Experiment 4
Physical and Chemical Properties
Pre-Lab
Make an outline or drawing or flow chart of the procedures below using your own words. You will not be able to start the lab unless you have this pre-lab done.
Procedure
1. You will find the following substances in glass jars: sulfur, iron, sodium bicarbonate, sodium chloride, sucrose and sand. You can obtain a piece of magnesium from the teacher. Test the effect of a magnet on each of the 7 substances. Run the magnet along the side of the glass. Do not dip the magnet into the glass jar. For the magnesium, just touch it directly to the magnet. Record your observations.
2. Test the solubility of each of the 7 substances in water. Add a small amount of each substance to separate test tubes (get from teacher) using the spatula and add 3 ml of water (use the graduated cylinder to measure) to each test tube. Mix each sample by gently flicking the tube, and/or using a stirring rod. (Your teacher will give you the sulfur and iron.) Record your observations. Empty dirty test tubes containing sulfur, iron, and sand in the respective disposal beakers! Do not dump these down the sink, and return these dirty tubes to the teacher. You may empty the test tubes containing sodium chloride, sodium bicarbonate, and sucrose in the sink and clean these test tubes.
3. On a piece of weigh paper (get from teacher), and your teacher will give you a small amount of iron and a small amount of sulfur (using the spatula). Mix the samples. Move a magnet under the paper. Record your observations. What kind of mixture did you make?
4. On another piece of paper combine a small amount of sodium chloride and a small amount of sand. Test the effect of a magnet like above. Record your observations. What kind of a mixture did you make?
5. Transfer the sand and salt mixture to a 100 mL beaker and add 30 mL of water. Filter the mixture using a piece of folded filter paper in a glass funnel. Put the funnel in the ring stand and place another 100 mL beaker just below it. Pour the mixture through the filter paper in the funnel and allow the "filtrate" to drip into the beaker below. When it has completed, observe the filter paper and then throw it away and rinse off the funnel.
6. Now that you have a filtrate, put the 100 mL beaker containing the filtrate on a wire gauze supported by the iron ring on the ring stand. Using the gas burner, heat the liquid until the water has completely evaporated. Turn off the burner and do not touch the beaker until it has cooled completely. Observe what is inside the beaker. If you need to move it use the tongs. Record your observations. Clean the beaker out when it is cool.
7. UNDER YOUR TEACHER’S SUPERVISION, now you will obtain a piece of magnesium from your teacher, and you will burn magnesium, under your teacher’s supervision! Use the tongs to grab onto one piece of magnesium. Turn on your burner and hold your piece of magnesium into the flame until it ignites. DO NOT LOOK DIRECTLY AT BURNING MAGNESIUM! It produces a blinding light. Look at the flame through a piece of blue glass. Catch the combustion product (burned magnesium) on a watch glass. Record your observations.
8. Put the combusted magnesium product into a test tube. Put a new piece of magnesium into another test tube. Carefully add 10 drops of hydrochloric acid to each tube. BE CAREFUL WHEN USING THIS ACID! IT WILL BURN YOUR SKIN AND CLOTHING! Record your observations. Bring your test tubes back to the teacher.
9. ONLY ONE GROUP WILL DO THIS PART OF THE EXPERIMENT UNDER YOUR TEACHER’S SUPERVISION, AND THIS GROUP WILL SHOW THE REMAINDER OF THE CLASS THE RESULTS. Put a small amount of sucrose sample into a clean dry test tube. Heat the tube with a flame using a test tube holder and being careful to point the tube away from any people. Watch the tube carefully for changes to the sugar. Record any observations. Be sure that the test tube is cool before touching. Bring it to the teacher for the dirty dishes tray.
NOTE: An important part of your lab grade is whether you left your lab station the way you found it, with all glassware cleaned and materials disposed of properly!!!!
CONCLUSION/ QUESTIONS:
1. State in your own words the difference between chemical and physical properties. Which parts of this lab showed physical properties and which parts showed chemical properties?
2. State in your own words the difference between chemical and physical changes. Which parts of this lab showed physical changes and which parts showed chemical changes?
3. State in your own words the law of conservation of mass. Where did you see this law exhibited in this lab?
You will write a formal report for this lab, using your lab report guidelines.
Due: ______
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