QUIZ – WED CASTLE LEARNING / EXAM - FRIDAY Other Gas Laws Aim: What other laws help us explain gas behavior? Do Now: Solve the Combined Gas Law Problem on the White Board Homework: Complete worksheet. Show all work. Box in final answers with appropriate units QUIZ – WED CASTLE LEARNING / EXAM - FRIDAY

Avogadro’s Hypothesis… *Gases at the same volume, pressure, & temperature have the same number of molecules

Avogadro’s Law: If temperatue, volume, and pressure are the same for 2 different gases then each gas contains the same # of molecules

Example 1 A 10.0 liter flask at a given temperature and pressure contains 6.0x1023 molecules of hydrogen gas. Under the same conditions of temperature and pressure, how many molecules would a 10.0 liter flask of nitrogen gas contain?  Example 2 At STP, 1 liter of H2(g) and 1 liter of He(g) have the same (a) mass (c) # of atoms (b) density (d) # of molecules

Example 3 At Standard temperature and pressure, 32.0 liters of O2 contain the same number of molecules as: A)    44.8 L of He B)    32. 0 L of H2 C)    28.0 L of N2 D)    22.4 L Ar Correct Answer: Option B 32. 0 L of H2

Explain Avogadro’s Law in your own words

Dalton’s Law Partial Pressure (Easy) Ptotal = P1 + P2 + P3 A container holds three gases: oxygen, carbon dioxide, and helium. The partial pressure of the three gases are 2.00 atm, 3.00 atm, and 4.00 atm, respectively. What is the total pressure inside the container? 9.00 atm Hydrogen gas at a pressure of 1.5 atm is added to Oxygen gas at 2.0 atm. What is the total pressure? 3.5 atm

Dalton’s Law of Partial Pressure (Difficult) Ppart = Ptotal (molespart / molestotal) A tank contains 480.0 grams of oxygen and 80.00 grams of helium at a total pressure of 7.00 atmospheres. Calculate each gas partial pressure. How many moles of O2 are in the tank? 15 moles How many moles of He are in the tank? 20 moles Total moles of gas in tank? 35 moles Partial pressure of O2? 3 atm Partial pressure of He? 4 atm

Dalton’s Law of Partial Pressure (Difficult) Ppart = Ptotal (molespart / molestotal) A tank contains 5.00 moles of O2, 3 moles of neon, 6.00 moles of H2S, and 4.00 moles of argon at a total pressure of 1620.0 mm Hg. Calculate the partial pressure of each gas. O2 = 450 Ne = 270 H2S = 540 Ar = 360 A mixture of 14.0 g of hydrogen, 84 g of nitrogen, and 2.0 mole of oxygen are placed in a flask. When the partial pressure of the oxygen is 78.00 mm Hg, what is the total pressure in the flask? 585 mm Hg

Graham’s Law Relates the rate of diffusion of gases to their molar masses (GFM) Diffusion is movement of gas particles from an area of high concentration to an area of low concentration If someone in a room uses a deodorant spray, it doesn't take long for everyone else in the room to smell it. This is because of diffusion.

Graham’s Law… The GREATER the molar mass (GFM) of a gas the SLOWER it diffuses Gases with small GFM diffuse very rapidly Gases with large GFM diffuse slowly Example: At STP which of the following gases will diffuse most rapidly? (1) Cl2 (2) NH3 (3) CO2 (4) N2

Graham’s Law At constant temperature, SO2 molecules have a velocity of 12.50 m/s. What is the velocity of Hydrogen molecules under the same conditions? 70.36 m/s At constant temperature, sulfur dioxide molecules, SO2 will diffuse in 34 minutes. How long will it take hydrogen molecules (H2) under the same conditions? 6.04

Grahams Law A sample of Xenon effuses through a porous container 9.50 times faster than an unknown gas. What is the molecular mass of this unknown gas? 11849.8 g A sample of Neon effuses through a container 6.50 times faster than an unknown gas. What is the molecular mass of this unknown gas? 853 g

Summary Avogadro's Hypothesis Daltons Law of Partial Pressure Graham’s Law of Effusion