Acids and Bases. G.10 Science Chemistry Shaftesbury High School

Transcription

1 G.10 Science Chemistry Acids and Bases 2240 Grant Avenue Winnipeg, Manitoba R3P 0P7 Phone: Fax:

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3 G.10 Science Acids and Bases What is acid-base exactly? Acids were defined by Swedish chemist Arrhenius Bases are also defined as The symbol (g) is used

4 G.10 Science Acids and Bases How can we know it s an acid or base? One easy way is to use indicators. One familiar example

5 G.10 Science Acids and Bases What would happen if an acid and a base were mixed up? Let s think about it this way. What would happen if If the spectator ions Showing that an acid reacts with a base

6 G.10 Science Acids and Bases Acid and Base Properties Acid Properties Base Properties

7 G.10 Science Cracking the Chemistry Code BLM 7-5 McGraw-Hill Ryerson Ltd

8 G.10 Science Identifying Acids and Bases BLM 7-6 McGraw-Hill Ryerson Ltd

9 G.10 Science Identifying Acids and Bases BLM 7-8 McGraw-Hill Ryerson Ltd

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11 G.10 Science Lab: Acids and Bases 1. Obtain 12 plastic pipets, a plastic spot plate, 11 pieces of blue litmus paper, 11 pieces of red litmus paper, 11 cm of ph paper, a piece of paper towel, and a centimeter ruler. 2. Half fill 12 spot wells with each of the 11 household products and the phenolphthalein indicator. 3. Your well plate should be arranged according to the following chart. Row E Row F Solution 7 Solution 8 Solution 9 Solution 10 Solution 11 Phenolpthalein Solution 1 Solution 2 Solution 3 Solution 4 Solution 5 Solution 6 5. Take your spot plate back to your seat. 6. Test all solutions with red litmus paper. Place your used papers on the paper towel to be discarded. Record your results in the data table provided. 7. Test all solutions with blue litmus paper. Place your used papers on the paper towel to be discarded. Record your results in the data table provided. 8. Test all solutions with ph paper. Match the color of the paper to the corresponding ph value. Place your used papers on the paper towel to be discarded. Record your results in the data table provided. 9. Place a drop of phenolphthalein indicator into each solution in rows E & F. Swirl the spot plate to mix the solutions. Record your results in the data table provided. Clean Up 11. Once all solutions have been tested, throw away all used litmus and ph papers, rinse all solutions down the sink with lots of water, and rinse the spot plate. 12. Clean out all dropper pipets with water, and return all equipment to its original location. Substance Red Turns Blue? Blue Turns Red? ph Phenolphthalein Colour Acid or Base?

12 G.10 Science Lab: Acids and Bases Summary Report: Choose and complete one of the following methods with your partner for displaying the properties of acids and bases and showing which solutions are acid, neutral, or base. You may need to read the text book to find the properties of acids, bases, and neutrals. A. Make a Venn diagram and fill in the names or draw pictures of the items that were in each of the solutions in the correct section in the diagram and write the properties in the correct section. (See example below.) B. Write a brief report about acids, bases, and neutrals in paragraph form and include examples from the testing lab. C. Draw a concept map or word web comparing and contrasting acids and bases and add descriptive words and examples. (See example at the bottom.) D. Create a narrative poem, song, or story about the acid, base and neutral solutions and describe their properties. E. Make a poster showing pictures of the items that were acids, bases, and illustrating the properties of each. F. Create a continuum (similar to a time line) with the solution substances listed along it in order of their ph. Show the ph and label the continuum to show where acids, bases, and neutral occur along with descriptive phrases. Sample Venn Diagram Sample Concept Map

13 G.10 Science Lab 2: Acids and Bases Identification Objective: Determine whether the solutions assigned to your group are acids or bases. Additionally, determine as accurately as possible the ph range of each of the solutions. Materials: 3 samples of solution. Please record their # here: 3 blue litmus paper 3 red litmus paper 3 ph paper 1 set of indicators (phenolphthalein, methyl orange, bromothymol blue, alizarin yellow, indigo carmine) 1 sampling tray 5 droppers Small beaker (use to rinse droppers to avoid contamination) Background Name of Inidicator Acid Colour ph range for colour change Base Colour Methyl Orange red yellow Bromothymol Blue yellow blue Litmus red blue Phenolpthalein colourless red Alizarin Yellow yellow red Indigo Carmine blue yellow Explanation If a solution turned the alizarin yellow indicator red (ph=12) and the indigo carmine indicator blue (ph=11.4), then the ph of this solution must be between 11.4 and 12.0.

14 G.10 Science Lab 2: Acids and Bases Identification Observation Data Table Name of Inidicator Solution Solution Solution Methyl Orange Bromothymol Blue Red Litmus Blue Litmus ph Paper Phenolpthalein Alizarin Yellow Indigo Carmine Conclusion Solution is an/a and has a ph of. Solution is an/a and has a ph of. Solution is an/a and has a ph of.