Chem 10
Brakke
Physical and Chemical Changes
Lab Activity
ECA – Topic 01
Name………………………………………………………..
Introduction:
Chemistry is the study of matter and the changes it undergoes. These changes can be broken down into two classes:
physical and chemical changes. In a physical change, one or more physical properties of a substance are altered. Grinding, melting,
dissolving and evaporating are all physical changes. No new substance or substances are formed as a result of a physical change.
A chemical change results in the formation of one or more new substances. These new substances differ in chemical
properties and composition from the original substance. Rusting and burning are two examples of chemical change.
Procedure:
For each part below, complete the procedure taking observations before and after and record them in your lab notebook.
Determine whether a chemical or a physical change has taken place, and whether the reaction was exothermic or endothermic.
Make sure to clean up all of your equipment and put everything back where you got it. The procedures may be down in any order
as long as all are done. Put previous materials away before starting a new one. EACH PROCEDURE IS A DIFFERENT ACTIVITY.
Research Question:
How can qualitative and quantitative observations be used to determine the type of change occurring within a system
(Chemical or Physical).
1.
Place a scoop (using a scoopula) of ammonium chloride into a clean test tube. Into another clean test tube place a scoop of
(using a scoopula) of calcium chloride. Add 3 mL of water to each and mix.
Do not place finger over test tube and shake to mix. Use a stirring rod or tap with your finger. Also never stopper and shake
(unless instructed otherwise by the instructor).
Feel the outside of the test tube for any temperature changes. Are there any similarities between them?
2.
Take a piece of pre-cut magnesium ribbon, and ignite it by holding it in the hottest part of the Bunsen burner flame. Note
its properties (color, luster, flexibility) before and after burning.
CAUTION:
3.
Do not look directly at the magnesium while it is burning.
Take another piece of pre-cut magnesium and place it into a clean test tube. Place this test tube into a test tube rack. Add
about 2 mL of hydrochloric acid to this test tube. While one person in the group is measuring out the acid, the other should
ready a burning splint to insert into the top of the test tube. Be thorough in your observations (rate of reaction, any
temperature change, etc). Can you name the gas that is evolved?
Caution:
Hydrochloric acid can cause severe burns. HANDLE WITH CARE. If you spill some on yourself or the lab station
put baking soda on it.
Chem 10
Brakke
ECA – Topic 01
4.
Into a clean test tube add 2 mL of sodium hydroxide solution. Place this test tube into a test tube holder. Add 2 mL of
copper (II) sulfate solution to the same test tube. Describe what happens.
Let set for 10-15 minutes, and again observe.
CAUTION:
5.
Do not put these chemicals down the drain. Place them in the waste container
in the fume hood.
Put one scoop (using a scoopula) of sodium bicarbonate (sodium hydrogen carbonate) into a clean dry test tube. Place this
test tube into a test tube holder also. Add 2-3 mL of acetic acid to this.
After about 10 seconds, place a burning splint into the top of the test tube (not into the liquid). Describe your observations.
6.
Fill the rounded bottom of a clean dry test tube with copper (II) sulfate pentahydrate.
Heat slowly and gently over a Bunsen burner. Hold the test tube in place using a utility clamp. Record observations before
and after heating
Let the test tube cool, and then add several drops of water to the cooled test tube. Record your observations.
CAUTION:
7.
Do not put these chemicals down the drain. Place them in the waste container
in the fume hood.
Mix 2.0 grams of iron fillings with 2.0 grams of sulfur in a mortar and pestle. Place on a sheet or partial sheet of white
paper, and place a magnet underneath the paper. Record your observations.
Dispose of the iron fillings and sulfur in the receptacle on the demonstration table in the front of the room.
Physical and Chemical Changes Lab Activity
Grading Criteria:
o
DCP – Data Collection and Processing
C P N n/a • Use of vocabulary learned in class
C P N n/a • Raw quantitative data (or statement of none)
C P N n/a • Qualitative observations
C or Zero • All data is collected individually (non-negotiable)
C P N n/a • Tables contain title, headings, explanations
C P N n/a • Units are present and correct throughout (if quantitative)
C P N n/a • Tables are organized and easy to follow
CE – Conclusion and Evaluation
C P N n/a • Results are repeated at beginning
C P N n/a • State the type of process occurring (Chemical or Physical)
C P N n/a • Restate and respond to the research question
C P N n/a • Conclusion is based on your results (specifically)
C P N n/a • New Equipment Necessary to test Quantitatively (or more precise)
C P N n/a • Manipulation of procedures (and why)