Conclusions: 1. What happens to the volume of the gas inside the dropper as you put pressure on the container?

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1 Gas Stations Chemistry Gas Station 1 Pressure Purpose: To observe the affect of pressure of a gas Safety: Wear goggles and aprons!!! Obtain an empty canister. Fill it half way with water and ½ an alka seltzer tablet. Place the lid and the canister and stand back. Record your observations. Repeat twice with varying amounts of water. Amount of water 10 ml ml ml 1. Which volume of water gave the biggest pop? 2. What is the purpose of the effervescence (fizz) in an antacid tablet? Gas Station 2 Pressure and volume Purpose: To compare the affects of pressure on the volume of a gas Obtain an eyedropper and a water bottle filled with water. Fill the dropper half full of water. Place the dropper in the water bottle and screw on the top. Squeeze the closed water bottle and record your observations. 1. What happens to the volume of the gas inside the dropper as you put pressure on the container? 2. Why does the dropper sink? 3. What happens to the volume of air inside a container as pressure increases? 4. Explain how this affect is similar to your ears popping in an airplane that s landing or diving under water. Gas Station 3 Pressure, volume and temperature Purpose: To compare the affects of pressure and temperature on the volume of a gas Safety: Wear goggles and aprons!!! Place 10 ml of water in a clean, empty soda can. Heat the can until you begin to see steam rising out of the can. Quickly turn the can completely over into the water (upside down) in a container of cold water. Record your observations. 1. What happened to the can? 2. Explain why this happens. 3. What happens to the volume of a gas as temperature decreases? 4. What happens to the volume of a gas as the pressure increases?

2 Gas Station 4 Boyle s Law Purpose: To compare the affects of pressure on the volume of a gas. Obtain a sealed pipet containing colored water and a metric ruler. Use a ruler to record the volume of the air in the pipet. (The empty stem) Place one chemistry book on the bulb of the pipet and record the volume of the air. Repeat with two books, three books, four books and five books. Make a graph of volume vs. number of books. Number of books Volume of air (mm) Draw your graph of volume of air (mm) vs. number of books. 2. What happens to the volume of a gas as pressure increases? 3. What is the definition of Boyle s law? 4. What is the formula for Boyle s law? 5. Use your graph to predict the volume of air with 6 books. Gas Station 5 Charles Law Purpose: To compare the affects of temperature on the volume of a gas. Safety: Wear your safety goggles!! Use flask tongs to handle hot glassware. Record the volume of air in an empty small Erlenmeyer flask (V1) the volume of air is the size of the flask) Stopper the flask and heat it in a hot water bath for 5 minutes. Take the temperature of the hot water bath (T1) Use flask tongs to turn your hot flask over into a beaker of cold water. Take the temperature of the cold water bath (T2) Read the volume of air remaining in the cooled flask. (V2) (Measure the water and subtract from the size of the flask) Measurement Initial volume of flask (V1) Initial temperature of the flask (T1) Final volume of flask (V2) Final temperature of flask (T2) 1. Draw your graph of volume of air vs. temperature of the air (temperature in Kelvin)

3 2. What happens to the volume of a gas as temperature increases? 3. What is the definition and formula for Charles law? 4. Use your graph to predict the volume of air at 273K Gas Station 6 Atmospheric Pressure Purpose: To observe the affects of atmospheric (air) pressure on a container. Obtain a trick bottle. Make as many observations of your sealed bottle as you can. Open the lid of the bottle. (Caution- hold it over the sink!). Record your observations. Fill a mason jar completely with water. Place a notecard on top of the jar. Hold your hand over the card and quickly turn the jar upside down over the sink. Record your observations. Tilt the jar slightly. What happens? Trick bottle - Sealed Trick bottle- Unsealed Mason jar - upside down Mason jar - tilted 1. Define pressure. 2. What is a barometer? 3. Would a change in the pressure affect the rate of flow of either container? 4. Write a practical use for this experiment. Gas Station 7 Diving Submarine Purpose: To observe the density of a gas Open the top hatch of a diving submarine. Fill the compartment on the diving sub with baking powder. Secure the compartment on your sub. Place your sub in a container of water. Record your observations. Repeat using no baking powder. Record your observations. Submarine with baking powder Submarine with no baking powder 1. Give a reasonable explanation of the behavior of the submarine. 2. What affect does baking powder have as a cooking ingredient? What happens to a cake if baking powder is omitted from the recipe?

