Downloaded 271 times
Uploaded byeLearningJa
Physics M3 Gas Laws
The document provides an introduction to gas laws including Boyle's law, Charles' law, the pressure law, and the combined gas law. It includes objectives, demonstrations, examples, graphs, and a quiz. The key points covered are: - Boyle's law states that the pressure and volume of a gas are inversely proportional at constant temperature. - Charles' law states that the volume of a gas is directly proportional to its temperature when pressure remains constant. - The pressure law states that the pressure of a gas is directly proportional to its temperature at constant volume. - The combined gas law relates the pressure, volume, and temperature of a gas, stating their product over temperature is a constant.
More Related Content
Physics M3 Gas Laws
- 1. GAS LAWS PHYSICS MODULE 3 UNIT 1 LESSON 6-8 BEGIN
- 2. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Introduction Part1 - Boyle’s Law Demonstration: Teachers may introduce this lesson by having students attempting to compress the sides of empty 600ml plastic water bottles with a tightly fitting cap. He/She will ask the students to describe what they feel. If the students do not realize that the gases (air) inside the bottle push back, they will be prompted to use the word "pressure" to describe the pushing back that they feel on bottle. Possible Answers: 1.No. 2.The volume decreases. 3.Yes, temperature. Questions: 1. Is there a change in the number of particles or in the mass of the particles? 2. What happens to the volume of gas in the empty bottles as you compress the sides of the empty 600ml plastic water bottle? 3. Is there any other variable which could cause the empty 600ml plastic water bottle and its contents to change? CHECK
- 3. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Introduction Part2- Charles’ Law Teacher Demonstration The teacher will show the students two inflated balloons of similar size and then, he or she will place one in warm water and the other in ice. After a minute the teacher will remove both balloons and then he or she will pass them around the class. Questions: 1.What happens to the volume of the balloon when it is warmed? 2.What happens to the volume of the balloon when it is cooled? 3.What variable was changed? Expected Answers: 1.It expanded (increased). 2.It shrunk (decreased). 3.The volume and temperature of air (gas) in the balloon.CHECK
- 4. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Introduction Part2- Charles’ Law Questions cont’d 4.A boy bought helium balloons for his friend’s birthday in a warm store in Santa Cruz. He noticed that the balloons shrunk and they weren’t floating as high when he took them to a very cold air conditioned room. Why was this happening? 5.What is the relationship between gas volume and temperature? Expected Answers: 4.The temperature of the room caused the temperature in the balloons to decrease. This causes a decrease in the volume of the balloons, hence a decrease in the upthrust. 5.As the temperature increases, the volume of gas will increase.CHECK
- 5. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Introduction Part3 - Pressure and General Laws Teacher Demonstration: The teacher places a glass bottle of diameter approximately 4 cm in front of the students. Then he or she will put four lit match sticks inside the bottle. This will be followed by the teacher placing a peeled hardboiled egg over the mouth of the bottle. Question 1: What happens to the egg when the match sticks went out? Give reasons for your answer? Expected Answer to Question 1 The egg will be sucked into the bottle. This is due to the drop in pressure as the air inside cooled from the match sticks going out (slower colliding air molecules with inside walls of bottle). The air pressure outside remains the same thus pushing the egg into the bottle CHECK
- 6. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Introduction Part3 - Pressure and General Laws Teacher Demonstration: The teacher places a glass bottle of diameter approximately 4 cm in front of the students. Then he or she will put four lit match sticks inside the bottle. This will be followed by the teacher placing a peeled hardboiled egg over the mouth of the bottle. Question 2: How would you get the egg out of the bottle? Expected Answer to Question 2 This can be done by inverting the bottle so that the egg is covering the opening. Then you will run hot water over the bottle. Another way that you could get the egg out of the bottle is by placing your mouth over the opening inverted bottle and blow hard across the mouth of the bottle. CHECK
- 7. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Objectives As aresult of this lesson, the student will be able to: 1.conduct an experiment to verify Boyle’s Law 2.deduce the formula PV= k from an experiment 3.use the formula PV= k in calculations in problems based on Boyle’s Law. 4.conduct an experiments to verify Charles’ gas law 5.deduce the formula from an experiment 6.use the formula in calculations in problems based on Charles’ gas law. 7.discuss how knowledge of combined gas law does what? 8.conduct an experiments to verify the Pressure law 9.recall mathematical expressions describing the Pressure Law and the Combined Gas Law. 10.use the mathematical formula for the pressure and combined gas laws to solve problems
- 8. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 1 -Boyle’s Law Look at the animated clip on the right and then answer the questions. 1.What are the constant variables ? 2.What are changing variables? 3.What is the relationship between the changing variables? Taken from http://crsic.umbb.dz/gaslaws.ppt Answer to Qu. 3: Pressure is inversely proportional to volume. Answer to Qu. 1: Temperature and mass. Answer to Qu. 2: Pressure & Volume CHECK
- 9. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 1 -Boyle’s Law (cont.) What is Boyle’s Law? Boyle’s Law states that for a fixed mass of gas at constant temperature the pressure varies inversely as the volume (pV = k). 2211 VPVP = 1 P V µ This is used in the form: pressure (Pa – Pascal) volume (m3 )
- 10. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 1 -Boyle’s Law (cont.) Graphs of Boyle’s Law: pressure volume volume 1 pressure Application of Boyle’s Law A bicycle pump is a good example of Boyle’s law. As the volume of the air trapped in the pump is reduced, its pressure goes up, and air is forced into the tire.
