Unit 9 G a s B e h a v io r H o m e w o r k P a c k e t

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Hoffman 2009 Chem- Gas lawsOverall Objective: Understand and apply the properties of gasesand the gas laws.Iowa Model Core standards addressed:o Understands and applies knowledge of the structure and properties of mattero Designs and conducts scientific investigationso Uses technology and mathematics to improve investigations and communicationso Apply critical literacy/thinking skills related to personal, family and communitywellness.o Apply digital tools to gather, evaluate, and use information.Key Concepts:1. Explain why gases are easier to compress than solids or liquids are. (14.1.1)2. Describe the three factors that affect gas pressure. (14.1.2)3. Describe the relationships among the temperature, pressure, and volume of a gas.(14.2.1)4. Use the combined gas law to solve problems. (14.2.2)5. Compute the value of an unknown using the ideal gas law. (14.3.1)6. Compare and contrast real and ideal gases. (14.3.2)7. Understand the effects of CO 2 on the atmosphere and its impact on climate change. Page 2 of 11

Hoffman 2009 Chem- Gas lawsAtmospheric Pressure PracticeThe values for standard atmospheric pressure in different units are as follows:Units of Gas PresureUnitsStandard PressureAtmosphere1 atm (exactly)Inches of mercury 29.9 in. Hgcm of mercury 76 cm Hg (exactly)mm of mercury 760 mm Hg (exactly)torr760 torr (exactlypounds per square inch 14.7 psikilopascal101 kPaIf oxygen gas in a steel cylinder is at a pressure of 5.25 atm, what is the pressure in each ofthe following units?A) mm HgB) torrC) cm HgD) inches HgIf an automobile piston compresses a fuel-air mixture to a pressure of 7555 torr, what is thepressure expressed in each of the following units?A) psiB) kPaAn American newscast states that the barometer reads 28.8 inches of Hg. Express theatmospheric pressure in each of the following units:A) atm B) mm HgC) cm Hg D) torrPage 3 of 11

Hoffman 2009 Chem- Gas lawsIdeal Gas BehaviorState the five characteristics of an ideal gas according to the kinetic theory.At what Celsius temperature does a gas possess zero kinetic energy?Temperature ConversionsConvert the following temperatures to the unit asked for:1) 273K to o C2) 0 o C to o F3) 0K to o C4) 23 o C to o F5) The boiling points of five liquids are provided in either Celsius or Kelvintemperatures. List the liquids in order from the one with the lowest boiling pointto the one with the highest boiling point.Acetone (C 3 H 6 O) 329KHeptane (C 7 H 16 ) 98 o CNitromethane (CH 3 NO 2 ) 374KBenzene (C 6 H 6 ) 80 o CSulfur Trioxide (SO 3 ) 318KPage 4 of 11

Hoffman 2009 Chem- Gas lawsBoyle’s Law PracticeP 1 V 1 = P 2 V 2Sketch a graph of pressure versus volume, assuming temperature is constant. Label thevertical axis V, and the horizontal axis P.A sample of air at 0.750atm is expanded from 250.0mL to 655.0mL. If the temperatureremains constant, what is the final pressure in atm?What is the final volume of argon gas if 2.50L at 750 torr is compressed to a pressure of 150torr? Assume the temperature remains constant.A 1.50 L sample of methane gas exerts a pressure of 1650 mm Hg. Calculate the finalpressure if the volume changes to 7.00 L. Assume temperature remains constant.A 50 mL sample of carbon monoxide gas at 25 o C has a pressure of 15.0 psi. If the finalvolume is 44.0 mL at 25 o C, what is the final pressure in psi.Page 5 of 11

Hoffman 2009 Chem- Gas lawsCharles’ Law PracticeV 1 /T 1 = V 2 /T 2Sketch a graph of volume versus Kelvin temperature, assuming pressure is constant. Labelthe vertical axis V, and the horizontal axis T(K).A 335-mL sample of oxygen at 25oC is heated to 50oC. If the pressure remains constant,what is the final volume in milliliters?What is the final Celsius temperature if 4.50 L of nitric oxide gas at 35oC is cooled until thevolume reaches 1.00 L? Assume the pressure remains constant.A 275 L helium balloon is heated from 20 o C to 40 o C. Calculate the final volume assuming thepressure remains constant.A krypton balloon has a volume of 555 mL at 21 o C. If the balloon is cooled and the volumedecreases to 475 mL, what is the final temperature? Assume the pressure remains constant.Page 6 of 11

Hoffman 2009 Chem- Gas lawsGay-Lussac’s Law PracticeP 1 /T 1 = P 2 /T 2Sketch a graph of pressure versus Kelvin temperature, assuming volume is constant. Labelthe vertical axis P, and the horizontal axis T(K).A sample of ammonia gas at 760 torr is heated from 20 o to 200 o C. If the volume remainsconstant, what is the final pressure in torr?A sample of xenon gas at 20 o C and 0.570 atm is cooled to a pressure of 0.100 atm. If thevolume remains constant, what is the final Celsius temperature.A 1.00-L sample of neon gas at 0 o C has a pressure of 76.0 cm Hg. If the gas is heated to100 o C, what is the final pressure in cm Hg if the volume remains constant?Page 7 of 11

Hoffman 2009 Chem- Gas lawsCombined Gas LawP 1 V 1 = P 2 V 2T 1 T 2A 100.0-mL sample of hydrogen gas is collected at 772 mm Hg and 21 o C. Calculate thevolume of hydrogen at STP.A 5.00-L sample of nitrogen dioxide gas is collected at 5.00 atm and 500 o C. What is thevolume of nitrogen dioxide under standard conditions?If a sample of air occupies 2.00 L at STP, what is the volume at 75 o C and 365 torr?A sample of hydrogen fluoride gas has a volume of 1250 mL at STP. What is the pressure intorr if the volume is 255 mL at 300 o C?A sample of air occupies 0.750 L at standard conditions. What is the pressure in atm if thevolume is 100.0 mL at 25 o C?A sample of krypton gas has a volume of 500.0 mL at 225 mm Hg and -125 o C. Calculate thepressure in mm Hg if the gas occupies 220.0 mL at 100 o C.Page 8 of 11

Hoffman 2009 Chem- Gas lawsIdeal Gas Law PracticePV=nRTR=0.0821 atm*L/mol*KIf 5.00 mol of hydrogen gas occupies 50.0 mL at 25 o C, what is the pressure in atmospheres?If 1.25 mol of oxygen gas exerts a pressure of 1200 mm Hg at 25 o C, what is the volume inliters?If 10.0 L of nitrous oxide exerts a pressure of 125 psi at 373 K, what is the number of moles?If 0.100 mol of argon gas occupies 2.15 L at 725 torr, what is the temperature in degreesCelsius?A sample of unknown gas weighs 1.95 g and occupies 3.00 L at 1.25 atm and 20 o C. What isthe molar mass of the unknown gas?A sample of chlorine gas occupies 1550 mL at 0.945 atm and 50 o C. What is the mass of thesample?Page 9 of 11

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