2. They are ELECTROLYTES  When dissolved in water, acids and bases form solutions that conduct electricity (pure water doesn’t). Write definition of electrolyte on your “Acids and Bases” note sheet after “Acids and Bases”

3.  Svante Arrhenius (1884) suggested that:  Acids = substances that release hydrogen ions, H + (aq), in water. Is H+ a cation or an anion??? EX. Hydrogen chloride gas dissolved in water yields the cation H + HCl (g)  H + (aq) + Cl - (aq)

4.  We call this solution hydrochloric acid HCl (aq) because it releases H ions (H + ) in solution Write the definition of an acid on the back of your “Acids and Bases” notes sheet

5.  Arrhenius proposed that bases are substances that release OH - ions when dissolved in water. Is OH - an anion or a cation? EX. Sodium hydroxide dissolves in water and releases the anion OH - NaOH (s)  Na + (aq) + OH - (aq)

6.  We call this base sodium hydroxide NaOH (aq) Write the definiton base on the back of your “Acids and Bases” notes sheet

7.  Look on page 63 in your text  Acids and bases all have safety warnings – they can react strongly and harm your skin, eyes, and lungs  Safety in the lab is of utmost importance

8.  See pg. 63 - 64 in your text and fill in the top half of your “Acids/Bases Nomenclature” notes sheet

9.  pH is a measure of the strength of an acid or base  We use the pH scale to show the power of H + of an acid or base (see p. 65 text)  On your “Acids and Bases” notes sheet, draw the pH scale  Add labels  Indicate strong acids (pH 0 – 3), weak acids (pH 4 – 6), neutral (pH 7), weak base (pH 8 – 10), and strong base (pH 11 – 14)

11.  pH scale allows chemists to express a wide range of hydrogen ions and hydroxide ions because pH numbers are EXPONENTS  An acid of pH 1 has 1 000 000 more H + ions/litre than an acid of pH 6!  A base of pH11 has 1000 more OH - /litre than a base of pH 8

12.  2 ways :  Indicators (remember bromothymol blue and the water plant experiment?), have you ever used litmus paper?  pH meters  Using pg. 64 and 65 in your text, complete the front page of “Acids and Bases” notes sheet.

13. PROPERTIESACIDSBASES pH range Solubility of water Conductivity Taste Reactivity with metals Texture Common state Colour – red litmus Colour – blue litmus Colour – bromothymol blue Colour – phenolphtalein Examples

14.  Test the acids and bases in the depression wells.  Place a few drops of the solutions in the depression wells. DO NOT mix the droppers!!!!  Test the conductivity of each solution using the conductivity meters (enter yes or no in the table)

15.  Test the pH of each solution using the 4 different indicatory papers and a few drops of the bromothymol blue – record the color of the indicator in the acid or alkaline solution in your table.  With the universal (pH) paper – indicate color and pH using the scale provided.  BE SAFE! These are acids and bases!