Gas Laws V 1 V 2 T 1. Gas Laws.notebook. May 05, T = k P 1 V 1 = P 2 V 2. = 70 kpa. P. V = k. k = 1 atm = kpa

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1 Gas Laws At constant temperature, all gases behave the same when compressed As increasing pressure is applied to a gas in a closed container, the volume of the gas decreases he product of pressure and volume is always constant P 1 V 1 = P 2 V 2 P. V = k Why does the plunger bounce back? Use the terms: particles collisions Walls of container plunger he gas in a balloon has a volume of 7.5 L at 100 kpa. he balloon is released into the atmosphere, and the gas in it expands to a volume of 11 L. Assuming a constant temperature, what is the pressure on the balloon at the new volume? List what you know Write the formula Solve for the variable you need Plug 'n chug P 1 V 1 = P 2 V 2 1 atm = kpa 70 kpa = Standard Pressure (at sea level) = 70 kpa Graph Jacques Charles discovered that the volume of a gas is directly proportional to its temperature (Kelvin scale) At constant pressure, the volume of a gas divided by its absolute temperature is constant. V = k k = V V 1 V 2 1 = 2 Why does the plunger go up as the temperature increases? _,_KE,_V, _Collisions, _Pressure 1

2 A sample of gas occupies 24 m 3 at K. What volume would the gas occupy at K? List what you know 55m 3 K o C o F Write the formula water Solve for the variable you need Answer Plug 'n chug freezes Write a formula that will convert o C to K o C? K? =?? o C = K Answer D D 1. A syringe has a sample of gas with a volume of 3.95 ml at a pressure of 1.00 atm. What is the pressure of the gas in the syringe if the volume is changed to 2.53 ml? 1.56 atm 2. A partially inflated weather balloon has a volume of 1.50 x 10 3 L at 98.8 kpa of pressure. What is the volume of the balloon when it is released to a height where the pressure is 44.1 kpa? = 3,360 L 3.36 x 10 3 L 3. A sample of gas has a volume of 852 ml at 198 K. What volume does the gas occupy at 293 K? 1260mL 4. A sample of gas has a volume of L at a temperature of 23 o C. What temperature is necessary to have a volume of L? 252 K or 21 o C 1. A syringe has a sample of gas with a volume of 3.95 ml at a pressure of 1.00 atm. What is the pressure of the gas in the syringe if the volume is changed to 2.53 ml? List what you know Write the formula Solve for the variable you need Plug 'n chug 2. A partially inflated weather balloon has a volume of 1.50 x 10 3 L at 98.8 kpa of pressure. What is the volume of the balloon when it is released to a height where the pressure is 44.1 kpa? 3. A sample of gas has a volume of 852 ml at 198 K. What volume does the gas occupy at 293 K? A sample of gas has a volume of L at a temperature of 23 o C. What temperature is necessary to have a volume of L? 252 K or 21 o C o C = K 2

3 H/W: p Gas Laws.notebook Gay Lussac discovered that the pressure of a gas is directly proportional to its temperature (Kelvin scale) At constant volume, the pressure of a gas divided by its absolute temperature is constant. P = k k = P P 1 P 2 1 = 2 P V Pe Uncle Larry tells his nephews to never throw paint cans into the fire. "Why?" they ask. "I'll show you." Uncle Larry builds a bonfire. "Get ready to run," he warns. he can is rated to 9.00 atm before bursting. he temperature inside the can reaches 414 o C after being in the fire for 17 sec. he temperature before being thrown recklessly was 72 o C., with a pressure of 7.00 atm. Will it burst? Show work. H/W: p p. Uncle Larry tells his nephews to never throw paint cans into the fire. "Why?" they ask. "I'll show you." Uncle Larry builds a bonfire. "Get ready to run," he warns. he can is rated to 9.00 atm before bursting. he temperature inside the can reaches 414 o C after being in the fire for 17 sec. he temperature before being thrown recklessly was 72 o C., with a pressure of 7.00 atm. Will it burst? Show work. Boyle's Law + Charles' Law + Gay Lussac's Law = Combined Gas Law P 1 V 1 P 2 V 2 1 = 2 P V 3

4 A weather balloon containing helium with a volume of L rises in the atmosphere and is cooled from 27 o C to 27 o C. he pressure on the gas is reduced from kpa to 25.0 kpa. What is the volume of the gas at the lower temperature and pressure? H p p p A weather balloon containing helium with a volume of L rises in the atmosphere and is cooled from 24 o C to 31 o C, and increases in size to 989 L. he pressure on the gas changes from kpa to what new pressure? 1 atm = 101,325 Pa = kpa 1 atm = 760 mm Hg SP = SANDARD EMPERAURE AND PRESSURE P 273K SP = SANDARD EMPERAURE AND PRESSURE 1 atm = 101,325 Pa = kpa 1 atm = 760 mm Hg 4

5 1. A gas has a volume of 18.5 L at 85.5 kpa and 296 K. What is the volume of the gas at SP? 1 atm = 101,325 Pa = kpa 1 atm = 760 mm Hg 2. A balloon full of helium gas has a volume of 132 L at 99.7 kpa and 30 o C. What temperature is required for the balloon to have a volume of 176 L at a pressure of 77.6 kpa? 3. A plastic bag is inflated to a volume of 3.89 L at atm and 23 o C. If the volume drops to 3.05 L at a temperature of 4 o C, what is the new pressure? SP = SANDARD EMPERAURE AND PRESSURE 273K 1. A gas has a volume of 18.5 L at 85.5 kpa and 296 K. What is the volume of the gas at SP? 2. A balloon full of helium gas has a volume of 132 L at 99.7 kpa and 30 o C. What temperature is required for the balloon to have a volume of 176 L at a pressure of 77.6 kpa? 3. A plastic bag is inflated to a volume of 3.89 L at atm and 23 o C. If the volume drops to 3.05 L at a temperature of 4 o C. What is the new pressure? p.449#4 A sample of carbon dioxide gas occupies 45m3 at 750 K and 500. kpa. What is the volume of this gas at SP? V 5

6 Gas Laws.notebook May 05, 2014 A sample of carbon dioxide with a mass of g is placed in a ml container at K. What is the pressure exerted Where: n = number of moles by the gas? R = (8.314 L x kpa) / (mol x K) o solve for P, V,, or the number of moles: P V= n R R = ( L x atm) / (mol x K) 1 atm = kpa Where: n = number of moles R = (8.314 L x kpa) / (mol x K) R = ( L x atm) / (mol x K) 1 atm = kpa Intro Gas La Does he look like a pvnrt? H/W ues. p.436 pp#1 4 p.440# #1 4 Wed. p.451#5 9 hurs. p.462 #27,29,30,44,46 1) How many moles of a gas are in a balloon that has a volume of 15.9 L at a pressure of 149 kpa and a temperature of 28oC? 4/10/14 27) A flexible container with 2.0 L of methyl bromide has an internal pressure of kpa at 25oC. What is the volume of methyl bromide at standard pressure if the temperature remains constant? 2) What mass of ammonia, NH3, is required to fill a L bottle to a pressure of 199 kpa at 25oC? 4/22/13 Where: n = number of moles R = (8.314 L x kpa) / (mol x K) R = ( L x atm) / (mol x K) 1 atm = kpa 29) A child receives a balloon filled with 2.30 L of helium from a vendor at an amusement park, where the temperature is 311 K. What will the volume of the balloon be when the child brings the balloon home to an air conditioned house at 295K? 6

7 Hydrogen peroxide (H2O2) decomposes to water and oxygen (O2) gas. H 2 O 2 (l) H 2 O(l) + O 2 (g) Write the balanced equation for the reaction. After hydrogen peroxide reacts with a catalyst, 36.7 ml of oxygen gas are collected in a room at 22 C and 1.01 atm. Calculate the number of moles of gas that were produced. Calculate the mass of the hydrogen peroxide that must have reacted. 4/11/14 Hydrogen peroxide (H2O2) decomposes to water and oxygen (O2) gas. H 2 O 2 (l) H 2 O(l) + O 2 (g) Write the balanced equation for the reaction. After hydrogen peroxide reacts with a catalyst, 36.7 ml of oxygen gas are collected in a room at 22 C and 1.01 atm. Calculate the number of moles of gas that were produced. Calculate the mass of the hydrogen peroxide that must have reacted. 4/11/14 A g sample of X2(g) has a volume of 30 L at 3.2 atm and 27 C. What is element X? PV = nr PV R = n = = moles X 2 29) A child receives a balloon filled with 2.30 L of helium from a vendor at an amusement park, where the temperature is 311 K. What will the volume of the balloon be when the child brings the balloon home to an airconditioned house at 295K? 283.3g X 2 =? mol X 2 X =? g =? mol X Check the periodic table... What mass of ammonia, NH 3, is required to fill a L bottle to a pressure of 199 kpa at 25 o C? H/W Intro Gas Laws w/s p.451 #5 9 A) A sample of gas has a volume of 852 ml at 189 K. What volume does the gas occupy at 293 K? V 2 = 1320 ml or 1.32 L n = mol 2 = B) How many moles of gas are in a balloon that has a volume of 15.9L at a pressure of 149kPa and a temperature of 28 C? B vo CA Science Standards: Chemistry 3. e. Students know how to calculate the masses of reactants and products in a chemical reaction from the mass of one of the reactants or products and the relevant atomic masses. 4. he kinetic molecular theory describes the motion of atoms and molecules and explains the properties of gases. As a basis for understanding this concept: a. Students know the random motion of molecules and their collisions with a surface create the observable pressure on that surface. 4. c. Students know how to apply the gas laws to relations between the pressure, temperature, and volume of any amount of an ideal gas or any mixture of ideal gases. H 7

8 Gas Laws.notebook May 05, 2014 How many liters of hydrogen gas can be produced 4/22/14 at K and 104 kpa pressure if 20.0g sodium metal is reacted with water according to the following equation? How many liters of hydrogen gas can be produced 4/22/14 at K and 104 kpa pressure if 20.0g sodium metal is reacted with water according to the following equation? Na(s) + H2O(l) > NaOH(aq) + H2(g) hints: balance equation choose which gas law to use solve for volume convert g to moles moles Na moles H2 plug 'n chug 1) Calculate the value of the ideal gas constant, R, if exactly one mole of an ideal gas occupies a volume of liters at 0.00 C and 755 mm Hg 4/23/14 atmosphere pressure. Give R in L kpa/mol K. (1 atm = 760 mm Hg = kpa) Na(s) + H2O(l) > NaOH(aq) + H2(g) hints: balance equation choose gas law to use solve for volume convert g to moles moles Na moles H2 plug 'n chug 1) Calculate the value of the ideal gas constant, R, if exactly one mole of an ideal gas occupies a volume of liters at 0.00 C and 755 mm Hg atmosphere pressure. Give R in L kpa/mol K. (1 atm = 760 mm Hg = kpa) Algebra: 2) Calculate Percent Error: (not NOaH) R = Plug 'n Chug: R = Answer: R = 2) Calculate Percent Error: Calculate the mass of carbon dioxide that would be needed to fill a 2.00 L bottle at C and 757 mm Hg. 4/24/14 (1 atm = 760 mm Hg = kpa) 1) Calculate the mass of carbon dioxide that would be needed to fill a 2.00 L bottle at C and 757 mm Hg. 4/24/14 (1 atm = 760 mm Hg = kpa) 8

9 Dalton's Law of Partial Pressures he total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases: P total = P A + P B + P C = P A = P B = P C Disappearing oys: DRY ICE CO 2 (s) CO 2 (g) "Sublimation" ry: (1) Not getting frostbite! (2) Air hockey on your desk (3) Coin torture (4) Bubbling witch's brew (5) Misdemeanor (let Rongley do it instead!), _ P Ice: 0 0 C Dry ice: C ( F) Liquid Nitrogen: 196 C ( 321 F or 77 K) Each gas behaves as if the other gases are absent Start: p.451#5 9 5) 1,100 kpa 6) 0.39 L N2 7) n=0.122 mol N2 D =? 9) 1 psi = kpa V 2 = L He # ballons =? 2. A g sample of X2(g) has a volume of 30 L at 3.2 atm and 27 C. What is element X? Step 1: Convert C to Kelvin = C = = 300. K Step 3: Find mass of 1 mol of X2 4 mol X2 = g 1 mol X2 = 70.8 g Step 4: Find mass of 1 mol of X 1 mol X2 = 70.8 g 1 mol X = 35.4 g Step 5: Identify the element with molecular mass 35.4 g Chlorine has a molecular mass of 35.4 g Answer: Element X is Chlorine Step 2: Solve Gas Law equation for n n = PV R n = (3.2 atm)(30 L) (0.08 atm L/mol K)(300 K) 8) 5.3 x 10 3 mol SO2 9