- 11. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 1 -Boyle’s Law (cont.) Example 1.1 A sample of gas has a volume of 30 cm3 at a pressure of 2x105 Pa. Calculate the new volume of gas when the pressure is increased to 4x105 Pa, assuming the temperature remains constant. Pa102P 5 1 ×= 3 1 cm30V = 5 2P 4 10 Pa= × ?V2 = 2211 VPVP = ( ) ( )5 5 22 10 30 4 10 V× × = × × ( )6 5 26 10 4 10 V× = × × 6 2 5 6 10 V 4 10 × = × 3 2V 15 cm= SHOW ME.
- 12. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 1 -Boyle’s Law - Activity In groups of four, the teacher will ask the students to discuss how Boyle’s law governs the following Phenomena. 1. The use of syringes used in medicine. 2. The use of spray cans in spraying paint and air freshener. 3. Inhalation and exhalation in respiration. 4. The combustion of fuel in the pistons of a vehicle. 5. The blowing of bubbles and causing them to pop. After approximately five minutes in their discussion the students will be asked to halt their group discussion and will be engaged in a brief class discussion.
- 13. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 2 -Charles’ Law 1. What are the constant variables ? 2. What are the changing variables ? 3. What is the relationship between the changing variables? Taken from http://crsic.umbb.dz/gaslaws.ppt Answer to Qu. 1: Pressure and mass. Answers to Qu 2: Temperature & Volume Answer to Qu. 3: Volume is directly proportional to the absolute temperature.CHECK
- 14. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 2 -Charles’ Law (cont.) What is Charles’ Law? Charles’ Law states that the volume of a constant mass of gas is directly proportional to the absolute temperature if the pressure remains constant. 2 2 1 1 T V T V = constant T V =TV∝ This is used in the form: volume (m3 ) temperature (K) When using this equation you must use temperature as kelvin (K).
- 15. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 2 -Charles’ Law (cont.) Graphs of Charles’ Law o V T / C -273 When the graph is extended back ( the dotted line) until the volume reaches zero, it crosses the axis at -273°C. If the graph is volume against temperature in kelvin, the graph will show volume to be directly proportional to temperature as shown below. V T / K 0 NOT directly proportional directly proportional
- 16. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 2 -Charles’ Law (cont.) Example 2.1 60 cm3 of a gas is at 27 °C. Calculate the volume of this gas at 10 °C, if the pressure is unchanged. 3 1V 60 cm= C27T1 °= ?V2 = 2 2 1 1 T V T V = 27327 += K300= C10T2 °= 27310 += K283= 260 V 300 283 = 2300 V 283 60× = × 2 16,980 V 300 = 3 2V 56.6 cm= What would the volume be if you did not convert to Kelvin? 22.2cm3 WRONG SHOW ME.
