1. If you have 4.00 moles of hydrogen gas at 27°C and kPa of pressure, what is the volume? 2. Also, get your notes out on your desk. Day L

What mass of chlorine gas in grams is contained in a 10.0 L tank at 27°C and 3.50 atm of pressure? 101 g

What is the volume occupied by 4.67 moles of H 2 at 27.0 °C and 2.00 atm.? On notes page L

How much is a mole of water? How could we measure out one mole of water (in this lab)? How much is one mole of air? How could we measure out one mole of air (in this lab)?

The Gas Laws Dalton’s Law of Partial Pressures: – the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases. P T = P 1 + P 2 + P 3 + P 4 …

Oxygen is collected by water displacement at 35°C. The total pressure of gases is 321 mm Hg. What is the pressure of the oxygen? (the pressure of water vapor at 35°C is 23.8 mm Hg) The Gas Laws

If a sample of gas contains CO 2, O 2, and CO, and you know the pressure of O 2 is 200. mm Hg, and the pressure of CO is 250 mm Hg, what is the pressure of CO 2, if the total pressure is 700. mm Hg? The Gas Laws

DAY At 300 K a sample of gas occupies 5 L, if the volume is decreased to 2 L what is the new temperature? V 1 /T 1 = V 2 /T 2 2. Describe Dalton’s law.

If a sample of gas contains CO 2, O 2, and CO, and you know the pressure of O 2 is 0.5 atms., and the pressure of CO is Pa, what is the pressure of CO 2, if the total pressure is 760. mm Hg? The Gas Laws – Back of Notes If a sample of gas contains CO 2, O 2, and CO, and you know the pressure of O 2 is 0.5 atms., and the pressure of CO is Pa, what is the pressure of CO 2, if the total pressure is 760. mm Hg?

A mole is a ___________, plus it relates to ________. ONE MORE THING… IT RELATES TO VOLUME! …FOR GASES counter mass

Avogadro’s law: equal volumes of gases at the same temperature and pressure contain equal numbers of molecules 2H 2 (g) + O 2 (g) 2H 2 O(g) 2 moles 1 mole 2 moles 2 volumes1 volume 2 volumes

Standard Temperature and Pressure (STP) 1 atm and K IF conditions are not specified, assume STP

Standard molar volume of a gas: the volume occupied by one mole of gas at STP = L = dm 3 Conversion factors: 1 mol22.414L L 1 mol

Particles Molecules Atoms Mass (grams) Volume (liters) MOLES Avogadro’s # e23 Molar mass Molar Volume – 22.4 L/mol

Is the volume of a mole the same for all liquids at STP? Is the volume of a mole the same for all solids at STP? So why is the volume of a mole the same for all gases at STP? NO – the size of the particles matters! Size of the particles does NOT matter because most of the volume is empty space.

A chemical reaction produces mol of oxygen gas. What volume in liters is occupied by this gas sample at STP? 1.52 L O 2

1. A mole… I. Can count the # of atoms II. Can count the # of molecules III. Can tell you how much mass you have IV. Is a universal unit Choose all that apply! Day 6 4-6

A chemical reaction produces 98.0 mL of sulfur dioxide gas at STP. What was the mass of the gas produced (this one is on the extra NOTES PAGE – complete it there)? g

896 dL of CO 2 gas contains how many atoms (this one is on the extra NOTES PAGE – complete it there)? 7.23 X 10 24

Key Concepts Particles in a gas are considered to be small, hard spheres with an insignificant volume. The motion of the particles in a gas is ______, ________, and ________. All collisions between particles in a gas are perfectly _______. Gas __________ is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object. The Kelvin temperature of a substance is ______ __________ to the average kinetic energy of the particles of the substance. rapid random constant elastic pressure directly proportional

The Combined Gas Law How are the pressure, volume, and temperature of a gas related?

The Combined Gas Law There is a single expression, called the combined gas law, that combines Boyle’s law, Charles’s law, and Gay- Lussac’s law. P1  V1P1  V1 T1T1 T2T2 P2  V2P2  V2 =

cartesian divers How does a cartesian diver work?

Tuesday 4-12

Boyle’s Law Ideal Gas Kinetic Energy Mole Standard Temperature and Pressure Attract Volume-temperature relationship Absolute zero Charles’ Law Avogadro’s Law Pascal Precipitate Synthesis reaction

#s 31, 32, 34, 35, 36, and 38 on pages

1520 mm Hg = ____ atms.  Use your notes to find the equivalence line. Day A sample of gas that contains 8.0 moles at 300K and 3 atms. takes up how much space?

