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Universal Indicator Groupmates: Carmen Cheung (4) Chris Chow (7) Sandy Luk (21) Gary Ma (25) Hendrick Wong (28) Brian Wong (29)

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Presentation on theme: "Universal Indicator Groupmates: Carmen Cheung (4) Chris Chow (7) Sandy Luk (21) Gary Ma (25) Hendrick Wong (28) Brian Wong (29)"— Presentation transcript:

1 Universal Indicator Groupmates: Carmen Cheung (4) Chris Chow (7) Sandy Luk (21) Gary Ma (25) Hendrick Wong (28) Brian Wong (29)

2 Acid-base indicator color change with pH Detect acidity alkalinity Detect acidity and alkalinity Plant pigments colour dependent of pH Introduction

3 Explore Extraction of natural indicators Color change Determine Which plant can be an indicator coverpH range Which can cover the pH range Aims

4 Goggles Water bath Water bath Prevent direct heating Precautions

5 Fruits - oranges, apples, grapes Vegetables - beetroot, spinach, cauliflower, ginger, chili hibiscus Flowers – carnation, hibiscus Mortar and pestle Test tube Test tube rack Beaker Dropper Ethanol Stirring rods Deionized or distilled water 0.1M HCl (aq) (pH1) NaOH(s) 100cm3 and 10cm3 Measuring cylinder Apparatus and Chemicals used

6 Preparing pH 1-14 solutions Extracting the indicator Testing the pH solutions with the indicators prepared Testing the solutions with methyl orange and phenolphthalein Comparing the color changes of the indicators Procedures

7 Result Methyl Orange & Phenolphthalein Hibiscus

8 Result

9 Discussion Questions 1.Why hibiscus can as the indicator for different pH ? anthocyanine [1,2] Contains anthocyanine [1,2] Pinkredpurple violet blue Pigment Pink, red, purple, violet and blue Dye extracted Changes its colour Hydrogen ion conc. of the solution

10 Discussion 2.Why other substance used can only detect the pH of alkali ? Equivalence point obtained Coincident the one by standard indicator Flower extract Use of mixed indicator

11 Discussion 3. Any differences between the efficiency of hibiscus and phenolphthalein ? Hibiscus indicator Phenolphthalein Different pH values Different pH values of the testing solutions Cannot showspH values Cannot shows the pH values Different colors Different colors in these solutions Acidic Colorless Alkaline Pink Sharp Sharp color change Easy to detect end-point Gradual Gradual color change Uneasy to find the end-point

12 Discussion Error & Improvement carried out once 1.Experiment was carried out once only again Carried again Raise the accuracy 2.Titration 2.Titration has not been carried out Titration Titration should be carried out With methyl orange, phenolphthalein and hibiscus indicator respectively Color change can be observed

13 Discussion parts of flowers & fruits 3.Only parts of flowers & fruits crushed to make indicators crushed more times Should be crushed more times used twiceone titration Should be used twice by one titration

14 Discussion 4.Conc. of flowers & fruits not investigated 4.Conc. of flowers & fruits in indicators for color change not investigated Different conc. of the flowers and fruits in indicators Different effects Different effects on color change Indicator of different conc. should be prepared in each titration

15 Discussion foam state 5.Solution extracted in foam state Not pure Not pure enough Affected color change

16 Discussion Limitation Inaccurate equipment Inaccurate equipment for extracting pure solution

17 Hibiscus Hibiscus Universal indicator Distinct color changes Conclusion

18 Poor time management Poor preparation A gain of knowledge Deeper interest in Chemistry Reflection

19 The End Universal Indicator


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