SNC1D1 LAB: Chemical or Physical Change
Physical changes do not alter the composition of matter, but chemical changes do.
Without careful testing, you cannot always know for certain that a chemical change has occurred and a new substance has formed. You can, however, observe and experiment and look for evidence to make an inference about the kind of change. This is what you will do here. i) Wear your safety glasses at all times. ii) Always report spills of any chemicals to your teacher. iii) Handle chemicals with care as they may be toxic, irritant or corrosive. iv) Hydrochloric acid is a caustic liquid. If any gets on your skin or clothes,
rinse it off immediately with plenty of running water or tell your teacher. v) Copper (II) sulfate is a poison and an irritant. If any gets on your skin, rinse it off immediately with plenty of running water or tell your teacher. vi) Wash your hands thoroughly at the end of this investigation
Master Yoda
Part 1 – Procedure
1.
Make a table like the one below. Give your table a title.
Part of
Investigation
Starting
Substance
Physical
Properties
Changes After
Mixing (state, temp, colour, etc.)
Physical or
Chemical
Change
2.
Pour 2 to 3 mL of lead (II) nitrate solution into a clean test tube.
3.
Pour 2 to 3 mL of potassium iodide into a second test tube.
4.
Observe and record the physical properties of each starting substance before mixing the substances together.
5.
Carefully pour the contents of one test tube into the other.
6.
Record what happens after the substances are mixed (i.e. what do you see immediately, what do you see after a few minutes)
7.
Record whether you think a physical or chemical change has taken place.
Much Learning You Have Yes!

Master Yoda
Part 2
1.
Pour about 4 to 5 mL of dilute hydrochloric acid into a clean, dry test tube. Record your observations.
Hint: if a quantity is described as
“about”
you do not have to measure it. You can use an approximate amount. To approximate the volume of a substance, look at the test tube you will be using. If the opening is about 1 cm in diameter, then a depth of 1 cm corresponds to a volume of about 1 mL.
2.
Using a scoopula, obtain a pea-sized sample of calcium carbonate. Record your observations.
3.
Carefully add the calcium carbonate to the hydrochloric acid. Record your observations.
Record your observations.
Part 3
1.
Using a scoopula, obtain a few crystals of copper (II) sulfate. Record your observations.
2.
Pour about 5 mL of distilled water into a clean, dry test tube. Record your observations.
3.
Add the copper (II) sulfate to the water, place a stopper in a test tube, and gently shake the test tube. Record your observations.
4.
Save the test tube and the liquid in it for Parts 4 and 5 of this investigation.
Part 4
1.
Use an eyedropper to place two drops of the liquid from Part 3 in the evaporating dish. Record your observations.
2.
Place the evaporation dish on the hot plate. Gently heat on hot plate set between 4 –
3.
5. Record your observations
CAUTION: Keep your face away from liquid. It may spit as it dries.
Much Learning You Have Yes!

4.
Carefully remove evaporation dish from hot plate and allow it to cool on table. Wash evaporation dish as instructed by your teacher.
Part 5
1.
Examine the test tube and liquid from Part 3. Record your observations. Place the test tube in the rack.
2.
Examine the steel wool, and record your observations.
3.
Add the steel wool to the liquid in the test tube. Record your observations.
Part 6
1.
Pour 2 to 3 mL of hydrogen peroxide solution into a clean dry test tube. Record your observations.
2.
Use a scoopula to obtain a small sample of manganese dioxide. Record your observations.
3.
Carefully add the manganese dioxide to the hydrogen peroxide. Record your observations.
Part 7
1.
Pour 4 to 5 mL of dilute hydrochloric acid into a clean dry test tube. Record your observations. Clean the magnesium ribbon with a small piece of steel wool.
2.
Carefully add the magnesium ribbon to the hydrochloric acid. Record your observations of the magnesium ribbon and what happens.
Master Yoda
Part 8
1.
Pour 4 to 5 mL of distilled water into each of three clean test tubes. The level of the water should be the same in all the test tubes. You will add substances to two of the test tubes. The third will act as a control.
2.
Using a scoopula, obtain a pea size sample of calcium oxide. Record your observations.
3.
Add the calcium oxide to one of the test tubes. Put a stopper in the test tube, and gently shake the test tube. Record your observations.
Much Learning You Have Yes!

4.
Using a scoopula, obtain a pea size sample of ammonium nitrate. Record your observations.
5.
Add the ammonium nitrate to one of the test tubes. Put a stopper in the test tube, and gently shake the test tube. Record your observations.
6.
Compare the three test tubes, and record any differences.
7.
Dispose of all materials as instructed by your teacher.
8.
Wash and dry test tubes, evaporation dishes and stoppers and return to appropriate storage area or as instructed by teacher.
Discussion Questions
1.
What physical changes took place? What evidence supports your inferences?
2.
What chemical changes took place. What evidence supports your inferences?
3.
Describe what happens when potassium iodide is added to lead (II) nitrate. (A solid that is formed during a chemical change and settles out of the solution is called a precipitate .)
4.
What did you see when you added manganese dioxide to hydrogen peroxide? What might be happening? Explain your reasoning.
Master Yoda Much Learning You Have Yes!