DO NOW List 5 gases that you can think of without the aide of a book. Classify these gases are either elements, compounds or mixtures. Explain your classifications.

ESSENTIAL QUESTION What property of a gas allows it to exert pressure, how is that pressure measured, and what units are used to measure that pressure?

VOCABULARY PressureAtmospheric Pressure ForceBarometer Evangelista TorricelliPascal Kilopascal

STANDARD TEMPERATURE AND PRESSURE In order to compare volumes of gas, one must know the temperature and pressure at which the volumes are measured. STP (standard temperature and pressure) = 1 atm and 0 0 C.

ATMOSPHERE OF PRESSURE CONVERSION CHART 1 atm = 760mmHg = 760 torr 1 atm = 1.013x10 5 Pa = 101.3kPa = 1.013bar 1 atm = 29.92in Hg = psi

PRACTICE The average atmospheric pressure in Denver, Colorado, is atm. Express this pressure in a) millimeters of mercury (mmHg) b) Kilopascals (kPa). a) mmHg b)84.08 kPa

PRACTICE Convert a pressure of 1.75 atm to kPa and to mmHg 1.75 atm kPa = kPa 1 atm 1.75 atm 760mmHg = 1330 mmHg 1 atm

MORE PRACTICE The critical pressure of carbon dioxide is 72.7 atm. What is this value in units of pascals? 72.7 atm kPa = kPa 1 atm = Pa = 7.36 X10 6 Pa

STOP AND THINK Standard temperature and pressure of a gas is _________________, and ________________.

DO NOW What do you think is the relationship that exist between the pressure of a gas and the volume of a gas? Explain your answer.

ESSENTIAL QUESTION How can you use the relationship that exist between the pressure and the volume of a gas to determine unknown values of pressure and volume?

GAS LAWS Gas laws show the different relationships that exist between the different properties of a gas

BOYLES LAW Boyles Law shows us the relationship between pressure and volume Boyles discovered that the volume and pressure of a gas are inversely related ( when one increases, the other one decreases)

BOYLES LAW Boyles Law states that the volume of a fixed mass of gas varies inversely with the pressure at constant temperature. What is constant temperature? Boyles law formula – P 1 V 1 = P 2 V 2

PRACTICE A sample of oxygen gas has a volume of 150.0mL when its pressure is atm. What will the volume of the gas be at a pressure of atm if the temperature remains constant?

PRACTICE The piston of an internal combustion engine compresses 450 mL of gas. The final pressure is 15 times greater than the initial pressure. What is the final volume of gas, assuming constant temperature?

PRACTICE A helium filled balloon contains 125mL of gas at a pressure of atm. What volume will the gas occupy at standard pressure?

MORE PRACTICE A balloon filled with helium gas has a volume of 500mL at a pressure of 1 atm. The balloon is released and reaches an altitude of 6.5km, where the pressure is 0.5 atm. If the temperature has remained the same, what volume does the gas occupy at this height?

STOP AND THINK According to Boyle’s Law, the volume and pressure of a gas have an _________________ relationship.

DO NOW Think of the way gas molecules behave and answer the question below. What should the relationship be between the volume of a gas and the temperature of a gas?

ESSENTIAL QUESTION How can you use the kinetic molecular theory to explain the relationship between the volume and the temperature of a gas?

REVIEW Boyle’s Law 1.What properties of gases are represented by Boyle’s law 2.What is the relationship that exist between the pressure and the volume of a gas according to Boyle’s Law? 3.How is a gas able to exert pressure on it’s container?

CHARLES LAW Experiments done by Charles showed that all gases expand to the same extent when heated through the same temperature interval. Found that the volume of the gas changed by 1/273 for each celsius degree( 0 C).

KELVIN/ ABSOLUTE ZERO -273 is referred to as absolute zero K= C

CHARLES LAW Gas volume and Kelvin temperature are directly proportional to each other at constant pressure. Charles Law states that the volume of a fixed mass of gas at a constant pressure varies directly with the Kelvin temperature. V 1 = V 2 T 1 T 2

PRACTICE A sample of neon gas occupies a volume of 752 mL at 25 0 C. What volume will the gas occupy at 50 0 C if the pressure remains constant? Ans: 815mL

PRACTICE A sample of neon gas has a volume of 752 mL at 25 0 C. What will the volume at C be if pressure is constant? 941 mL

PRACTICE A sample of nitrogen gas is contained in a piston with a freely moving cylinder. At 0 0 C, the volume of the gas is 375 mL. To what temperature (in celsius) must the gas be heated to occupy a volume of 500 mL? 91 0 C

STOP AND THINK How does Boyle’s Law differ from Charles Law?

DO NOW Think of the way gas molecules behave and answer the question below. What should the relationship be between the pressure of a gas and the temperature of a gas?

ESSENTIAL QUESTION How does kinetic energy affect the energy and frequency of collisions of the gas molecules?

