increases eventually, the forward rate is equal to the reverse rate & the concentrations are CONSTANT. this is ______________ - correct answers equilibrium le chateliers principle - correct answers when a system at equilibrium is placed under stress, the system will undergo a change in such a way as to relieve that stress factors that affect equilibrium - correct answers - concentration - temperature - pressure [for gaseous systems only!] - presence of a catalyst add more reactant ---- - correct answers shift to products remove reactants ---- - correct answers shift to reactants add more product ---- - correct answers shift to reactants remove products ---- - correct answers shift to products if the volume of a gas mixture is compressed, the overall gas pressure will ______________. - correct answers increase reaction shift right when pressure __________ - correct answers increases reaction shift left when pressure ___________ - correct answers decreases inert substance - correct answers a substance that is not reactive with any species in the equilibrium system - do not affect the equilibrium system - if the substance does react with a species at equilibrium, then there will be a shift a catalyst has ___ effect on a system at equilibrium! - correct answers no exothermic reactions favor _____ temperature conditions - correct answers low endothermic reactions favor ______ temperature conditions - correct answers high endothermic reactions add heat --- - correct answers shift to products endothermic reactions remove heat ---- - correct answers shift to reactants exothermic reactions add heat ---- - correct answers shift to reactants exothermic reactions remove heat ---- - correct answers shift to products what are acids? - correct answers substances that donate hydrogen ions (protons), H+, to form hydronium ions, H3O+, when dissolved in water characteristics of acids - correct answers 1. acids turn blue litmus paper red 2. acids taste sour 3. can burn skin common acids - correct answers - Sulfuric acid H2SO4 - Nitric acid HNO3 - Phosphoric acid H3PO4 - Hydrochloric acid HCl - Acetic acid CH3COOH - Carbonic acid H2CO3 strong acids: - correct answers ionize (break into cations + anions) almost completely & conduct electricity well strong acids - correct answers - nitric acid [HNO3] - hydrochloric acid [HCl] - hydrobromic acid [HBr] - hydroiodic acid [HI] - sulfuric acid [H2SO4] - perchloric acid [HClO4] weak acids: - correct answers do not completely ionize weak acids - correct answers - acetic acid (vinegar) - citric acid - all others what are bases? - correct answers substances that form hydroxide ions (OH-) when in water or accept H+ ions common bases - correct answers - aluminum hydroxide Al(OH)3 - calcium hydroxide Ca(OH)2 - magnesium hydroxide Mg(OH)2 - sodium hydroxide NaOH - ammonia NH3 characteristics of bases - correct answers 1. taste bitter 2. slippery 3. bases turn red litmus paper blue 4. can burn skin a substance is neutral when: - correct answers 1. it does NOT ionize at all, therefore no H+ or OH- ions 2. it has equal concentrations (amounts) of H+ & OH- ions concentration is _____ the same as strength - correct answers not concentration deals with the amount of hydronium ions in the solution, compared to the amount of _______ in the solution - correct answers water more acid or base + less water = - correct answers more concentrated more ions + less molecules = - correct answers stronger pH scale --- - correct answers 0-14 pH 0-6 = - correct answers ACID [closer to 0 is more acidic] pH 8-14 = - correct answers BASE [closer to 14 is MORE basic] pH 7 = - correct answers neutral [H3O+ concentration = OH- concentration] pH = - correct answers - log [H+] stronger the acid = - correct answers weaker is its conjugate base (& vice versa) NaCl = - correct answers salt + strong electrolyte C2H5OH = - correct answers covalent + not electrolyte H2SO4 = - correct answers acid + strong electrolyte NaOH = - correct answers base + electrolyte C12H22O11 = - correct answers covalent + not electrolyte CaI2 = - correct answers salt + electrolyte HF = - correct answers acid + weak electrolyte