Introduction to Gas Laws Lab NAME: DATE: PERIOD:

Transcription

1 Introduction to Gas Laws Lab NAME: DATE: PERIOD: Background: In a gas, particles are spread far apart; therefore a gas takes up more volume than a solid or a liquid. For example, water in the form of steam takes up about 2000 times the volume that the same amount of water does in liquid form. There are many formulas to describe the behavior of a gas under certain conditions. Boyle s Law, PV=k, states that the pressure is inversely proportional to the volume. Charles s Law, V/T =k, states that volume is directly proportional to the temperature. Gay-Lussac s Law, P/T =k, states that pressure is directly proportional to the temperature. Relationships that are directly proportional produce a straight line graph, while inversely proportional relationships produce a curve. Applying these laws to compare gases under two different sets of conditions gives the formulas: P 1 V 1 =P 2 V 2, V 1 /T 1 =V 2 /T 2, P 1 /T 1 =P 2 /T 2. These three laws together give the Combined Gas Law: P 1 V 1 /T 1 =P 2 V 2 /T 2. Procedure & Observations: Part 1 1) Obtain a large beaker ( ml) and fill 3/4 full of tap water. 2) Obtain an aluminum can and add 7-10 milliliters of water. 3) Place the can on a heating set up (hotplate or wire gauze/ring stand) and heat until a steady stream of steam flows out of the can. 4) Using beaker tongs, grab the aluminum can near the bottom of the can and quickly turn it upside down into the beaker of water. When the can was heated, the water turned to, which takes up (more/less) volume than liquid water. When the can was inverted into the water this created a closed system. The temperature inside the can (increased/decreased), causing the steam to change from gas state to state. A partial vacuum was created causing the pressure inside the can to be (greater/less) than the pressure outside the can. Part 2 1) Obtain a small balloon filled with air. Submerge the balloon in a large beaker of ice water and hold for 3 minutes. Use beaker tongs to keep the balloon submerged. Observe. 2) Transfer balloon to large beaker of hot water and submerge for 3 minutes. Observe. As the water temperature increased, the volume of the balloon. This is an example of Law.

2 Part 3 1) Obtain a 250-mL Erlenmeyer flask and place milliliters of water inside. 2) Place the flask onto a heating setup (hotplate or wire gauze/ring stand) and heat until a steady stream of steam comes out. DO NOT let the water boil away. 3) Take the flask off of the gauze using flask tongs. 4) While holding onto the neck of the flask using flask tongs, have a lab partner stretch the mouth of a large balloon over the mouth of the flask. Make sure the balloon is centered on the opening of the flask. This creates a closed system. 5) Wait 2-3 minutes and observe. Then place the flask into a beaker of ice water. Placing the balloon over the mouth of the flask created a system. As the in the flask dropped the steam turned to water. Since water in the liquid state takes up less than water in the gas state, a partial vacuum was created. The greater outside of the flask pushed the balloon inside. Part 4 1) Obtain a 1000 ml beaker / candle set-up. 2) Fill the beaker with water until the water level is halfway up the candle. Light the candle. 3) Carefully invert a 1000 ml Erlenmeyer flask over the candle. Observe both candle and the water level. Propose an explanation: Conclusion: 1) Give the name of the law that relates pressure to volume. 2) Give the name of the law that relates volume to temperature. 3) The condensing of steam in a closed system creates a partial. 4) If the volume of a gas is cut by 1/2, the pressure will (increase/decrease) by a factor of (2, 1/2) times. 5) If the temperature of a gas is doubled, the volume of the gas will (increase/decrease) by a factor of (2, 1/2) times. 6) If the temperature of a gas is tripled, the pressure of the gas will (increase/decrease) by a factor of (3, 1/3) times. 7) Graphing pressure vs. volume would produce a. 8) Graphing volume vs. temperature would produce a line.

3 Teacher Notes: Introduction to Gas Laws Lab At each lab station: Two Large beakers (600mL or 1000mL) Aluminum can Hotplate or wire gauze, ring stand, burner and striker Beaker tongs Small filled balloon-must be small enough to fit in large beakers 250-mL flask Flask tongs Medium size balloon 1000-mL flask Candle set-up: A 1000-mL beaker with a candle in the center with aluminum foil surrounding the base of the candle to keep it stable and centered. At a central location: Container of ice Lighter-This item may be best if kept with the teacher and the teacher comes around and lights each candle. Teaching Tips: This lab is a series of demonstrations that were put together for the student s enjoyment. The students are surprised by the can being crushed and will many times ask for another can to repeat the experiment. This lab will take the student about 50 minutes to complete.

