Acids and Bases And Neutralisation Reactions p

What are acids? Working together with your bench group & using the information in your text book (Ch 4 p 80), expand this Mind Map Acids Have a sour taste eg Are used for

What are bases?  Working together with your bench group, expand this Mind Map bases Have a bitter taste (think of baking soda!) eg Are used for

Experiment 13: Testing for Acids and Bases Aims:  to determine which substances are acids and bases using universal indicator  to compare the colour produced using plant indicators with those produced using universal indicator

Materials  Glass plate with wells  Droppers  Universal indicator  Colour chart  Red Cabbage Indicator  Hydrochloric acid (HCl)  Sodium Hydroxide (NaOH)  Vinegar  Lemon Juice  Sodium bicarbonate (NaHCO3)  Water (from tap)  Other Substances as supplied

Method 1.Collect the substances listed above and place about 0.5 ml in separate wells on the glass plate, as shown. 2.Use a new well for each substance. 3.Add two drops of Universal indicator to each well 4.Record the colour that the indicator became 5.Use the glass test plate outline supplied to estimate the pH and record this also. 6.Test these substances with Red Cabbage Indicator and record the colours on a new sheet  Hydrochloric acid (HCl)  Sodium Hydroxide (NaOH)  Vinegar  Lemon Juice  Sodium bicarbonate (NaHCO3)  Water (from tap)  Copy the table on the next slide into your workbook  Safety Issues?

Comparing Indicators Substance testedColour with Universal Indicator pH as read from Chart Colour with Red Cabbage Indicator Hydrochloric acid Sodium hydroxide Vinegar Lemon juice Sodium bicarbonate solution Tap water

Neutralisation Reactions  Acids and bases react together! (Remember the vinegar and Bicarb?)  The general overall word equation is Acid + Base  a Salt + water Except if you use a bicarbonate or carbonate (which are bases) and then it’s Acid + bicarbonate/carbonate  a Salt + water + carbon dioxide

Try This! 1.Put a small amount of vinegar + 2 drops only of indicator in a test tube 2.Add 0.1 M NaOH drop by drop 3.Can you get the pH to be just 7?

Activities  On the Intranet in the Acids and Bases Section try  GEMS Alien Juice Bar  Treasure Puzzle