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Kinetic Theory of Matter Gas Laws. Engage- Pressure & Volume 1. Observe a “Cartesian Diver”. Record your observations.

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Presentation on theme: "Kinetic Theory of Matter Gas Laws. Engage- Pressure & Volume 1. Observe a “Cartesian Diver”. Record your observations."— Presentation transcript:

1 Kinetic Theory of Matter Gas Laws

2 Engage- Pressure & Volume 1. Observe a “Cartesian Diver”. Record your observations.

3 Investigate Day 1  Set up a syringe (as shown) that can be placed on a support and on which you can balance several books (or other masses). You can use the weights of the books as a measure of the pressure or you may use a pressure sensor and probeware. (Follow the instructions give with your probeware and associated software.)  a) For each pressure, record the volume of the gas.  b) Make a graph of volume versus pressure, or view the graph produced by your probeware.  2. Based on the graph of volume vs. pressure, decide what kind of mathematical relationship you think exists between these two variables, direct or inverse. (Reminder: In a direct relationship, as the pressure increases, the volume increases. In an inverse relationship as the pressure increases, the volume decreases.)  3. In the experiment, you varied the pressure and recorded volume. You could have changed the volume and measured the pressure required to maintain that volume. This would be equal to the pressure of the gas.

4 Analysis  1. Using your data, graph the pressure (number of books) and volume and pressure and 1/volume.  a) Sketch a graph that shows a direct relationship between two variables.  b) Sketch a graph that shows an inverse relationship between two variables.  c) Which of your graphs best depicts the relationship between pressure and volume? Explain.  2. What is the mathematical relationship for pressure and volume of a confined gas at constant temperature?  3. Define pressure.  4. What units are used to measure pressure?  5. What units are usually used to measure the volume of a gas?

5 Explain- Pressure & Volume  Read pp and and answer the following questions:  1. State Boyle’s Law.  2. Give two practical applications of Boyle’s Law.  3. Divers get “the bends” if they come up too fast because gas in their blood expands, forming bubbles in their blood. If a diver has gas in his blood under a pressure, then rises instantaneously to a depth where his blood has a pressure is less, do you think this will harm the diver?  4. Submarines need to be extremely strong to withstand the extremely high pressure of water pushing down on them. What would happen if the submarine dove to a very low depth such as the ocean floor?  5. Why must the water be heated to at least boiling when home canning foods?  6. How did the pressure inside the canning jar become lower than the pressure outside the canning jar?  7. Why is the air pressure on top of a high mountain less than the air pressure at sea level?

6 Engage- Pressure & Temperature

7 Investigate Day 3  1. Add a marble to an empty film canister. Add 2 mL of water. The marble serve the purpose of preventing the film canister from tipping over and floating. They do not participate in the chemical reaction.  2. Grind up some effervescent antacid tablets in a mortar with a pestle. Weigh out 0.5 g of the powder and then add it to the film canister.  3. Quickly snap on the lid, place it on the table, and step back.  a) Record how long it takes before the lid pops off.  4. Continue to alter the amount of powder until the lid remains on the canister for a period of between 25 and 35 s (seconds) before popping. That means that it can’t pop before 25 s, but it may pop before 35 s Examine the contents left in the film canister. There should not be any white solid remaining. If there is, reduce the amount of effervescent antacid tablets and try again. (You must empty out the contents of the canister and wipe it dry before repeating the experiment.)  5. Using the same canister, marble, and volume of water as in Step 4, place the canister in a flat-bottom dish. Pour cold water in the dish to surround the canister to within 1 cm of its rim. You might want to add some ice to cool the water down to a temperature at least 15°C lower than the room temperature. Repeat the experiment using the cold water.

8 Investigate  You might choose to use a table similar to the one shown below to keep track of your data. TrialTrial Mass of Antacid Tablets (mg) Temperature of water ( °C) Time it Takes Top to Pop (s)

9 Analysis  1. What are two factors that account for a gas’s pressure?  2. How are the temperature and average rate of motion in a gas related?  3. Describe how the pressure inside a film canister changed when temperature increased.  4. Is the relationship between pressure and temperature a direct or indirect relationship?  5. What is the mathematical relationship for pressure and temperature of a confined gas at constant volume?

10 Explain- Pressure & Temperature  Read pp and answer the following questions.  1. What happens to the pressure inside an automobile tire when the winter arrives and the temperature drops?  2. Read the label on two aerosol cans concerning safety and cautions with heat. What temperature is mentioned on the cans? What happens if you exceed that temperature?  3. Dissolved oxygen in a lake or pond is important for fish to survive. What happens to the solubility of oxygen when the temperature gets much hotter in the summer?  4. Why have fountains been installed in some newly made lakes and ponds at apartment complexes, subdivisions, and golf courses?

11 Engage- Volume & Temperature What allows the balloons to function? (How does it work?)

12 Investigate Day 6  1. Completely fill an empty pipette with water.  2. Count and record the number of drops it takes to empty the pipette. This number represents the volume of the pipette. It also represents the volume of gas at room temperature in the empty pipette in this activity. Record this as the volume of the empty pipette.  3. Half-fill a 600 mL-beaker with H 2 O (approximately 20ºC).  4. Half-fill a second 600 mL-beaker with water and place it on a hot plate. Place a thermometer in the beaker.  5. Turn the hot plate on and begin heating. Continue heating until the water reaches the temperature assigned to your group by your teacher.

13 Investigate  6. Use tongs to hold the bulb of the pipette under water in the beaker being heated. The stem of the pipette should be above the water level. Keep the pipette immersed for 3 minutes. After 3 minutes, squeeze and seal the tip of the pipette with tweezers. Then lift the pipette out of the water. Quickly transfer the pipette to your room temperature water bath and completely submerge the pipette bulb and stem and removing the tweezers. Hold it in place with your tongs.  7. Notice that water is entering the pipette. Keep the pipette submerged until no further changes are noted (about 1 minute).  8. Remove the pipette from the water and dry the outside. Count the number of drops of water that were drawn into the pipette. Subtracting the number of drops of water from the total volume of the pipette (found in Step 2) gives you the volume of the air at 20ºC.  9. Repeat these measurements three times. Calculate and record the average.

14 Analysis  1. Using your data, graph the average number of drops and the temperature at room temperature and the heated temperature.  a) Sketch a graph that shows a direct relationship between two variables.  B) What is depicted as the relationship between temperature and volume? Explain.  2. Using a ruler, extend the line of your graph to the axis. What is the temperature?  3. What is the mathematical relation between volume and temperature?

15 Explain- Volume & Temperature  Read pp and answer the following questions  1. How do the moving gas particles in a canister exert pressure? Explain using the Kinetic Molecular Theory of Gases.  2. With a fixed mass of a gas, the Kinetic Molecular Theory describes the relationship among which three variables?  3. What problems would you encounter in your calculations if you did not convert the Celsius temperature to the Kelvin scale?  4. How might the temperature in the gym affect the volume of a basketball and thus its bounce?  5. Predict the effect of hot temperatures on car tires. Will they appear fuller or flatter? Predict the effect of cold temperatures on car tires. How will their appearance change? Explain your answer.  6. In a hot-air balloon, the balloonist may have to light the propane torch for a few minutes. Using Charles’s Law, explain why he might need to do this.

16 Evaluate  Choose two of the following activities to complete.  1. Write a ½ page describing each of the following: Boyle’s law, Charles’ law, and Guy Lussac’s law. (You must do this one)  2. Draw a venn diagram or Thinking Map of the gas laws and how they are related to each other.  3. Create a cartoon using the gas laws.


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