Presentation is loading. Please wait.

Presentation is loading. Please wait.

Agenda: 4/22 Gases & Gas Laws Purpose: To use mathematical formulas to predict how a gas will change Warm-up: Stoichiometry Problems with Gases States.

Similar presentations


Presentation on theme: "Agenda: 4/22 Gases & Gas Laws Purpose: To use mathematical formulas to predict how a gas will change Warm-up: Stoichiometry Problems with Gases States."— Presentation transcript:

1

2 Agenda: 4/22 Gases & Gas Laws Purpose: To use mathematical formulas to predict how a gas will change Warm-up: Stoichiometry Problems with Gases States of Matter Kinetic Molecular Theory Measurements used in Gas

3 3 Essential to Stoichiometry Set-up of problems Given: Amount & Unit Do I need to convert the given to moles? Mole RatioDo I need to convert from moles to another unit? Unknown: Unit The mole ratio is the heart of the stoichiometry calculation

4 Stoichiometry Calculations 4 Mole Ratio Mole________ Mole X Mass Volume of a Gas Particles Volume of a Gas Mass Particles

5 Stoichiometry Problem To produce ammonia, nitrogen gas reacts with hydrogen gas. Write the balanced chemical equation: Calculate: How many liters of ammonia will be produced if there are 10 moles of nitrogen gas (and plenty of hydrogen gas for the reaction to proceed)? How many liters of hydrogen gas will be needed to react with 25 liters of nitrogen gas?

6 GASES Unit 8 Essential Standards: 2.1.5 Chapters 13 & 14 Purpose: To use mathematical formulas to predict how a gas will change

7 GAS LAWS (FORMULAS) - Gas molecules act in orderly and predictable ways. - We can use mathematical formulas to predict what they will do when we change Temperature, Pressure, or Amount.

8 Review: What are gases? Describe the location & movement of the particles at each state of matter? How are gases different?

9 What are gases? How are they different? Describe the gases in terms of size and type of compound (bond type).

10 Elements that exist as gases at 25 0 C and 1 atmosphere

11 Differentiating gases from solids and liquids Kinetic Molecular Theory or “Why solids, liquids and gases behave as they do” How are gases different?

12 Differentiating gases from solids and liquids Kinetic Molecular Theory or “Why solids, liquids and gases behave as they do” All matter is made of __________________ and these are always in _________________. - Temperature determines the ____________ of the ___________________. There are 3 states of matter on earth: _______, ________________, __________________.

13 Gas Behavior – Kinetic Molecular Theory http://ed.ted.com/lessons/describing-the-invisible- properties-of-gas-brian-bennett http://ed.ted.com/lessons/describing-the-invisible- properties-of-gas-brian-bennett 5 characteristics of gases 1. - 2. - 3. - 4. - 5. - http://education-portal.com/academy/lesson/the-kinetic- molecular-theory-properties-of-gases.html#lesson

14 Chemical particles (atoms, molecules, or compounds) act differently when they are in different states of matter PHET – States of Matter – Basics https://phet.colorado.edu/en/simulation/states-of- matter-basics Animation – http://www.pbs.org/wgbh/nova/physics/states-of-matter.html Includes Temperature & Pressure; Water, Carbon dioxide and hydrogen gas https://phet.colorado.edu/en/simulation/states-of- matter-basics http://www.pbs.org/wgbh/nova/physics/states-of-matter.html animations Heating curve KMT- Solid KMT-Liquid KMT- Gas

15 Ways we measure gases: AbbreviationMeasurement Volume Temperature Number or quantity – atoms or molecules Pressure

16 Gas Temperature: Always use Kelvin Celcius Kelvin

17 Temperature Conversions Convert 25.0 ℃ to Kelvin Convert 375K to ℃ Convert -50℃ to K

18 Pressure http://www.dlt.ncssm.edu/Tiger/chem3.htm http://education-portal.com/academy/lesson/pressure- and-temperature-conversions.html#lesson http://education-portal.com/academy/lesson/pressure- and-temperature-conversions.html#lesson Animation Atmospheric pressure You Tube – Atmospheric Pressure http://www.youtube.com/watch?v=xJHJsA 7bYGc

19 Sea level1 atm 4 miles0.5 atm 10 miles 0.2 atm Air Pressure of the Atmosphere

20 Units of Pressure 1 atm = 760 mmHg = 760 torr 1 atm = 101 kPa (101,325 Pa) Barometer Pressure = Force Area Or 760 mm of Mercury

21 Measuring Pressure: Units UnitUnit nameSTP: Measurement at sea level & 0°C Mm HgMm Mercury760 mm Hg Atmatomospheres1 atm kPakiloPascals101 kPa Torr 760 torr PSI* Tire pressure Pounds per square inch 14.7 psi

22 STP = Standard Temperature & Pressure What does the chemistry reference table tell you? STP= 1 atm at 0°C or _________ K = __________mm Hg = __________ KPa = __________ torr Standard Molar Volume of a Gas: 1 mole = ______ Liter (volume occupied by one mole of any gas at STP = ______ Liter)

23 Pressure Conversions Convert 98.35 kPa to atm Convert 745 mm Hg to atm Convert 740 mm Hg to kPa

24 GAS LAWS Shows the relationship of volume. Temperature, pressure and quantity of molecules in mathematical terms Gases act in predictable ways so we can use mathematical formulas to determine how they act

25 http://phet.colorado.edu/en/simulation/gas-properties

26 Three Major Laws Combined Gas Law P ₁V₁= P₂V₂ T₁ T₂ Ideal Gas Law PV = nRT Dalton’s Law of Partial Pressure P total = P ₁+P₂+P₃+P etc.

27 “A Rational Equation” means an equation which uses ________.

