10Summary 4At equilibrium does a weak acid solution contain mostly products or mostly reactants?At equilibrium does a strong acid solution contain mostly products or mostly reactants?
11Conjugate acids & bases: Standard 5c: continuedConjugate acids & bases:e.x. HF + H2O H3O+ + F-acidDonates hydrogen ionConjugate baseDifferent from acid by a protonBaseAccepts hydrogen ionConjugate acidDifferent from base by a protonCBABCA
12Summary 5 HNO3 + H2O H3O+ + NO3- Label the acid (A), base (B), conjugate acid (ca), and conjugate base (cb) in the following reaction:HNO3 + H2O H3O+ + NO3-
13Conjugate acids & base pairs: e.x. HF + H2O H3O+ + F-Acid and Conjugate base pair = HF & F-A strong acid has a weak conjugate baseA weak acid has a strong conjugate baseBase and conjugate acid pair = H2O & H3O+A strong base has a weak conjugate acidA weak base has a strong conjugate acid
14Summary 6HF + H2O H3O+ + F-Identify the acid and conjugate base. Label each as ‘weak’ or ‘strong’Identify the base and conjugate acid. Label each as ‘weak’ or ‘strong’
15pH measures the concentration (amount) of H3O+ ions in solution Standard 5d: pH scaleDefinition:pH = -log[H3O+]pH measures the concentration (amount) of H3O+ ions in solution
16Summary 7Write the equation for HCl reacting with water to make a hydronium ion and a chloride ionIs the concentration of hydronium ions in this solution high or low?
29Summary 14Complete the following table:[H3O+][OH-]pHpOH10-5M1
305e: acid/base definitions Arrhenius:acids are hydrogen containing compounds that ionize to yield H+ ions in aqueous solution.e.x. HCl(aq) H+(aq) + Cl-(aq)Bases ionize to yield OH- ions in aqueous solutions.e.x. NaOH(aq) Na+(aq) + OH-(aq)Problems: NH3 is not a base according to Arrhenius
31Summary 15Explain why NH3 is not a base according to the Arrhenius definition of a base.
33An acid accepts a pair of electrons (accepts a negative charge) Lewis:An acid accepts a pair of electrons (accepts a negative charge)Acid = proton donor = electron acceptorA base donates a pair of electronsBase = proton acceptor = electron donore.x. HCl + H2O H3O+ + Cl-
36Summary 16Explain the difference between the Bronsted-Lowry definition and the Lewis definition of acids and bases
375g: buffersBuffer = a solution whose pH does not change (much) when acid or base are added.A buffer is a solution made from an acid and its conjugate base
38There are 2 buffer systems in human blood: H2PO4-/HPO42- & H2CO3/HCO3- Example: human blood must have a pH between 7.35 – 7.45 (or we will die)There are 2 buffer systems in human blood: H2PO4-/HPO42- & H2CO3/HCO3-B- + H2PO4- HPO42- + HBB- + H2CO3 HCO3- + HBHB = acid (H+ donor)B- = base (H+ acceptor)