CHE 101 Lecture outlines Chapter 10Chapter 10: Gases Material to Learn on Your Own I do not have time to cover Sections 10.1-10.2 in lecture. A Pre-recorded lecture is located on UB Learns, located: • Gulde Folder-PreRecorded Folder-Chapter10_IntroGases– You MUST watch this prior to next lecture!! Turn to Page 3 “Gas Laws” of lecture NotesGas Substances Air: _________________________ of many gases Common gases: Usually have ___________________________ Noble gases Diatomics  Ozone (O3) Molecular compounds• Ex: CO, CO2, N2O Solids or liquids can be forced to exist as gases called ________________________ Ex. H2OPhysical Characteristics of Gases1. Automatically take the _________________ & _____________________ of its container Molecules are ________________________________________ in a gas than either asolid or a liquid- Lots of ______________________________ between molecules2. Highly _____________________________  Able to _______________ gases into _____________________ volumes3. Always make ________________________________ mixtures (___________________)1CHE 101 Lecture outlines Chapter 10Gases Exert Pressure Pressure (P) – __________________ exerted by molecules in motion  ____________________ pulls atmospheric gases to Earth’s surface• Exerting ___________ psi (lbs/in2)- Perspective: car tires usually _________________ psi• Felt _______________________ How come we aren’t crushed under this pressure?• Pressure _____________________ our bodies____________________ this pressure SI Unit = Pascal (Pa)  Pascal proposed atmospheric pressure _______________________ w/_________________ altitude Other common units: Atmospheres (atm) = pressure at __________________ & ____________ = • 1 atm = 1 x105 Pa Millimeter of mercury (mmHg) = from barometer• Also known as torr (Torricelli invented barometer) - 1 mmHg = 1 torr - 1 atm = 760mmHg• If increase Air Pressure- Height ___________________2CHE 101 Lecture outlines Chapter 103CHE 101 Lecture outlines Chapter 10Gas Laws 4 variables describe gases: Pressure __P_____ Volume ____V___ Temperature ___T____ Amount __(n)_____ = # of ___moles__________1. Bolye’s Law : P & V If pressure increases, volume _______decreases_________________ • P µ __1/V______ (@ constant n and T)• ____PV______ = constant 2. Charles’s Law : V & T If increase temp, volume ______increases_____________________ • Think _______hot air______________ balloon  V µ __T____ (@ constant n and P)• ___V=T________(constant)- Temp must be in ___Kelvin____________ 3. Avogadro’s Law : V & n NOTE: 1st proposed by Louis Gay-Lussac, but better interpreted by Amedeo Avogadro If increase moles, volume ________increases____________________- Think ________blowing up___________________ a balloon V µ ___n___ (@ constant T and P)• ____V=n________(constant)4CHE 101 Lecture outlines Chapter 105CHE 101 Lecture outlines Chapter 10Gas Constant What is the constant in each Gas Law? Rewritten:1. Boyle’s: PV = constant PV = R2. Charles's V = T constant V = TR3. Avogadro’s: V = n constant V = nR Ideal (universal) gas constant = ___R_____ How do you know which to use?- Depends on the ____units___________Ideal Gas Law Combines all 3 gas laws into 1: PV=nRT Required _____units____________ for this equation: P = _____atm_____________ V = ______L___________ n = _____moles_____________ T = _______K___________• TK=TC + 273Question10.1: Which value of the gas constant should always be used with the Ideal Gas Law?A. 0.08206B. 8.3146R = 0 . 08206 L⋅ atmmol⋅KorR=8 .314Jmol⋅KCHE 101 Lecture outlines Chapter 10Standard Temp. & Press. FOR GASES! Standard Temperature & Pressure _________ – special set of conditions Temperature = ___0oC______ Pressure = ___1.00 atm_________  If have 1.00 mole of gas at STP what is the volume? Standard molar volume = ____22.4L______________Sample Problem If 12.3g of steam is confined to 18.0 mL, what is the temp (C) if the pressure is 1.75x106torr?PV=nRT12.3 g H2O / 18.02 g= .683 mols H2O18 mL= .0180 L1.75x10^6 Torr= 2.30x10^3 atmT=(2300 atm)(.0180 L)/(.683 mol)(0.0826)T=739K = 466 o C7CHE 101 Lecture outlines Chapter 108CHE 101 Lecture outlines Chapter 10Combined Gas Law Combined Gas Law – shows relationships for the __________ gas at different ______________________ Use Ideal gas equation & make a _________________________________ • Solve for what’s _________________________ & set that ____________ to each other • GENERIC example:Sample Problem A 5.50 L volume of gas has a pressure of 0.950 atm at 25C. What is the volume if the gas is at STP? Question:10.2: The pressure in a balloon is maintained at 2.20 atm. On a day when the temperature is -15C, the volume of gas in the balloon is 3.25x103 m3. What is the volume of the same quantity of gas on a day when the temperature is 31C? Which equation is best to use?A. PV=nRT C. B. D. 9PV=nRTCHE 101 Lecture outlines Chapter 10Molar Mass & Ideal Gas Law (Exp. 10) Can find Molar mass (Mm) of unknown gas: Substitute into Eq: PV=nRT Solve for Mm:Density & Ideal Gas Law Can also determine the density of a gas: Close look at Mm eq: Solve for d: Note correlation when P & T are constant:• _________________ Mm, the ___________________ the density• Picture conditions: 1atm & 15C10Mm=gramsmolunits Mm=mnsolve for nd=mVCHE 101 Lecture outlines Chapter 10Sample Problem1. What is the density of CO2 at 745 torr and 65C?Gases in Chemical Rxns (Stoichiometry) Use ______________________________________ to relate information between reactants & products Note: to use gas law, compound MUST BE a ________________!11CHE 101 Lecture outlines Chapter 10Sample Problems1. Air bags in cars are inflated by the decomposition of solid sodium azide (NaN3) to form nitrogen gas. If 74.0g NaN3 at 26C decomposes resulting in an air bag having a volume of 36L, what is the resulting gas pressure?2NaN3(s)  2Na(s) + 3N2(g)2. If 3.07L of oxygen gas at 0.993atm burns with liquid methane (CH4) in a 250.0mL flask to produce carbon dioxide and liquid water at 297K, what is the pressure of CO2 that is produced?12CHE 101 Lecture outlines Chapter 10Gas Mixtures Gases usually found as ________________________ (ie. Air) Partial Pressure – each gas in a mixture exerts its own