28

29

30

31

32

33

34

35 Isolating the Unknown Variable P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ We can slide diagonally across the equal sign without changing the mathematical relationship. Need variable cards

36 Isolating the Unknown Variable P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ We can slide diagonally across the equal sign without changing the mathematical relationship.

37 Isolating the Unknown Variable P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ We can slide diagonally across the equal sign without changing the mathematical relationship.

38 Isolating the Unknown Variable P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ We can slide diagonally across the equal sign without changing the mathematical relationship.

39 Combined Gas Law

40 Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

41 Combined Gas Law : Example Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ A gas at 110 kPa and 30 ℃ fills a flexible container with an initial volume Of 2.00L. If the temperature is raised to 80℃ and the pressure increased To 440 kPa, what is the new volume? Answer: 0.58L

42 Constant variableChanging variablesLaw TemperatureBoyles PressureCharles VolumeGay-Lussac Combined Gas Law P ₁V₁= P₂V₂ T₁ T₂ Keeping one variable constant :

43 Boyles’ Law Animation http://group.chem.iastate.edu/Greenbowe/sections/project folder/flashfiles/gaslaw/boyles_law_graph.html http://group.chem.iastate.edu/Greenbowe/sections/project folder/flashfiles/gaslaw/boyles_law_graph.html

44 Boyles’ Law: Vary P & V Uses: bicycle pump; syringe for injections; popping a balloon by squeezing; Scuba diving: increase in bubble size as rise to surface of water Others? Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

45 Boyles’ Law: Example A cylinder of oxygen has a volume of 2.0L. The pressure of the gas is 10 atm at 0 ℃. What will be the volume at STP? Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

46 Boyles’ Law: Practice Problems Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

47 Boyles’ Law: Practice Problems Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

48 Charles’ Law – animation http://group.chem.iastate.edu/Greenbowe/sections/project folder/flashfiles/gaslaw/charles_law.html http://group.chem.iastate.edu/Greenbowe/sections/project folder/flashfiles/gaslaw/charles_law.html

49 http://phet.colorado.edu/en/simulation/gas-properties

50 Charles’ Law: Vary V & T Uses: Hot Air Balloons Decorating with party balloons; Cooked turkey monitor/device; Playing basketball on a cold day Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

51 Charles’ Law: Practice Problems Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

52 Charles’ Law: Practice Problems Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

53 Gay Lussac’s Law: Vary P and T Uses: Heating cans (soup, spray); Pop corn; Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

54 http://phet.colorado.edu/en/simulation/gas-properties

55 Gay Lussac’s Law: Practice Problems Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

56 Gay Lussac’s Law: Practice Problems Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂

57 COMBINED GAS LAW

58 Combined Gas Law Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ A balloon is partially filled with helium on the ground in the mountains (temp. is 22°C and the pressure is 740 torr. At these conditions, the volume is 10 m³. If released, what would be the volume in m³ at an altitude 5300 m where the pressure is 370 torr and the temperature is - 23°C?

59 Combined Gas Law Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ The volume of a gas is 27.5 mL at 22°C and 0.974 atm. What will the volume be at 15°C and 0.993 atm?

60 Combined Gas Law Initial condition(1)Final condition (2) Pressure Volume Temp. K P ₁ V ₁ = P ₂ V ₂ T ₁ T ₂ A 700 mL gas sample at STP is compressed to a volume of 200mL and the temperature is increased to 30°C. What is the new pressure of the gas?

61 P₁ V₁V₁ T₁T₁ P₂P₂ V₂V₂ T₂T₂ 1.5 atm3.0L20°C2.5 atm?30°C Combined Gas Law

62 Ideal Gas Law Use when________ is included. Formula: PV = nRT P = V= n= R= 0.0821 L∙atm mol∙K T=

63 Ideal Gas Law Formula: PV = nRT What is the pressure exerted by a 0.5 mol sample of N ₂ gas in a 10L container at 278K? P = V= n= R= 0.0821 L∙atm mol∙K T=

64 Ideal Gas Law Formula: PV = nRT How many moles of O ₂ will occupy a volume of 2.5L at 1.2 atm and 25 °C? P = V= n= R= 0.0821 L∙atm mol∙K T=

65 Ideal Gas Law: PV = nRT What volume will 2 mol of N ₂ gas occupy at 720 torr and 20°C? P = V= n= R= 0.0821 L∙atm mol∙K T=

66 Ideal Gas Law: PV = nRT At what temperature will 5 grams of Cl ₂ gas exert with a pressure of 900 mm Hg and volume of 750 mL? P = V= n= R= 0.0821 L∙atm mol∙K T=

67 Dalton’s Law of Partial Pressure Mixture of gases (no reaction takes place) What is the total blood gas pressure for a person having CO ₂ partial pressure of 60.1 mm Hg and an O₂ partial pressure of 39.2 mm Hg? P total = P ₁ +P ₂ +P ₃ +P etc.

68 Dalton’s Law of Partial Pressures V and T are constant P1P1 P2P2 P total = P 1 + P 2

69 Avogadro’s Law V  number of moles (n) V = constant x n V 1 /n 1 = V 2 /n 2 Constant temperature Constant pressure

70 Animation – http://www.pbs.org/wgbh/nova/physics/states-of- matter.html http://www.pbs.org/wgbh/nova/physics/states-of- matter.html Includes Temperature & Pressure; Water, Carbon dioxide and hydrogen gas DiscoveryEd video: Kinetic Molecular Theory Kinetic_Molecular_Theory.wmv

71 http://education-portal.com/academy/course/general- chemistry-course.html


Download ppt "Agenda: 4/22 Gases & Gas Laws Purpose: To use mathematical formulas to predict how a gas will change Warm-up: Stoichiometry Problems with Gases States."

Similar presentations


Ads by Google