Changes in Matter (Experiment)

Name:                                                                       Date Performed:

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Report Sheet No. 2

Changes in Matter

I. Objective:

Identify the difference between physical and chemical changes in matter.

II. Materials:

6 test tubes                                                         water

3 evaporating dishes                                           sodium chloride

spatula                                                                hydrochloric acid

tongs                                                                   magnesium ribbon

alcohol lamp                                                       sulfuric acid

10 ml graduated cylinder                                    ammonium chloride

4 250 ml beakers                                                 crushed iced

thermometer                                                        evaporated milk

iron ring and iron stand                                        acetic acid/ vinegar

wire gauze                                                            iron fillings

dropper

Procedure:

A.

1. In a test tube half-filled with water, add about a spatula level of sodium chloride. Shake until all the salt is dissolved. Then transfer the solution into an evaporating dish and heat until it dries up.

2. In another test tube filled with 5 mL hydrochloric acid, place a piece of magnesium ribbon. When the metal has dissolved completely, transfer the liquid into an evaporating dish and heat until it nearly dries up.

B.

1. Fill with water half of each of the three test tubes.

2. Into the first test tube, add 3 mL of concentrated sulfuric acid. Into the second, add a spatula of sodium chloride. And into the third, add a spatula of ammonium chloride.

3. Feel each test tube with your palm. Note any thermal change.

C.

1. Fill with crushed ice about three-fourths of the beaker.

2. Put in the thermometer and note the lowest temperature registered.

3. Observe if the temperature remains constant. Continue observing the changes, if there are any, until 2 or 3 minutes after the last ice crystal has disappeared.

D.

1. Boil half a beaker of water. Record the temperature at which the steam escapes vigorously, and note whether the temperature remains constant.

2. Hold a dry evaporating dish 2 or 3 cm above the beaker. Record your observation.

E.

1. Put 5 mL of hydrochloric acid in a test tube. Add a pinch of iron fillings. Observe what happens.

F.

1. Put 10 mL of vinegar in a test tube. Add liquid milk drop by drop. Observe what happens.

IV. Observations:

A.

B.

C.

D.

E.

F.

V. Questions:

A.

1. Compare the results of heating (a) water with table salt and (b) combining hydrochloric acid with magnesium metal.

2. Describe the type of change undergone by hydrochloric acid and magnesium. Explain your answer.

3. Identify the kind of change that took place when salt disappeared in water. Give reasons for your answer.

B.

1. Compared the results obtained in the three test tubes.

C.

1. Is the melting of ice a physical change? Explain your answer.

2. Did the temperature fluctuate while the ice was melting?

D.

1. Name two processes undergone by matter which were observed in the experiment.

2. Describe what you observed on the evaporating dish.

E.

1. Describe what happens when iron fillings are added to hydrochloric acid.

2. Is a new substance formed when you add iron fillings to hydrochloric acid? How do you know?

F.

1. Describe what happens when milk is added to vinegar.

2. Is a new substance formed? How do you know?

3. When do we say a chemical change has occurred?

VI. Conclusion: