Gases Grape Plasma. October 27, Gases Notes Blank notebook

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1 On desk! RG 14 Due, Phase WS on desk! WU: FYI Plasma is the other form of maer similar to gas in which a certain poron of the parcles are ionized. Can be found in stars, most of space, and seen as lightning, solar flares, aurora, etc. Gases Grape Plasma 4 states of Matter song! How can a phase diagram be used to explain why water can be boiled at a lower temperature in Denver? Inc P, inc T at which it boils (higher bp temp) Dec P, dec T at which is boils (lower bp temp) Pressure and Volume Relationship Quick Lab books and blue pippette Review what you discovered yesterday!!1 Pressure, Temperature, and Volume Relationship You CAN do it Quick Lab YES GOOGLES!!! Step 1: Get hot plate and a soda can add a small amount of water to the bottom of the can and BOIL! Step 2: Prepare an ice bath in a mL beaker Step 3: Once you see vapors coming out of boiling can, use BEAKER TONGS to grab can and flip it over (mouth side upside down) into the ice bath submerge it fully! Explain as much as you can about what occurred! Avogadro s Law Boyle s Law Charles s Law? Temperature and Volume Quick Lab dye and hotplate Mar 24 10:31 AM 1

2 Gay-Lussac s Law Combined gas Law Atmospheric Pressure Roughly equivalent to the force of an elephant balancing on a desk! Variables used to describe gases: Pressure (P) ~ Caused when gas particles collide with the sides of their container ~ Units: atmospheres (atm) kilopascals(kpa) millimeters of mercury (mmhg) 1.0 atm = kpa = mmhg Volume (V) ~ How much space the gas is occupying ~ Measured in ml or L Temperature (T) ~ Avg. KE of the substance ~ For gases must be expressed in Kelvins C = Kelvin Amount (n) moles Measuring Gas Pressure or Atmospheric Pressure Mar 22 10:36 AM 2

3 Measuring Gas Pressure Mar 21 4:24 PM Measuring Gas Pressure Measuring Gas Pressure 3

4 Example of the amount of work I want to see. At 700. mmhg a sample of hydrogen has a volume of 500.mL. If the pressure is decreased to 538 mmhg, what will the new volume be? Practice with the Gas laws Prx #1 16 and on Problem Set 14 Mar 17 3:16 PM WU: Check your #1 16 Gas Law Questions Gas Laws Foldable (Use Ch 14) 1. Take a piece of paper and fold in lengthwise (hot dog style), cut the paper in half along the fold. Take the 2 strips of paper, stack and fold them hamburger style and staple on the fold. You should have a booklet with 4 pages. 2. Title Page: Gas Laws. Take your foldable and open it to the irst inside page. Onto each page you will copy each item listed below as a heading. Boyle s Law Charles Law Gay Lussac s Law Combined Gas Law Ideal Gas Law Dalton's Law Graham's Law 3. For full credit, include the following info on each page: Deinition Direct or Inverse Proportion (for the 1 st 3 laws) Formula Example of this occurrence in real life Sample problem 4. On the front cover page, please include o o o Equation used to convert from C to Kelvin. Standard Temperature Standard Pressure 5. Full credit will also include effective use of color Write out all 5 gas laws and the units you would expect with each variable. KMT SAS in Schools Webquest after IGL Notes and Gas Stoich PS 13 Review Oct 27 11:24 PM Mar 17 3:13 PM 4

5 What is a theory? A proposed model to explain phenomena in nature to best ability. Kinec Molecular Theory of Gases describes an Ideal gas Ideal gases have no volume (space occupied insignificant) Real gases: Ideal gases parcles are in constant random moon Real gases: Ideal gas parcles have elasc collisions (no KE lost) Real gases: For an ideal gas, Kinec energy is proporonal to Kelvin Temperature Real gases: Ideal gas parcles do not aract or repel each other Real Gases: Real Gases exist at High P or Low T (b/c compressed and opposed KMT) KMT Explains Properes of a Gas Low density (mass per vol) Compression (dec. space btw atoms) and expansion (inc. space btw atoms) Diffusion (mvmt of parcles, velocity varies) Effusion (through a hole, rate depends on molar mass) The Gas Laws Ideal gas Law: Derived from the KMT PV= nrt R : universal gas constant When using the ideal gas law, you will need to convert units to match the universal gas constant P in V in Amount in Temp in 5

6 IGL Problems #17, 18, 19 on Lecture Notes Ans: #17 = mol, g #18 = 620kPa #19 = 663 g/mol Stoichiometric Calculaons with Gases: Volume condions of unchanging temperature and pressure : Ex. 2H 2 + O 2 2H 2 O If 5.0 L of hydrogen react with 4.0 L of oxygen, how many liters of water vapor are formed? Mass (non gaseous substance) to Volume Gas gx to mol X to mol gas to V= nrt/p Volume gas Mass STP 1 mol gas = 22.4 L gas Examples When potassium chlorate decomposes at 755 mmhg and 23.0ºC, 42.6 ml of the gas is collected. How much potassium chlorate must have decomposed if none of the gas was non STP.Moles gas n= PV/RT to moles X to gx 6

7 Ideal Gas Law Lecture Problems 1. When 4.50 g of magnesium chlorate decomposes at 800. C, 5.94L of the gas is collected at 774.0mmHg. What is the percent yield for the reaction? g of magnesium is placed in 150.0mL of 0.100M hydrochloric acid. What volume of gas could be collected at 25.0 C and 742.0mmHg. If a student captures 149.0mL, what is the students percent yield? Mar 24 10:59 AM Mar 24 10:59 AM 3. How many grams of nitrogen are needed to produce 48.6 liters of ammonia (NH3) at 10.0 C and 70.91Kpa? 4. An unknown metal having a 2 + oxidaon state with a mass of 0.033g is reacted with excess sulfuric acid ml of gas was collected at 23.0 C and 755.0mmHg. What is the molar mass of the metal? Identify the metal. Mar 24 10:59 AM Mar 24 10:59 AM 7

8 5. What volume of chlorine gas at 20.0 C and 0.92 atm is needed to react with 4.60 g of sodium metal to form sodium chloride? What is the theoretical mass of sodium chloride that could be formed? WU: Questions on IGL HW? Write this down then Gas Law Quiz 5 questions? Dalton s Law Paral Pressure Atmospheric Pressure comes from the pressure of many gases: ~ ~ ~ Mar 24 11:00 AM Molar Mass of Butane Lab WATCH BEFORE LAB! Goggles, shoes, aprons, hair back, etc Need electronic balance, 100mL grad cylinder, lighter (FROM ME!), calculator Pneumonic trough = water container Take all plastic off grad cylinder before use Dispose of butane appropriately!! Write down: P atm = 29.00inHg ; 1in= 2.54cm (conv factor) Come get water vapor pressure from me for your temperature of water. Water Vapor Pressure: What happens if you don't get rid of all the butane Finish PS 14 (except for Graham's Law) Mar 29 1:37 PM Mar 29 4:51 PM 8

9 Graham s Law The rate of effusion of any gas is inversely proporonal to the square root of its molar mass. Examples: What is the relave velocity (rate of effusion) of hydrogen gas to carbon dioxide gas? Effusion is: Formula: An unknown elemental gas effuses at 4.5 mes the rate of krypton gas. What is the molar mass of the gas? What is the identy of the gas? Graham s Law Lab Diffusion of gases 9

10 Why important?? Mar 27 5:35 PM Mar 31 10:58 AM Grahams Law Procedure: Tear about 1/2 cotton from Qtip ends (make sure it fits snug in the glass tube) Break Qtip in 1/2 1 person add chemicals to both Qtip ends (1 person hold while other adds chemicals) Immediately stick Qtips in tube! Set glass down and wash hands! Wait few mins for results... complete questions while waiting. Review Day Complete all Unit Review for Extra Credit! PS 14 Totally 100% complete tomorrow! Mar 29 8:35 AM 10

11 1) Is boiling a warming or cooling process? 2) Is sweating a warming or cooling process? 3) Does adding KE to particles allow them to transform from liquid to gas or gas to liquid? Think What will burn you more steam or boiling water? 4) Where does water boil at a higher temperature Here or Mount McKinley (tallest mountain on the continent ; 20,320 feet)? Gases Funs Labs! 1. Water in a cup 2. IGL Alka Seltzer and Balloon Lab Note: The gas pressure inside the balloon is the sum of the P gas + P water vapor so must account for that when calculang Vol of sphere = 4/3 (л x r 3 ) Circumference? Mar 21 4:21 PM Apr 2 5:50 PM Mar 30 6:11 AM Apr 2 5:50 PM 11

12 Attachments Chem PS 13 Key Typed.docx