DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE SOLIDS, LIQUIDS, GASES I – SOME PROPERTIES 1. Discuss the properties in the table that you know for solids, liquids, and gases with your partners and fill in the blanks with the appropriate word or phrase. SOLIDS LIQUIDS SHAPE (Definite or Indefinite?) VOLUME (Definite or Indefinite?) POURABILITY (Yes or No) GASES *see part (B) 2. To help you answer the pour ability question about gases, you can easily make some carbon dioxide and see if you can pour it. Place two full spatulas of sodium bicarbonate in a beaker. Add about ½ inch of vinegar. Cover the beaker with a glass plate. Light a candle and place it on the lab table. Lift the covered beaker over the lit candle, remove the glass plate and carefully “pour” only the CO2 onto the candle. Record your observations. 3. Give the name associated with the following changes in state and give a common example of each kind of change. NAME EXAMPLE SOLID TO LIQUID LIQUID TO GAS SOLID GAS GAS TO SOLID LIQUID TO SOLID GAS TO LIQUID 4. Can all material things exist in any of the three states of matter? Explain your answer. 1 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE SOLIDS, LIQUIDS, GASES II - COMPRESSIBILITY In this activity, you will squeeze each of the three states of matter to see how they behave. We can learn about the tiniest bits of matter, even though we can’t see atoms and molecules, from how large amounts of matter behave. Before you begin, do you think it’s possible to compress each of the three states of matter? Please talk it over with your partners and put your prediction and the reason(s) you think so in the space provided below. SOLIDS LIQUIDS GASES 1. Take a large syringe, remove the plunger, and fill it halfway with the solid provided. Replace the plunger, point the tip upward and gently push the plunger to expel the air. Tap down on the solid to make sure it is firmly packed. Rest the open end of the syringe on a cork to prevent the solid from running out. Once again gently push on the plunger. What happened to the volume (space occupied) by the solid as pressure was applied? ___________________________________________________________________ 2. Remove all solid from the syringe. You may have to clean out the syringe a bit by using a twisted paper towel. Push the plunger all the way down and place the tip of the syringe into a beaker of water. Pull up on the plunger until the syringe is ½ filled with water. Get rid of any air bubbles by pointing the tip upward and pushing the plunger. Place the tip of the syringe on the cork and push gently on the plunger. If water squirts out then you are pushing too hard. What happened to the volume of the water as pressure was applied? ____________________________________________________________________ Were you able to compress the liquid? __ 3. Empty the water. Now your syringe is filled only with air. Press the plunger down the halfway point then stopper it by placing the tip against a cork on the table. Gently push down on the plunger. What happened to the volume of air as pressure was applied? ____________________________________________________________________ Were you able to compress the gas? _ 2 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE Although we cannot see atoms (even with a microscope), based on what you just did, what can you theorize (make an explanation) about some differences in the spaces between particles (atoms and molecules) of solids, liquids, and gases. What do you think is in the space between particles? 3 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE BREAKING INTO SOLIDS, LIQUIDS, GASES 1. Dry an ice cube with a paper towel and place it on a watch glass. Gently place two drops of food coloring on the ice cube. What do you observe? __________________________________________________________________ Draw a picture of what you see. 2. Fill a 250 mL clean beaker with tap water. Let it sit on the lab table undisturbed for one minute. Gently place two drops of food coloring on the surface of the water. What do you see immediately? What do you see after 1 minute? What do you see after 3 minutes? In the space below draw three pictures representing the beaker at the three time intervals. IMMEDIATELY 1 MINUTE 3 MINUTES What can you theorize about the differences between the particles of solids and liquids based on what you saw? 4 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE 3. Have the members of your group space themselves in a line about nine feet long. You can all go out in the hallway for this activity. Try to find a place where there are not a lot of drafts or people walking by. Have the first person in line hold a bottle of solid air freshener and open the top.. Time how long it takes for each person in the line to smell the air freshener. Everyone should stay as still as possible while this is taking place. SECONDS PERSON #1 PERSON #2 PERSON #3 What must be true about particles of gas based on your observations? 