Aim # 28: What is the difference between an acid and a base? H.W. # 28 Review p. 503 Study pp. 226-29 Ans. ques. p. 532 #1 p. 246 # 17,18,21-23

I Properties of acids Acids are molecular substances whose water solutions produce H+ ions as the only positive ions in solution. The properties of acids are due to this excess of H+ ions. Acids conduct electricity- they are electrolytes. will react with metals above H in Ref. Table J to produce H2 gas. Acids cause color changes to acid-base indicators. Ref. Table M common acid-base indicators Dilute aqueous solutions of acids have a sour taste. e.g. lemons, limes, and vinegar all contain acid.

Complete the following equation for the ionization of NaOH(s) in water. NaOH(s) +H2O → II Base (Arrhenious’ definition)- a substance whose water solution yields hydroxide ions (OH-) as the only negative ion in solution. e.g. NaOH(s) + H2O(l) → Na+(aq) + OH-(aq) NH3(g) + H2O(l) → NH4+(aq) + OH-(aq) Ref. Table L common bases

III Properties of bases Aqueous solutions of bases conduct electricity- they are electrolytes. Bases cause color changes to acid-base indicators. Ref. Table M Bases react with acids to form a salt and water. (neutralization) e.g. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l) Aqueous solutions of bases feel slippery.

IV Salts- a salt is an ionic compound containing a positive ion other than H+ and a negative ion other than OH-. e.g. HCl(aq) hydrochloric acid KCl potassium chloride Ca(OH)2 calcium hydroxide CaBr2 calcium bromide Remember, Acid + Base → Salt + Water (neutralization reaction) e.g. 2HCl(aq) + Ca(OH)2(aq) → CaCl2(aq) + H2O(l)