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Graham’s Law How does the molar mass of a gas affect the rate at which the gas diffuses or effuses?

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Graham’s Law Diffusion is the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout.

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A cylinder of air and a cylinder of bromine vapor are sealed together. Bromine vapor diffuses upward through the air. After several hours, bromine vapors reach the top of the column. Graham’s Law

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. During effusion, a gas escapes through a tiny hole in its container. With effusion and diffusion, the type of particle is important. Graham’s Law

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Gases of lower molar mass diffuse and effuse faster than gases of higher molar mass. Graham’s Law

This law can also be applied to the diffusion of gases. If two objects with different masses have the same kinetic energy, the lighter object must move faster. Thomas Graham’s Contribution Graham’s law of effusion states that the rate of effusion of a gas is inversely proportional to the square root of the gas’s molar mass. Graham’s Law

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Molecules of helium have a lower mass than the average mass of air molecules, so helium molecules effuse through the tiny pores in a balloon faster than air molecules do. CHEMISTRY & YOU Why do balloons filled with helium deflate faster than balloons filled with air?

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Rate A Rate B = molar mass B molar mass A Because the rate of effusion is related only to a particle’s speed, Graham’s law can be written as follows for two gases, A and B. Graham’s Law

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. How much faster does helium (He) effuse than nitrogen (N 2 ) at the same temperature? Sample Problem 14.8 Comparing Effusion Rates

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Calculate Solve for the unknown. Start with the equation for Graham’s law of effusion. Rate He Rate N 2 = molar mass N 2 molar mass He Sample Problem 14.8

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Calculate Solve for the unknown. 2 Substitute the molar masses of nitrogen and helium into the equation. Rate He Rate N 2 = 28.0 g 4.0 g =7.0= 2.7 Sample Problem 14.8

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Helium atoms are less massive than nitrogen molecules, so it makes sense that helium effuses faster than nitrogen. Evaluate Does this result make sense? 3 Sample Problem 14.8

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Which of the following gas particles will diffuse fastest if all of these gases are at the same temperature and pressure? A.SO 2 C.N 2 O B.Cl 2 D.Hg

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A.SO 2 C.N 2 O B.Cl 2 D.Hg Which of the following gas particles will diffuse fastest if all of these gases are at the same temperature and pressure?

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Key Equations Dalton’s Law: Graham’s Law: Rate A Rate B = molar mass B molar mass A P total = P 1 + P 2 + P 3 + …

Tuesday 4-12

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 1.Is the boiling point of water at the top of Mount McKinley (the highest point in North America) higher or lower than it is in Death Valley (the lowest point in North America)? EXPLAIN!

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A tank used by scuba divers has a P total of 2.21  10 4 kPa. If P N 2 is 1.72  10 4 kPa and P O 2 is  10 3 kPa, what is the partial pressure of any other gases in the scuba tank (P other )? P total = P O 2 + P N 2 + P others P others = P total – (P N 2 + P O 2 ) P others = 2.21  10 4 kPa – (1.72  10 4 kPa  10 3 kPa) P others = 2.59  10 2 kPa PRACTICE

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Dalton’s Law Gas pressure results from __________ of particles in a gas with an object. If the number of particles increases in a given volume, ______ collisions occur. If the average kinetic energy of the particles increases, ______ collisions occur. In both cases, the pressure ___________. collisions more increas es

Boyle’s Law Ideal Gas Kinetic Energy Mole Standard Temperature and Pressure Attract Volume-temperature relationship Absolute zero Charles’ Law Avogadro’s Law Pascal Precipitate Synthesis reaction

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 1.Energy of motion (or kinetic energy) depends on … 2. Which noble gas should effuse the fastest? Why? Whose law?

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. REVIEW In a mixture of gases, the total pressure is the _____ of the partial pressures of the gases. Gases of lower molar mass diffuse and effuse ________ than gases of higher molar mass. sum faste r

33,600 mL of Helium = ____ atoms at STP 9.03 X 10 23

1. At 100 K and 1 atm a sample has a volume of 2L, if the gas expands to 6L what is the new temperature? 300K

Specifically explain what happened in Part A of your lab AND why (it might help to get your lab out).

Tuesday 4-12

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 1.Explain how the can was crushed in the gas laws lab.

Tuesday 4-12