SCIENCE 08 CHEMISTRYNotebook Page E

EXPERIMENT # 1

OBSERVING A CHEMICAL REACTION

PROBLEM:

1.To distinguish chemicals by their properties.

2.To recognize evidence for the occurence of a chemical reaction.

HYPOTHESIS:

It will be possible to distinguish the chemicals by their and/or their

while the evidence that a chemical reaction is occurring will be that

APPARATUS AND MATERIALS:

100 mL beaker with 20 mL of liquid "A" (0.1 M copper II sulphate solution)

100 mL beaker with 20 mL of liquid "B" (1.0 M ammonia solution)

100 mL beaker with 20 mL of liquid "C" (1.0 M hydrochloric acid solution)

2 test tubes250 mL beakermasking tapestopper

medicine droppertest tube racknailsafety goggles

PROCEDURE:

1. Observe the colours of liquids "A", "B" and "C". Record your observations in Table I provided.

CAUTION:DO NOT LET ANY OF THE LIQUID TOUCH YOUR SKIN OR YOUR CLOTHES. IF YOU SPILL ANY, WASH THE AREA WITH WATER AND DRY IT WITH A PAPER TOWEL. THEN TELL YOUR TEACHER. SAFETY GOGGLES MUST BE WORN !

2. Carefully observe the odours of Liquids "A", "B" and "C". Then try your best to describe them. Smells can be described as fragrant, fruity, suffocating (like Ammonia), pungent, sweet, sharp or sour. Some materials are odourless. Record your observations on Table I.

3.Hold the beakers of Liquids "A", "B" and "C" up to the light one at a time. Observe whether they are clear or cloudy. Remember that a liquid may be coloured and still be translucent. Record your observations in Table I.

4. Pour liquid "A" into a clean test tube until it is about 2 cm deep. Fill a medicine dropper with liquid "B". Add a little of liquid "B" (about 10 drops) to liquid "A" in the test tube. Gently shake the test tube to mix the liquids. Observe the mixture. Keep the liquid for Procedure #5 ! Record your observations in Table I.

5.Continue to add drops of liquid "B" and shake the test tube until the mixture becomes clear.

Keep the liquid for Procedure #7. Record your observations in Table I.

6.Half fill a 250 mL beaker with water in which to clean your medicine dropper.

7.Fill the medicine dropper with Liquid "C". Add liquid "C" to the test tube from Procedure #5 one drop at a time. Gently shake the test tube after each drop to mix the liquids. Stop adding "C" when the mixture is cloudy. Record your observations in Table I. Keep the liquid for Procedure #8.

8.Add more drops of "C" and shake the mixture until it becomes clear. Record your observations in Table I. Keep the liquid for Procedure #9.

EXPERIMENT #1: CHEM REACTIONS PAGE 2Notebook Page E

9.Put your initials on a small piece of masking tape and put it on the test tube or record the "number" on the test tube. Put a nail into the test tube and place the test tube into the test tube rack or other convenient support. Leave it there until your next science class and then observe it.

10.Wash the test tube, beakers, and,medicine dropper with water. Left over chemicals may be washed down the drain with plenty of running water. Wash your hands !

OBSERVATIONS:

1.Record your observations for Procedures #1 - 8 in Table I.

2.For Procedure #9 describe the changes that occur in both the solution and the nail.

3.Record the appearance of the nail after it has been sitting overnight.

DISCUSSION:

1.What allows us to distinguish among different materials ?

2.How is it possible to tell when new materials are formed in a chemical reaction ?

3.At the end of procedure #5, what new property indicated that a new material was formed ?

4.At the end of Procedure #7, what property of the solution indicated that it was different from liquid "A"?

5.Is it possible to return a mixture to its original properties ? Which property was observed toreturn to its original condition?

CONCLUSION:

Make a judgement statement about your original hypothesis and answer the two questions in the purpose.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXPERIMENT #1: CHEM REACTIONS PAGE 3Notebook Page E

TABLE I: CHANGES IN PROPERTIES

SAMPLECOLOURSMELLCLEAR or CLOUDY

LIQUID "A"

LIQUID "B"

LIQUID "C"

LIQUID "A" +

A LITTLE "B"

LIQUID "A" +

A LOT of "B"

LIQUID "A" + "B"

+ A LITTLE "C"

LIQUID "A" + "B"

+ A LOT of "C"

Safety Information:

1.Liquid "A" is poisonous but harmless to the skin.

2.Liquids "B" and "C" are poisonous and harmful to the skin and clothes.

3.All of these liquids are harmful to the eyes.

4.Liquid "C" being corrosive is the most dangerous.

5.The chemical names for each of the liquids are

Liquid "A"-0.1 M Copper II Sulphate

Liquid "B"-1.0 M Aqueous Ammonia

Liquid "C"-1.0 M Hydrochloric Acid