- 17. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 3 -Pressure Law (cont.) Click the picture below. http://aspire.cosmic-ray.org/javalabs/java12/gaslaws/act2/tchrpage.htm#lab
- 18. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 3 -Pressure Law (cont.) What is Pressure Law? Pressure Law states that the pressure of a constant mass of gas is directly proportional to the absolute temperature if the volume remains constant. 2 2 1 1 T P T P = constant T P =TP ∝ This is used in the form: pressure (Pa – Pascal) temperature (K) When using this equation you must use temperature as kelvin (K).
- 19. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 3 -Pressure Law (cont.) Graphs of Pressure Law The straight line graph does not pass through the origin. p T / oC -273 If the graph is extended back until the pressure reaches zero, it will cross the axis at -273°C. This is known as absolute zero. If the pressure against temperature in kelvin graph is drawn, the graph will show pressure being directly proportional to temperature. p T / K0 NOT directly proportional directly proportional
- 20. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 3 -Pressure Law (cont.) Example 3.1 A quantity of gas has a pressure of 2.5x104 Pa at a temperature of 20 °C. Calculate the new pressure when the temperature reaches 37 °C assuming the volume remains constant. To see solution, click 4 1P 2.5 10 Pa= × C20T1 °= ?P2 = 2 2 1 1 T P T P = 27320 += K293= C37T2 °= 27337 += K310= 4 22.5 10 P 293 310 × = ( )4 2293 P 310 2.5 10× = × × 5 2 77.5 10 P 293 × = 4 2P 2.65 10 Pa= × SHOW ME.
- 21. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 4 -Combined Gas Law What is the Combined Gas Law? Combined Gas Law states that the ratio of the product of pressure and volume to the absolute temperature, is a constant. constant T VP = × 2 22 1 11 T VP T VP =pressure (Pa) When using this equation you must use temperature as kelvin (K). This equation is used in the form: temperature (K) volume (m3 )
- 22. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 4 -Combined Gas Law (cont.) When applying either of the three gas laws to the general gas equation, you do so by removing the constant variable from the equation. = P1 V1 T1 P2 V2 T2 Boyle’s Law Charles’ Law Pressure Law
- 23. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X 4 -Combined Gas Law (cont.) Example 4.1 A sample of nitrogen gas has a volume of 0.180 L, at a pressure of 0.800 atm and a temperature of 29°C. What is the new temperature(°C) of the gas at a volume of 90.0 mL and a pressure of 3.20 atm? Solution P1 = 0.800 atm V1 = 180 mL T1 = 302 K P2 = 3.20 atm V2= 90 mL T2 = ?? 2 22 1 11 T VP T VP = 2 0.8atm 180 3.2atm 90 302K T ml ml× × = 2 288 0.477 T = 2 288 T 603.8 604 0.477 = = ≈ 0 2T 604 273 331 C= − =
- 24. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X QUIZ 1. Areyou ready to test yourself? 2. There are seven multiple choice items that you are required to do. 3. For each item, click on the letter of the correct response and then click the button ‘NEXT QUESTION’ to continue. 4. Click the next button to begin. 24
- 25. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X QUIZ: Question1 The formula represents 25 A. Boyle’s Law B. Combined Gas Law C. Pressure Law D. Charles’ Law FEEDBACKFEEDBACK 1 2 1 2 V V T T =
- 26. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Quiz: Feedbackto Question 1 The formula represents 26NEXT QUESTIONNEXT QUESTION Charles’ Law states that the volume of a constant mass of gas is directly proportional to the absolute temperature if the pressure remains constant. The law can be represented by 1 2 1 2 V V T T = 1 2 1 2 V V T T =
- 27. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X QUIZ: Question2 What is absolute temperature? 27 A. 100K D. 273K C. 0°C B. -273°C FEEDBACKFEEDBACK
- 28. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Quiz: Feedbackto Question 2 What is absolute temperature? 28NEXT QUESTIONNEXT QUESTION Absolute temperature is temperature measured in Kelvin.
