Presentation on theme: "Chemistry Chapter 20-21 Acids and Bases Electrolytes: Solutions that conduct electrical current easily. Aqueous solutions of acids and bases are electrolytes."— Presentation transcript:
Electrolytes: Solutions that conduct electrical current easily. Aqueous solutions of acids and bases are electrolytes. Ionic solids that dissolve in water are electrolytes.
The ammeter measures the flow of electrons (current) through the circuit. If the ammeter measures a current, and the bulb glows, then the solution conducts. (Electrolyte) If the ammeter fails to measure a current, and the bulb does not glow, the solution is non-conducting. (Non-electrolyte) Electrolytes: The ability of a solution to conduct an electric current.
NaCl (s) Na + (aq) + Cl - (aq) Dissociation: Water surrounds ions and dissolves them. Dissociation equation:
Dissociation of HCl HCl H + + Cl - Dissociation equation. General Dissociation equation. HA H + + A - A - represents the anion Cl H H H
Basic definition: Acids:Produce hydrogen ions, H +, when dissolved in water. Bases:Produce hydroxide ions, OH -, when dissolved in water.
Some Properties of Acids Acids taste sour Acids react with certain metals to produce hydrogen gas. 2 HCl (aq) +Mg (s) H 2(g) +MgCl 2(aq) Acids effect indicators Blue litmus turns red Phenolphthalein turns colorless Methyl orange turns red
Acids Effect on Indicators Blue litmus paper turns red in contact with an acid.
Bases Effect on Indicators Red litmus paper turns blue in contact with a base. Phenolphthalein turns purple in a base.
Naming Acids Acids without oxygen: Hydro_______ic acid HF = HCl = HBr = HCN = Hydrofluoric acid Hydrochloric acid Hydrobromic acid Hydrocyanic acid CN - = cyanide anion H 2 S = Hydrosulfuric acid HI = Hydroiodic acid
Naming Acids H + + (anions with oxygen) Acids with oxygen: “ ate-ic ite-ous” Anion nameAcid name ____ate____ic acid ___ite___ous acid HNO 3 = Anion NO 3 -1 = nitrate HNO 2 = Nitr__?__ acid Nitrous acid Nitr__?__ acid Nitric acid Anion NO 2 -1 = nitrite
Naming Acids H + + (anions with oxygen) Formula H + with AnionAcid name H 2 SO 4 Sulfuric acid 2H + + SO 3 2- = sulfite HC 2 H 3 O 2 2H + + SO 4 2- = sulfate H 2 SO 3 Sulfurous acid H + + C 2 H 3 O 2 -1 = AcetateAcetic acid H 3 PO 4 3H + + PO 4 3- = PhosphatePhosphoric acid H 2 CO 3 2H + + CO 3 2- = CarbonateCarbonic acid
Naming Acids H + + (series of Cl and O) Formula H + with AnionAcid name HClHydrochloric acid H + + ClO -1 = hypochlorite HClO 2 H + + Cl - = Chloride HClOHypochlorous acid H + + ClO 2 -1 = ChloriteChlorous acid HClO 4 H + + ClO 4 -1 = perchloratePerchloric acid HClO 3 H + + ClO 3 -1 = ChlorateChloric acid Hypo = less oxygen Per = more oxygen
Naming Bases Same method as naming ionic compounds Formula Cation with OH - Base name NaOHSodium hydroxide (Lye) Na + + OH - KOHPotassium hydroxide K + + OH - Ca(OH) 2 Calcium hydroxide (Lime) Ca 2+ + 2 OH - Mg(OH) 2 Magnesium hydroxide (Milk of magnesia) Mg 2+ + 2 OH - Al(OH) 3 Aluminum hydroxide Al 3+ + 3 OH - NH 3 Ammonia (common name) (No ions) Molecules that contain nitrogen are weak bases.