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Acids and Bases

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EXPERIMENT # 1

Purpose:

How can cabbage juice indicate if a substance is an Acid and Base?

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Apparatus Vinegar, Baking Soda, Cornstarch, Salt,Lemon Juice, Orange Juice, Cream of Tartar, Ammonia, Hot Plate, Pot, Water, Purple Cabbage, Test Tube Rack, Test Tubes, Beaker, Graduated Cylinder, Stirring Rod, Lye, medicine dropper.

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Method:• Fill each test tube with 15 ml of purple

cabbage juice.• Add 5 drops of each test solution to the

test tube.• Observe any color changes of the

cabbage juice in your data table, record the color and relative PH of each solution.

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• Data Table:• Test Solution Cabbage Juice Color Relative PH• Vinegar• Lye• Baking Soda• Lemon Juice• Ammonia• Cream of tartar• Salt• Orange Juice• Cornstarch

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Diagram

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Conclusion:Purple cabbage Juice is an indicator that turns pink when it is mixed with an acid. It turns yellow/green/blue when it is mixed with a base. It stays the same color purple when it is mixed with a neutral substance.

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Acids

Taste sour

Corrode metals

React with bases to form salts and

water

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Bases

Taste bitter, chalky

Feel soapy, slippery

React with acids to form salts and

water

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Describe the solution in each of the following as: 1) acid 2) base or 3)neutral.

A. ___soda

B. ___soap

C. ___coffee

D. ___ wine

E. ___ water

F. ___ grapefruit

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Describe each solution as:

1) acid 2) base or 3) neutral.

A. _1_ soda

B. _2_ soap

C. _1_ coffee

D. _1_ wine

E. _3_ water

F. _1_ grapefruit

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Some Common Acids

HCl hydrochloric acid

HNO3 nitric acid

H3PO4 phosphoric acid

H2SO4 sulfuric acid

CH3COOH acetic acid

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pH of Some Common Acids

gastric juice 1.0

lemon juice 2.3

vinegar 2.8

orange juice 3.5

coffee 5.0

milk 6.6

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pH of Some Common Bases

blood 7.4

tears 7.4

seawater 8.4

milk of magnesia 10.6

household ammonia11.0

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The pH Scale

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7 8 9 10 11 12 133 4 5 62 141

The pH Scale

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The pH Scale

Neutral Weak Base

Strong

Base

Weak Acid

Strong Acid

7 8 9 10 11 12 133 4 5 62 141 7 8 9 10 11 12 133 4 5 62 141 9 10 11 123 4 5 621

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7 8 9 10 11 12 133 4 5 62 141 9 10 11 123 4 5 621

Neutral Weak Base

Strong

Base

Weak Acid

Strong Acid

The pH Scale