4 Gas Station 8 Pressure and Volume Purpose: To observe the affects of pressure on volume of various items Place a small tied balloon in a syringe. Seal the syringe by covering the opening with your finger. Observe the affects of increasing and decreasing pressure on the syringe. Record your observations. 1. What is the effect of increasing pressure on the volume of a gas? 2. What is the effect of decreasing pressure? 3. Which gas law does this illustrate? 4. Write the equation for this gas law. Gas Station 9 Using the Kelvin scale Purpose: To convert temperatures to Kelvin Look up the conversion to Kelvin from Celsius in your textbook. Record the temperature of the room in both Celsius and Kelvin. Record the temperature of an ice water bath in both Kelvin and Celsius. Temperature Room Temperature in Celsius Room temperature in Kelvin Ice bath in Celsius Ice bath in Kelvin 1. What is the conversion from Celsius to Kelvin? 2. Why do we use the Kelvin scale in calculating gas laws? 3. Perform the following problem: V1/T1 = V2/T2 V1 = 100 ml T1 = -10*C V2 = X T2 = 100*C Be sure to change your temperatures to Kelvin. Gas Station 10 Affect of temperature on the volume of a gas Purpose: To observe the affect of temperature on volume of a gas. Safety: Wear your goggles and aprons! Handle hot glassware with care. Heat a small flask in a hot water bath. Remove the flask with flask tongs. Carefully place a balloon on the mouth of the flask. Quickly place the flask in a cold water bath and record your results.

5 Hot flask with balloon Cold flask with balloon 1. What was the effect of changing the temperature on your balloon? 2. What gas law does this illustrate? 3. Write the definition of this gas law. 4. Write the formula for this gas law. Gas Station 11 Definitions Define the following terms: 1. Standard temperature 2. Standard Pressure 3. Barometer 4. Atmosphere 5. Absolute zero 6. Ideal gas law 7. Ideal gas constant 8. Diffusion 9. Effusion Answer the following questions: 10. What are the values for STP? 11. What is the molar volume of a gas at STP? 12. Write the formula for Boyles Law 13. Write the formula for Charles Law 14. Write the formula for Gay Lussac s Law 15. Write the formula for the Ideal Gas Law

6 Gas Station 12: Complete the following worksheet: Boyle s, Charles, Gay-Lussac s, and Combined Gas Law Worksheet Solve all problems you must show your work (including units). The correct answer is given in parentheses at the end of the problem. Boyle s Law 1. A gas sample contained in a cylinder equipped with a moveable piston occupied ml at a pressure of 2.00 atm. What would be the final pressure if the volume were increased to ml? (1.2atm) 2. A balloon that contains 1.50 L of air at 1.00 atm is taken underwater to a depth at which the pressure is 3.00 atm. Calculate the new volume of the balloon. Assume that the temperature remains constant. (0.5L) 3. A 50.0 ml sample of gas collected in the upper atmosphere at a pressure of 18.3 torr is compressed into a ml container at the same temperature. What is the new pressure? ( 6.10 torr) 4. A sample of krypton gas occupies 75.0 ml at atm. If the temperature remained constant, what volume would the krypton occupy at 4.00 atm? (7.5mL) Charles Law 5. Several balloons are inflated with helium to a volume of 0.75 L at 27 C. One of the balloons was found several hours later, the temperature had dropped to 22 C. What would be the volume of the balloon when found, if no helium has escaped? (0.74L) 6. A weather balloon is filled to the volume of L on a day when the temperature is 10 C. If no gases escaped, what would be the volume of the weather balloon after it rises to an altitude where the temperature is -8 C? (140.5L) 7. A fixed quantity of gas at 23 C exhibits a pressure of 748 torr and occupies a volume of 10.3 L. Calculate the volume the gas will occupy if the temperature is increased to 145 C while the pressure is held constant. (14.5L) 8. A sample of gas occupies a volume of 7.50 L at atm and 28.0 C. At what temperature, in degrees Celsius, is the volume of the gas 4.00 L if the pressure is kept constant. ( C) 9. A gas occupies a volume of ml at 27 C and torr. At what temperature, in degrees Celsius, would a volume of 50 ml be at torr? (-123 C)

7 Gay-Lussac s Law 10. A sample of gas occupies 10.0 L at torr and 27 C. Calculate the pressure if the temperature is changed to 127 C while the volume remains constant. ( torr) 11. The temperature of ml of a gas originally at STP is changed to -25 C at constant volume. Calculate the pressure of the gas in atm. (0.91atm) 12. A gas occupies a volume of 50.0 ml at 27 C and 630 mmhg. At what temperature, in C, would the pressure be 101.3mmHg? (-224 C) 13. A sample of gas occupies a volume of 5.00 L at 700 mmhg and 30 C. At what temperature, in C, would the pressure be 600 torr if the volume remains constant? (-13.3 C) 14. A sample of gas is at STP. Under what pressure would it be if the temperature were increased to 819 C? (4.0 atm) Combined Gas Law 15. A ml sample of neon exerts a pressure of torr at 26 C. At what temperature, C, would it exert a pressure of 940 torr in a volume of ml? ( C) 16. A certain gas has a volume of ml at 77 C and torr. Calculate the temperature, C, if the volume decreased to ml and the pressure is increased to 1.00 atm. (81.67 C) 17. A given sample of gas has a volume of 4.20 L at 60.0 C and 1.00 atm pressure. Calculate its pressure if the volume is changed to 5.00 L and the temperature to 27 C. (0.76atm) 18. A gas has a volume of 240.0mL at 25 C and mmhg. Calculate its volume at STP. (173.58mL) 19. A certain gas occupies a volume of ml at STP. What would its volume be at 27 C and 12.0 atm? (50.4 ml)