OBJECT:
To study the size of molecules and how they behave.
MATERIALS:
Large jar, ( Which will serve as your large beaker), Small seasoning containers ( Like the one used in making a graduate cylinder, National brand ( McC...) labeled 1.75 oz Net WT) This will hold 100 ml. (Note: All spices are irradiated, and the law permits them, not to label it as such), Salt, and Food coloring. Freezer or a bag of crushed ice.
PROCEDURE AND OBSERVATION:
(Part A )
1. Obtain a large plastic soda bottle, if it is possible, remove the label which may be plastic like paper, from the container. Rinse it out and fill it with hot tap water ( Use CAUTION when handling hot tap water.) let stand for about five minutes. Empty the bottle, but make sure that there is some small quantity of water inside. Secure the cap, nice and tight, with out squeezing the bottle. Place it into the freezer for about 15 to 20 min. and proceed to part B. ( If you are doing this for a class demonstration, and there is no freezer, then buy a bag of crushed ice.) Find a container to place the soda in and surround the bottle.
2. Proceed to part B.
(Part B)
1. Pour salt into the small spice container until it is 3/4 full and mark the level with tape or marking pen. ( The label does not have to be removed from the spice container, just remove as much as need it, to see the level of the contents.)
2. Fill a large jar with water to the brim.
3. Now, see how much salt you can sift, into the jar before the water runs over the edge.
4. Record the amount of salt used. Make a second mark on the small container.
5. Clean up.
(Part C)
1. Obtain 3 small jars and label them. ( good source of small jars would be baby food jars ) ( Fill all to the same level, say up to the shoulder of the small jar.)
2. Fill the first small jar with cold ice water.
3. Fill the second beaker with room temperature water. (Be sure to do this ahead of time, let the water stand for about half an hour)
4. Fill the third small jar with hot tap water. (Remember Safety First, some tap water can be very hot, so use CAUTION!)
5. Obtain a thermometer and record the temperature of each beaker. ( If you do not have a thermometer, use the thermostat thermometer reading and then convert to Celsius)
6. Add a drop of food coloring to each beaker. Record the time required for complete mixing in each beaker.
QUESTIONS:
1. In part B of the experiment could you see the salt crystals in the water?
2. How do you think the particles of dissolved salt compare in size with the crystals with which you started?
3. What answer does the considerable amount of salt you were able to dissolve suggest to the question whether water has space between its particles or not?
4. In part C what relationship do you find between temperature and the speed of mixing?
5. In part B and C was there a chemical or a physical change? Explain your answer.
6. In part B and C was there a compound or mixture produced? Explain your answer.
7. To go from a solid to a liquid you need________. To go from a liquid to a gas you need___.
8. Describe the motion of a molecule in a solid, liquid, and a gas.
9. Describe the forces of attraction between a molecule in a solid, liquid and a gas.
10. What is the relationship between forces of attraction, heat energy and motion of a molecule?
11. Define boiling point.
12. At what temperature does water boil, at see level, on the Celsius scale?
13. Explain how it is possible to change the boiling point of water.
14. Is it true that boiling point of water is a quantitative physical property?
15. Explain why the plastic bottle got smaller in size, when it was removed from the freezer?
16, State the Kinetic Molecular Theory.
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