- 29. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X QUIZ: Question3 If there are 5.6 liters of gas in a piston at a pressure of 1.7 atm is compressed until its volume is 4.9 L, what will the new pressure inside the piston be? 29 A. 1.7 atm D. 2.7atm B. 1.46atm C. 1.94atm FEEDBACKFEEDBACK
- 30. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Quiz: Feedbackto Question 3 If there are 5.6 liters of gas in a piston at a pressure of 1.7 atm is compressed until its volume is 4.9 L, what will the new pressure inside the piston be? 30NEXT QUESTIONNEXT QUESTION 1 1 2 2 2 2 P V = P V (1.7 atm)(5.6 L) = P (4.9 L) 9.52atm(L) P = =1.94 atm 4.9L
- 31. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Quiz: Question4 Calcium Carbonate usually decomposes at 1200 0 C to form carbon dioxide and calcium oxide. 45 liters of carbon dioxide are collected at 1200 0 C. If it is allowed to cool, what will be the volume of this gas at 25 0 C, assuming the pressure remains constant? 31 A. 2160ml D. 67ml C. 0.93ml B. 9.1ml FEEDBACKFEEDBACK
- 32. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Quiz: Feedbackto Question 4 Calcium Carbonate usually decomposes at 1200 0 C to form carbon dioxide and calcium oxide. 45 liters of carbon dioxide are collected at 1200 0 C. If it is allowed to cool, what will be the volume of this gas at 25 0 C, assuming the pressure remains constant? 32NEXT QUESTIONNEXT QUESTION 1 2 1 2 2 2 V 45 1473 298 13410 9.1 1473 V T T L V K K LK V L K = = = =
- 33. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X QUIZ: Question5 A gas has a volume of 230 mL at 75o C and 170 kPa. What will be its volume at a temperature of 20o C and a pressure of 1.0 × 105 kPa? 33 B. 8.9L D. 8.9ml C.4.64ml A. 4.64L FEEDBACKFEEDBACK
- 34. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X Quiz: Feedbackto Question 5 A gas has a volume of 230 mL at 75o C and 170 kPa. What will be its volume at a temperature of 20o C and a pressure of 1.0 × 105 kPa? 34 1 1 2 2 1 2 1 1 2 2 8 2 2 (170000)(0.23 )(348 ) 4.64 (1.0 10 )(293 ) PV PV T T PV T L K V L P T K = = = = × NEXT QUESTIONNEXT QUESTION
- 35. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X QUIZ: Question6 In your notebook, do the following questions. Click CHECK for answers. a.A balloon contains 30.0 L of He gas at 103kPa. What is the volume of He when the balloon rises to an altitude where the pressure is only 25.0kPa, assuming the temperature remains constant? b.A balloon inflated in a room at 24.0˚C has a volume of 4.00 L. The balloon is heated to a temperature of 58.0˚C. What is the new volume, assuming the pressure remains constant? c.A sample of N2(g) is at STP. What will the pressure (in atm) be if the temp is increased to 373K at constant volume? d.The volume of a gas-filled balloon is 30.0L at 98.0˚C and 1147 mmHg. What would the volume be at STP? END OF QUIZEND OF QUIZ Answers: a) 156 L b) 4.46 L c) 1.37 atm d) 33.3 LCHECK
- 36. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X End ofQuiz You have reached the end of the quiz. If you wish to review this lesson, go to the first slide. If you have finished viewing the lesson, click the Close (X) button. 36
- 37. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X References Charles LawPowerPoint - Temperature & Volume Relationship. Retrieved from http://www.chalkbored.com/lessons/chemistry-11/charles-law.ppt on Friday, July27,2012. Gases Retrieved from http://www.chemistrygeek.com/chemistrypowerpoint/Student%20Ch %2013%20Gases.ppt on Friday ,July27,2012. Gas Laws Retrieved from http://www.google.com.jm/url?sa=t&rct=j&q=real %20life%20application%20of%20combined%20gas%20law%20in %20doc.&source=web&cd=20&ved=0CGoQFjAJOAo&url=http://staffweb.psdscho ols.org/rjensen/powerpoints/gas_laws_pp_lauren1.ppt&ei=eCIbUP3SDuXk0QGSIC QCg&usg=AFQjCNEoohP4BrJbAQwPReV6EpNnbLxSwg&sig2=338kld6X3LP5vS6rJJZ nyA on Friday, July27, 2012.
- 38. OBJECTIVES BOYLE’S LAW CHARLES’ LAW PRESSURE LAW COMBINED GAS LAW QUIZINTRODUCTION X References (cont.) Gases.Retrieved from http://www.chemistrygeek.com/chemistrypowerpoint/Student%20Ch %2013%20Gases.ppt on on Friday ,July27,2012.