Chemistry: It’s a Gasgenchem1csustan.wdfiles.com/local--files/start/chapter6clicker2.pdf ·...
Transcript of Chemistry: It’s a Gasgenchem1csustan.wdfiles.com/local--files/start/chapter6clicker2.pdf ·...
Theozone(O3)layerprotectsusfromharmfulultravioletradiation.UVradiationcausesskincancerandcataracts.Chlorofluorocarbonsusedinairconditionersandhairspraycausetheozone layertobedepletedaroundthepolesoftheplanet.
Globalwarmingisduetomoleculestrappingheatinthetroposphere. Carbondioxide,waterandmethanegasesalltrapheatandwarmuptheplanet.
What is causing the planet to warm up?
A. Increasedcarbondioxideemissionsfromburninghydrocarbons.B. Increasedanimalproductdiets.C. Increasednumberofhumansontheplanet.D. Alloftheabove.E. Noneofthese, theearthiscoolingoff
Writedownonethingyoucandotodecreaseglobalwarming.
What is the relationship between atmospheric pressure and altitude?
Asaltitude increases,pressure:A. IncreasesB. DecreasesC. StaysthesameD. Thereisnorelationship
More gas molecules = more pressure
Pressure is a force applied to an area.More molecules create more collisions against the walls of the container.More collisions= more force.
Why are there more gas molecules at sea level than at the top of Mount Everest?A. Gravity pulls the molecules close to
earthB. The temperature is lower at sea levelC. Gas has less buoyancy at sea levelD. The temperature is lower at the top of
Mount Everest.E. None of these.
What is the relationship between the volume and the number of moles of a gas?
V=kn
Atconstanttemperature andpressure,asthenumberofmolesincreases:A.ThevolumedecreasesB.ThevolumeincreasesC.ThevolumestaysthesameD.Noneofthese
Avogadro’s Law:Ifpressureandtemperature areconstant,whatisthenewvolumeif1.2molesina2.4Lballoonhas5.3molesofgasadded?A. 11LB. 13LC. 10.6LD. 19LE. 0.077L
V1 =2.4LV2=Xn1 =1.2molesn2 =1.2+5.3=6.5moles
2.4L = X.1.2moles6.5moles
• WhatIstherelationshipbetweenpressureandtemperature?
• Atconstantvolumeandnumberofmolesofgas,pressureisdirectlyproportionaltotemperature.
• IfPincreases,Tincreases:P =kT
Amonton’s Law
CombinedGasLawAtconstantnumberofmolesofgas(anygas)P1V1=P2V2T1 T2
StandardtemperatureandpressureT=273K,P=1atm
WhatisthevolumeofagasatSTP,ifitoccupies25mLat750mmHgand25°C?
CombinedGasLaw P1V1=P2V2T1 T2
StandardtemperatureandpressureT=273K,P=1atmWhatisthevolumeofagasatSTP,ifitoccupies25mLat750mmHgand25°C?P1= P2=V1= V2=T1 =T2=
P1=0.98atm P2=1atmV1=25mL V2=?T1 =298K T2=273K
SolveforV2=(0.98atm)(25mL)(273) V2 =22.4mL(298k)(1atm)
GasLawsGasLaw Relationship
?Whatisconstant?
Whatequation?
Boyle’sLaw P∝ 1V
Charles’Law
Avogadro’sLaw
Amonton’sLaw
CombinedGasLaw
GaslawsLaw Relationship What is constant Equation neededBoyle’s P∝ 1
Vmoles, temperature P1V1 = P2V2
Charles’ V∝T pressure, moles V1 = V2T1 T2
Avogadro’s V∝n pressure, temperature V1 = V2n1 n2
Amonton’s P∝T volume, moles P1 = P2T1 T2
Combined Use this for converting to STP:273K and 1 atm
moles P1V1 = P2V2T1 T2
Which gas law is related to breathing?A. Amonton’s LawB. Charles’LawC. Boyle’sLawD. CombinedGasLawE. Avogadro’sLaw
Which of the following statements is true?A. As the diaphragm and rib muscles contract, volume
increases, pressure decreases and air flows in.B. As the diaphragm and rib muscles contract, volume
decreases, pressure decreases and air flows in.C. As the diaphragm and rib muscles contract, volume
decreases, pressure increases and air flows out.D. As the diaphragm and rib muscles contract, volume
increases, pressure decreases and air flows out.E. None of these.
When a 2.0 L weather balloon goes from sea level (1 atm, 23°C) to 10 km the pressure decreases to 0.495 atm and the temperature -18°C. What is the new volume?
A. 3.48LB. 0.85LC. 1.15LD. -2.81LE. Noneofthese
Usethecombinedgaslaw.
2.0Lx1atm =0.495atm xVolume296K 255K
255Kx2.0Lx1atm =Volume296Kx.495atm
Idealgaslaw:PV=nRTR=0.0821 Latm
moleKHowmanymolesofgasarepresentina3.2Lcontainerat30°Cand750mmHg?PV=nRTDividebothsidesbyRT:PV =nRT
A. 1.28moles.B.974moles.C.0.127molesD.0.14molesE.noneoftheseRemembertoconvertmmHgtoatm (760mmHg=1atm)and°CtoK,(273+°C=K)
MolarMassofaGasAnexperimentshowsthata0.495gsampleofanunknowngasoccupies127mLat98°Cand754torr pressure.Calculatethemolarmassofthegas(hint:M =mass/numberofmoles).
V =127mL=0.127LP =754torr =0.9921atmT =98°C=371Km=0.495gR=0.0821Latm/moleKM =?
PV = nRT PV = nRT
0.9921 atm x 0.127 L. = n0.0821 (Latm/moleK)371Kn = 0.00413 molesM = 0.495 g/.00413 molesM = 119.85 g/mole