CHEMISTRY 11 AP GAS LAW CALCULATIONS WORKSHEET

Transcription

1 CHEMISTRY 11 AP GAS LAW CALCULATIONS WORKSHEET 1) Consider the following identical containers each filled with 1 mole of helium gas. Container one is rigid and cannot expand. The piston in container two can rise or drop to allow free expansion or contraction of the gas volume. (ii) Density will increase since the same mass will occupy a smaller volume. (b) Another mole of gas is injected through a rubber portion of the piston? Be sure to support your answer with an explanation. Container 1: (i) Pressure will increase (double) due to a doubling of the number of moles of gas assuming no temperature change. (ii) Density will double since there are twice as many particles in the same volume. Container 2: (i) Pressure will remain constant as doubling n leads to doubling V assuming T remains constant. (ii) Density will not change since the volume will double to compensate for the increased number of particles. 2) Consider the flasks shown to the right each containing the same number of particles of the same gas at the same temperature. What simply gas law is depicted? How is the ratio of PV/nT held constant? Boyle s Law. n and T are held constant when V is decreased P is increased. What is the effect on the (i) pressure and (ii) density of each sample if: (a) The containers are dropped into an ice bath? Container 1: (i) The pressure will decrease due to the temperature decreasing (GayLussac s Law). (ii) The density remains the same since neither the mass nor the volume are changing. Container 2: (i) Volume will decrease due to the temperature decreasing (Charles s Law). Since both volume and temperature decrease the pressure will remain constant (Combined Gas Law).

2 3) Consider the flexible containers shown to the left each containing the same number of particles of the same gas at the same pressure. What simple gas is depicted? How is the ratio of PV/nT held constant? Charles s Law. P and n are held constant when T is increased V is increased. 4) Consider the container shown to the right under two different conditions. From condition one to two there are twice as many gas particles and the Kelvin temperature has been doubled. The volume remains constant. How is the ratio PV/nT maintained? As n is doubled and T is doubled and V is unchanged P must be quadrupled. It is increased due to the increased in both n and T. 5) Bobby collects a sample of gas from the exhaust pipe of his car. The sample contains 1.21 x molecules of gas at a pressure of 775 mm Hg and a temperature of 38 C. What is the volume of the gas sample? MOI 1 311k) ( 1.02am )V( 0.201mA )( Latmlmolk )( V 5.03L 6) A 44.8 L sample of gas weighs g at a temperature of 273 K and a pressure 0f torr. What is the molar mass of this gas? pvnrt ( )( 44.8L )n( Latmlmolk )( 273k ) n 2.00mA 128.2g.LK/O23Mdec0lesx/m0lO.201mol6.O22x/023mo1ecuksl.O2atmAtm775mmH9xy6OmmHgK38E+2730C31l0KPVnRT 2.00%164.ly/mo1

3 7) The propane tank by the science portable near the backfield of a typical school has a volume of 2210 L. Assuming the tank contains 3150 moles of propane gas what is the pressure inside the tank on a nice warm day of 28 C? K 28 C +273 C 301k PV NRT P( 2210L )( 3150mA )( Latmlmolk )( P kpa3s2atmx 35.2ohm 8) For an unknown gaseous element 3.23 g occupy 5.60 L at 153 C and kpa. (a) What is the molar mass of the element? K 153 C +273 C 301k ) youcanleaueatmasyourfinalunit Orconuertto Pa 350kPa kpa 426k PVnRT ( )( 5.60L )n( Latmlmolk )( 426k ) n 0.160mA 9 MOI 3.23g 0.160mg mg (b) How many atoms are contained in 3.23 g of this element? atoms atoms mg /0.ms/M0l2O.2g/molisdosesttoNe (c) What is the identity of the mysterious unknown element?

4 .. 9) At 46 C a sample of ammonia gas exerts a pressure of 4.8 atm. What is the pressure when the volume of the gas is reduced by 1/10 (0.10) of the original value when the temperature remains constant? Pitt.8atm Pa? Vi 1L V PVnRT constant 0.9L PN P2V2 ( 4.8atmKk)Pa( ) P2SBatm 10) A 1.45 L sample of radon gas is kept in a sealed radiationresistant container at 1.53 atm and 32 C. What will the pressure be if the temperature is lowered to C? P 1.53ohm Pa? Ti 32 C +273 C 305k Ta C k PVnRT Pg nfl constant f b5o3gkmagpy?q Pat48atm 11) A sample of polluted air is kept in a sealed container at 34.6 C and 31 psi. During winter the temperature decreased to C. At what temperature did the pressure in the container reach psi? 307.6k T2? F 34.6 C +273 C P 31psi D 26.75ps punrt constant gzsf F P 3301.Pg$k 2671ps Ta270K( 265.4k ) onlytothetens C C 270 since is significant place the answer of isroundedto 10 C

5 12) A sample of the gas bozone occupies a volume of 53.1 L at 52 C and 675 torr. What volume will this gas occupy at STP?? Vi 53.1L. V2 T T k P 67510N pa760torr PVnRT P nr constant D Pa ( K)(76Otorr)V2 325k k Va 39.6L