4 Introduction to Gas Laws Lab NAME: DATE: PERIOD: Background: In a gas, particles are spread far apart; therefore a gas takes up more volume than a solid or a liquid. For example, water in the form of steam takes up about 2000 times the volume that the same amount of water does in liquid form. There are many formulas to describe the behavior of a gas under certain conditions. Boyle s Law, PV=k, states that the pressure is inversely proportional to the volume. Charles s Law, V/T =k, states that volume is directly proportional to the temperature. Gay-Lussac s Law, P/T =k, states that pressure is directly proportional to the temperature. Relationships that are directly proportional produce a straight line graph, while inversely proportional relationships produce a curve. Applying these laws to compare gases under two different sets of conditions gives the formulas: P 1 V 1 =P 2 V 2, V 1 /T 1 =V 2 /T 2, P 1 /T 1 =P 2 /T 2. These three laws together give the Combined Gas Law: P 1 V 1 /T 1 =P 2 V 2 /T 2. Procedure & Observations: Part 1 1) Obtain a large beaker ( ml) and fill 3/4 full of tap water. 2) Obtain an aluminum can and add 7-10 milliliters of water. 3) Place the can on a heating set up (hotplate or wire gauze/ring stand) and heat until a steady stream of steam flows out of the can. 4) Using beaker tongs, grab the aluminum can near the bottom of the can and quickly turn it upside down into the beaker of water. The can was crushed when placed into the beaker of water. When the can was heated, the water turned to steam, which takes up _more (more/less) volume than liquid water. When the can was inverted into the water this created a closed system. The temperature inside the can _decreased (increased/decreased), causing the steam to change from gas state to liquid state. A partial vacuum was created causing the pressure inside the can to be _less (greater/less) than the pressure outside the can. Part 2 1) Obtain a small balloon filled with air. Submerge the balloon in a large beaker of ice water and hold for 3 minutes. Use beaker tongs to keep the balloon submerged. Observe. 2) Transfer balloon to large beaker of hot water and submerge for 3 minutes. Observe. The balloon expanded in hot water. The balloon volume was smallest in cold water. As the water temperature increased, the volume of the balloon increased. This is an example of _Charles s Law.

5 Part 3 1) Obtain a 250-mL Erlenmeyer flask and place milliliters of water inside. 2) Place the flask onto a heating setup (hotplate or wire gauze/ring stand) and heat until a steady stream of steam comes out. DO NOT let the water boil away. 3) Take the flask off of the gauze using flask tongs. 4) While holding onto the neck of the flask using flask tongs, have a lab partner stretch the mouth of a large balloon over the mouth of the flask. Make sure the balloon is centered on the opening of the flask. This creates a closed system. 5) Wait 2-3 minutes and observe. Then place the flask into a beaker of ice water. The balloon collapsed and then inverted into the flask lining the inside of the flask. Placing the balloon over the mouth of the flask created a closed system. As the _temperature in the flask dropped the steam turned to water. Since water in the liquid state takes up less volume than water in the gas state, a partial vacuum was created. The greater _pressure outside of the flask pushed the balloon inside. Part 4 1) Obtain a 1000 ml beaker / candle set-up. 2) Fill the beaker with water until the water level is halfway up the candle. Light the candle. 3) Carefully invert a 1000 ml Erlenmeyer flask over the candle. Observe both candle and the water level. The candle went out and the water level increased and went above the candle. Propose an explanation: Answers will vary from running out of oxygen to pressure greater outside of flask. Conclusion: 1) Give the name of the law that relates pressure to volume. Boyles 2) Give the name of the law that relates volume to temperature. _Charles s 3) The condensing of steam in a closed system creates a partial vacuum. 4) If the volume of a gas is cut by 1/2, the pressure will increase (increase/decrease) by a factor of 2 (2, 1/2) times. 5) If the temperature of a gas is doubled, the volume of the gas will increase (increase/decrease) by a factor of 2 (2, 1/2) times. 6) If the temperature of a gas is tripled, the pressure of the gas will increase (increase/decrease) by a factor of 3 (3, 1/3) times. 7) Graphing pressure vs. volume would produce a curve. 8) Graphing volume vs. temperature would produce a _straight line.

