Acids and Bases

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PURPOSE

To investigate the reactions of a typical acid (dilute hydrochloric acid) with metals, metal oxides, carbonates and bases.

APPARATUS

The following materials in order to complete this experiment:

Dropper bottles containing 0.1M solutions of hydrochloric acid or limewater (calcium hydroxide) and sodium hydroxide.

Dropper bottle of bromothymol blue indicator

Small samples of the following metals: zinc, copper turnings, magnesium and iron

Copper (II) oxide powder

Magnesium oxide

Marble chips (calcium carbonate)

Sodium carbonate

12 test tubes and test tube holder

Bunsen burner

Stopper or cork

Wax taper and matches

PROCEDURE

(a) REACTION WITH METALS

Place a small piece of magnesium ribbon in a test tube and add about 2mL of dilute HCL.

Stopper the test tube and allow the gas to accumulate.

Remove stopper and test for the gas that evolved by holding a lighted taper to the mouth of the test tube.

Repeat using zinc sample.

Repeat using copper sample.

Repeat using iron sample.

(b) REACTION WITH METAL OXIDES

Place a very small amount (the size of a few grains of rice) or copper (II) oxide in a test tube and add about 2mL of hydrochloric acid. Warm the test tube gently. If no change is observed, allow to stand for a while before making further observations.

Repeat this procedure using magnesium oxide and hydrochloric acid.

(c) REACTION WITH CARBONATES

Add several marble chips to a test tube.

Add about 2mL of limewater to a second tes...

... middle of paper ...

...ions are formed. Carbonates always produce CO2 and H2O. Also, in the presence of carbon dioxide, limewater becomes cloudy. Errors and improvements for this experiment would be the following: using and adding too much indicator that results in a greater pH reading. In order to be as accurate as possible, one must be as accurate as can be. Inaccuracy in this measure will enable and reveal inaccurate results. Another error was the presence of other acids in the test tube that was rinsed with water. This was evident when the acid was placed in the test tube before 2 drops of the indicator was dropped. This can also lead to inaccurate results.

CONCLUSION

This experiment achieved the aim. It was concluded that acids and metal oxides form salt and hydrogen gas. Acids and carbonates form salts, water and carbon dioxide. Lastly, acids and bases result in salt and water.

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