GAY- LUSSAC’S LAW The energy and frequency of collisions depends on kinetic energy. High kinetic energy equals high movement of molecules High movement of molecules equals a high frequency of collisions High frequency of collisions equals high pressure

GAY-LUSSAC’S LAW Gay-Lussac’s law states that the pressure of a fixed mass of gas at constant volume varies directly with the Kelvin temperature. The affect of kinetic energy on the gas molecules tells us that the relationship is a direct relationship (when one value goes up, the other value goes up as well). P 1 = P 2 T 1 T 2

PRACTICE The gas in a container is at a pressure of 3.00 atm at 25 0 C. Directions on the container warn the user not to keep it in a place where the temperature exceeds 52 0 C. What would the gas pressure in the container be at 52 0 C ? 3.27 atm

PRACTICE A gas cylinder at room temperature ( C) is thrown into an incinerator where the temperature reaches C. If the gas inside the container was initially at a pressure of 1.0 atm, what pressure did it reach inside the incinerator? Assume the gas was at constant volume and the container did not explode. 2.6 atm

PRACTICE A sample of helium gas has a pressure of 1.20 atm at 22 0 C. At what Celsius temperature will the helium reach a pressure of 2.00 atm, assuming constant volume? C

DO NOW If a sample of gas undergoes a change in temperature, volume, and pressure all at the same time, what formula would you use to address the difference between theses three variables?

COMBINED GAS LAW Three variables are present Changes are happening all at the same time Conditions don’t allow for one variable to be constant Boyles, Charles’, and Gay-Lussac’s laws are represented

COMBINED GAS LAW The combined gas law expresses the relationship between pressure, volume, and temperature of a fixed amount of gas.

PRACTICE A helium filled balloon has a volume of 50.0 L at 25 0 C and 1.08 atm. What volume will it have at atm and C ? 60.0 L He

PRACTICE The volume of a gas is 27.5 mL at C and atm. What will the volume be at C and atm? 26.3 mL

PRACTICE A mL gas sample at STP is compressed to a volume of mL, and the temperature is increased to C. What is the new pressure of the gas in Pa? 3.94 x 10 5 Pa

DO NOW If a sample of gas undergoes a change in temperature, volume, and pressure all at the same time, what formula would you use to address the difference between theses three variables?

THE COMBINED GAS LAW Three variables are present Changes are happening all at the same time Conditions don’t allow for one variable to be constant Boyles, Charles’, and Gay-Lussac’s laws are represented

THE COMBINED GAS LAW The combined gas law expresses the relationship between pressure, volume, and temperature of a fixed amount of gas.

PRACTICE A helium filled balloon has a volume of 50.0 L at 25 0 C and 1.08 atm. What volume will it have at atm and C ? 60.0 L He

PRACTICE The volume of a gas is 27.5 mL at C and atm. What will the volume be at C and atm? 26.3 mL

….AND MORE PRACTICE A mL gas sample at STP is compressed to a volume of mL, and the temperature is increased to C. What is the new pressure of the gas in Pa? 3.94 x 10 5 Pa

DO NOW Write out and balance the flowing equation. 2H 2 + O 2 → 2 H 2 O What do you think is the relationship between number of moles and the volume of gaseous reactants and products in a reaction? (2L)+(1L) → (2L)

ESSENTIAL QUESTION How are the number of moles related to the volume of reactants and products in a chemical equation?

GAS VOLUMES AND THE IDEAL GAS LAW Gay Lussac’s law of combining volumes of gases At a constant temperature At a constant pressure Volumes can be expressed as ratios of small whole numbers What does this law mean to you?

MOLAR VOLUME OF A GAS The volume occupied by one mole of a gas at STP is known as the standard molar volume of a gas. 1mol = 22.4L

AVOGADRO’S LAW Avogadro’s law states that Equal volumes of gases At the same temperature At the same pressure Contain equal number of molecules

PRACTICE How many moles are contained in L of Ne at STP? 3.50 mol Ne

PRACTICE What is the volume in liters of 0.87 mol of chlorine gas (Cl 2 ) at STP? L Cl 2

PRACTICE How many atoms are contained in L of Xe at STP? 4.52 X atoms Xe

PRACTICE How many liters are contained in 1.75 mol of F 2 gas at STP? 39.2 L F 2

PRACTICE How many liters are contained in 3.60×10 24 molecules of O 2 at STP? 1.34 X L O 2

PRACTICE What is the mass in grams of 4.03 x H 2 molecules at STP? 1.35 g H 2

PRACTICE What is the mass in grams contained in L of NO 2 at STP? g NO 2

DO NOW What volume does mol of gas occupy at STP? What quantity of gas, in moles, is contained in 2.21 L at STP?

THE IDEAL GAS LAW The ideal gas law is the mathematical relationship among pressure, volume, temperature, and the number of moles of a gas.

IDEAL GAS CONSTANT R is known as the ideal gas constant The gas constant is determined by the units of pressure Unit of RValue of RUnit of Pressure L.mm.Hg mol.K 62.4mmHg L.Atm Mol. K atm J mol.K 8.314Pa L.kPa Mol.K 8.314kPa

PRACTICE What pressure in atmosphere is exerted by mol of hydrogen gas in a 4.08 L container at 35 0 C? 2.01atm

PRACTICE A gas sample occupies 8.77 L at 20 0 C. What is the pressure, in atmospheres, given that there are 1.45 mol gas of sample? 3.98 atm

DO NOW 1.How many moles of oxygen will occupy a volume of 2.5 liters at 1.2 atm and 25 0 C ? 2.What volume will 2.0 moles of nitrogen occupy at 720 torr and 20 0 C ? 3.What pressure will be exerted by 25 g of CO 2 at a temperature of 25 0 C and a volume of 500 mL ? Use the Ideal Gas Equation to answer the following questions.

DO NOW Explain the difference between gas effusion and gas diffusion, provide examples with your answer.

DETERMINATION OF MOLAR MASS FROM THE IDEAL GAS EQUATION A variation in the ideal gas equation replaces n, with m_ MM This substitution is useful in determining factors such as: Density (m/v) Molar Mass (mass of the gas) Mass of the sample (sample given) Molar Volume (MV)