6 Introduction to Gas Laws Lab Quiz NAME: DATE: PERIOD: True (A) or False (B) Place either an A or a B in the blank provided. 1) Boyle s Law states that pressure is inversely proportional to volume. 2) Charles s Law states that volume and temperature are directly proportional. 3) Gay-Lussac s Law states that pressure and temperature are directly proportional. 4) If the pressure is increased by a factor of 3 times then the volume will increase by a factor of 3 times. 5) If the temperature is increased by a factor of 2 times then the pressure will increase by a factor of 2 times. 6) Decreasing the volume of a container by ½ will double the pressure. 7) A graph of volume vs. temperature will produce a curve. 8) A graph of an inversely proportional relationship will produce a straight line. 9) When steam condenses in a closed container a partial vacuum is created. 10) The can was crushed by atmospheric pressure. 11) A balloon placed into cold will increase in volume.

7 Introduction to Gas Laws Lab Make-up NAME: DATE: PERIOD: Background: In a gas, particles are spread far apart; therefore a gas takes up more volume than a solid or a liquid. For example, water in the form of steam takes up about 2000 times the volume that the same amount of water does in liquid form. There are many formulas to describe the behavior of a gas under certain conditions. Boyle s Law, PV=k, states that the pressure is inversely proportional to the volume. Charles s Law, V/T =k, states that volume is directly proportional to the temperature. Gay-Lussac s Law, P/T =k, states that pressure is directly proportional to the temperature. Relationships that are directly proportional produce a straight line graph, while inversely proportional relationships produce a curve. Applying these laws to compare gases under two different sets of conditions gives the formulas: P 1 V 1 =P 2 V 2, V 1 /T 1 =V 2 /T 2, P 1 /T 1 =P 2 /T 2. These three laws together give the Combined Gas Law: P 1 V 1 /T 1 =P 2 V 2 /T 2. Procedure & Observations: Part 1 1) Obtain a large beaker ( ml) and fill 3/4 full of tap water. 2) Obtain an aluminum can and add 7-10 milliliters of water. 3) Place the can on a heating set up (hotplate or wire gauze/ring stand) and heat until a steady stream of steam flows out of the can. 4) Using beaker tongs, grab the aluminum can near the bottom of the can and quickly turn it upside down into the beaker of water. The can was crushed when it was inverted into the beaker of water. When the can was heated, the water turned to, which takes up (more/less) volume than liquid water. When the can was inverted into the water this created a closed system. The temperature inside the can (increased/decreased), causing the steam to change from gas state to state. A partial vacuum was created causing the pressure inside the can to be (greater/less) than the pressure outside the can. Part 2 1) Obtain a small balloon filled with air. Submerge the balloon in a large beaker of ice water and hold for 3 minutes. Use beaker tongs to keep the balloon submerged. Observe. 2) Transfer balloon to large beaker of hot water and submerge for 3 minutes. Observe. The volume decreased in the ice water and increased in the hot water. As the water temperature increased, the volume of the balloon. This is an example of Law.

8 Part 3 1) Obtain a 250-mL Erlenmeyer flask and place milliliters of water inside. 2) Place the flask onto a heating setup (hotplate or wire gauze/ring stand) and heat until a steady stream of steam comes out. DO NOT let the water boil away. 3) Take the flask off of the gauze using flask tongs. 4) While holding onto the neck of the flask using flask tongs, have a lab partner stretch the mouth of a large balloon over the mouth of the flask. Make sure the balloon is centered on the opening of the flask. This creates a closed system. 5) Wait 2-3 minutes and observe. Then place the flask into a beaker of ice water. The balloon was pushed into the flask and lined the inside of the flask. Placing the balloon over the mouth of the flask created a system. As the in the flask dropped the steam turned to water. Since water in the liquid state takes up less than water in the gas state, a partial vacuum was created. The greater outside of the flask pushed the balloon inside. Part 4 1) Obtain a 1000 ml beaker / candle set-up. 2) Fill the beaker with water until the water level is halfway up the candle. Light the candle. 3) Carefully invert a 1000 ml Erlenmeyer flask over the candle. Observe both candle and the water level. The flame went out and then the water level inside the flask increased and went above the candle. Propose an explanation: Conclusion: 1) Give the name of the law that relates pressure to volume. 2) Give the name of the law that relates volume to temperature. 3) The condensing of steam in a closed system creates a partial. 4) If the volume of a gas is cut by 1/2, the pressure will (increase/decrease) by a factor of (2, 1/2) times. 5) If the temperature of a gas is doubled, the volume of the gas will (increase/decrease) by a factor of (2, 1/2) times. 6) If the temperature of a gas is tripled, the pressure of the gas will (increase/decrease) by a factor of (3, 1/3) times. 7) Graphing pressure vs. volume would produce a. 8) Graphing volume vs. temperature would produce a line.