Agenda: 4/23 or 4/24 Purpose: To use mathematical formulas to predict how a gas will change Warm-up: States of Matter Kinetic Molecular Theory Measurements used in Gas

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

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.

Warm-up: What are gases? Describe the location & movement of the particles at each state of matter? How are gases different?

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

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

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

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: _______, ________________, __________________.

DiscoveryEd video: Kinetic Molecular Theory Kinetic_Molecular_Theory.wmv Animation – matter.html matter.html Includes Temperature & Pressure; Water, Carbon dioxide and hydrogen gas

Gas Behavior – Kinetic Molecular Theory properties-of-gas-brian-bennett properties-of-gas-brian-bennett 5 characteristics of gases

Chemical particles (atoms, molecules, or compounds) act differently when they are in different states of matter PHET – States of Matter – Basics matter-basics animations Heating curve KMT- Solid KMT-Liquid KMT- Gas

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

Gas Temperature: Always use Kelvin Celcius Kelvin

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

Pressure Animation Atmospheric pressure You Tube – Atmospheric Pressure

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

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

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

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)

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

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

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.

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

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

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.

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.

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.

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

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

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

Boyles’ Law Animation rojectfolder/flashfiles/gaslaw/boyles_law_graph.html

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

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

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

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

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

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

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

Gay Lusaac’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

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

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

COMBINED GAS LAW

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?

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 atm. What will the volume be at 15°C and atm?

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?

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

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

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= L∙atm mol∙K T=

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= L∙atm mol∙K T=

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= L∙atm mol∙K T=

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= L∙atm mol∙K T=

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.

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

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