5 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE SKIMMING THE SURFACE Water, water everywhere – and it’s such an interesting liquid! 1. Take a small test tube and fill it to the very top with tap water. How many drops of water do you think you can add before the water will spill over? Using an eyedropper continue to add water drop by drop, counting as you go, until the water spills. Number of drops needed Describe what you saw as you were adding the drops of water. 2. Clean a penny with soap and water and place it on the lab table. How many drops of water do you think you can place on the penny before the water will spill onto the table? Your predicted number of drops The actual number of drops 3. Fill a small beaker with water. Very carefully lay a headless pin or aluminum paper clip sideways on the surface of the water. It might help to use tweezers to place the pin. Observations Place the needle point first into the water. Observations From the above three activities, what seems to be true about the surface of the water? 6 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE 4. Which will evaporate more easily a beaker of hot water or a beaker of cold water? Why do you think this is so? What does “evaporation mean? How is evaporation different from “boiling?” 5. Place a few drops of water on the lab table and a few drops on a piece of waxed paper. Describe what you see? Do you think water molecules are more attracted to each other or to wax molecules? Explain your choice. Do you think that water molecules are more attracted to each other or to the molecules of the table? Explain. Are there any questions you would like to ask? 7 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE DISCOVERING THE SHAPE OF CRYSTALLINE SUBSTANCES View the various available household substances under a microscope or magnifying glass. Describe or illustrate the shape of the crystals. Substance Epsom salt – magnesium sulfate Description or Illustration Table salt – sodium chloride Sucrose – table sugar Hypo -sodium thiosulfate (used in photography) Note: Some common household chemicals such as baking soda, baking powder, and alum are powdered substances and the crystals are too small to see with a low powered microscope. 8 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE ALUMINUM CAN PLAYTIME A B C 1. If figure A represents an open aluminum can sitting on the lab table, and Pi is the pressure of the air inside the can, and Po is the pressure outside the can, then do you think: Pi = Po or Pi > Po or Pi < Po? Explain the choice. In figure B, the can is being crushed. Which condition do you think exists? Pi = Po or Pi > Po or Pi < Po? Explain the choice. In figure C, the can is exploding. Which condition do you think exists? P1 = PO or P1 > P O or P1 < PO Explain the choice. 2. a. Place a small amount (about 5 mL) of water into an aluminum can. b. Place the can on a hot plate, set on high, and heat until the water is boiling and steam is clearly escaping. Let it boil for about 1 minute, but do not allow it to go to dryness. c. Using tongs, quickly invert the can into icy cold water. d. Describe what happened. e. Which of the following condition occured? Pi > Po f. or Pi < Po? Can you think of a possible explanation for the result? 9 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE WHAT WOULD HAPPEN IF THERE WAS NO AIR? The world we live in is filled with air. Air is a mixture of gases. We are not always aware that the air is there because we cannot see it. But, we can feel the air when the wind blows. The apparatus at this station is a vacuum pump. It will suck the air out of the heavy glass chamber called the bell jar. You are going to place some items into the bell jar and see what happens to them when the air is taken away. Vacuum pump and bell jar Bell jar 1. Blow up a little balloon so it about the size of your closed fist and tie it off with a knot. Take a marshmallow out of the bag. Shake up the can of shaving cream and squirt a small amount into a 100 mL beaker. 2. Now carefully slide the bell jar off the metal platform of the vacuum pump. The contact point of the bell jar and the platform should be coated with grease to insure a good seal. Place the balloon, marshmallows, and shaving cream on the platform. Place the bell jar over these items. In the space below draw a little picture of the items in the bell jar. Now turn the switch and suck the air out of the bell jar. Wait about two minutes then draw another picture of the items that you put into the bell jar. 10 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE WITH AIR WITHOUT AIR What happened to the balloon, marshmallows, and shaving cream when the air was removed from the bell jar? What does this result tell you about air? 11 DAY 5 CHEMISTRY SUMMER SCIENCE INSTITUTE 12