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1) Types of Variation2) Boyle's Law + PV Investigation 3) Charles' Law + TV Thought Lab4) Lussac's Law + TP Investigation5) The Combined Gas Law6) Avogadro and the Universal Gas Law Types of Variation
The Gas Laws
What type of variation is it?Write the equation of the line.
Boyle’s LawRobert Boyle (Irish Chemist, 16271691) studied pressure volume relationships.
Boyle’s Law – the volume of a given amount of gas, at a constant temperature, varies inversely with the applied pressure.
ASSUME: constant temp. and moles of gas.
V=k P
P=k V
According to Boyle's Law: if volume decreases to half, pressure increases by a factor of 2. if volume decreases to 1/3, pressure increases by a factor of 3.When volume of the container decreases, gas particles get closer together and exert more force on the walls of the container. (See fig. 11.14 on p. 432)When temp. and amount of gas is constant P1V1 = P2V2
Ex. p.434 #1A 50.0 cm3 sample of nitrogen gas is collected at 101.3 kPa. If the volume is reduced to 5.0 cm 3 , and the temperature remains constant, what will the final pressure of the nitrogen be? P1= 101.3 kPa V1= 50.0 cm 3
P2= ? V2= 5.0 cm3
P1V1 = P2V2
P2 = P1V1 V2 = (101.3 kPa)(50.0 cm 3) 5.0 cm 3
= 1.0 x 103 kPa
Homework p. 435 # 2, 3, (top) 2, 3, 4, 5, 6 (bottom)
p. 441 Charles' Law and Kelvin Temperatures Thought Lab
Temperature ( )
Volume ( )
400
300
Charles' Law Volume and Temperature of Gasses
Temperature273CVolum
e
Temperature is a measure of the average kinetic energy of the molecules in a substance.
What happens when we increase the temperature?http://phet.colorado.edu/en/simulation/gasproperties
French scientist Jaques Charles (17461823) was interested in hot air balloons and studied how an expandable container reacts to temperature changes. He found that if a gas was heated from 0 C to 273 C, it's volume would double. He also noticed that the x intercept on all of his graphs was 273 C.
In 1848 Lord Kelvin realized the significance of this finding.At 273 C
In real life gasses will condense and change state at temperatures close to 273 C.
Kelvin used Charles' finding as the basis of the Kelvin temperature scale.
TK = ___C + 273
Charles' Law
The volume of a fixed mass (or number of moles) of gas is proportional to its temperature if pressure is held constant (and temperature is in Kelvin).
Homeworkp.446 # 5a, 6a, 8,9
GayLussac's LawThe pressure of a fixed amount of gas, at constant volume, is directly proportional to it's Kelvin temperature.
P T
P = kT
P = kT
P1 = P2
T1 T2
p.447
Ex. p.450 # 14At 18C a sample of helium gas stored in a metal cylinder exerts a pressure of 17.5 atm. What will the pressure become if the temperature increases to 40C?
Gas LawsALWAYS SWITCHTO Kelvin
Try p. 449#13
(answer 18.8 atm)
Combined Gas LawBoyle's Law
Charles' Law
GayLussac's Law
Boyle's Law
Charles' Law
GayLussac's Law
Ex. p. 457#17A sample of gas has a volume of 150mL aat 260K and 92.3 kPa. What will the new volume be at 376K and 123 kPa?
Do p. 457 # 18-21(answers on p 469+523)
(answer 163mL)
Gasses HW List So FarBoylep.435 #2,3 (top) #2,3,4,5,6 (bottom)+Graphing Assignment Charlesp.446#5a,6a,8,9 + Thought LabGay-Lussacp.450#15 p.449#13 + GraphCombined p.457# 20,21 +18,19
p.446 #8A sample of nitrogen gas surrounding a circuit board occupies a volume of 300mL at 17C and 100 kPa. What volume will the nitrogen occupy at 100.0C if the pressure remains constant?
p.457#17A sample of gas has volume of 150 mL at 260K and 92.3 kPa. What will the new volume be at 376 K and 123 kPa.
GayLussac was confused by the volume of gas reactants and products in chemical reactions
2 volumes H2 + 1 volume O2 = 2 volumes H2O
3 volumes H2 + 1 volume N2 = 2 volumes NH3
1 volume H2 + 1 volume Cl2 = 2 volumes HCl
Avogadro recognized that these volume ratios were the same as the mole rations2 moles H2 + 1 moles O2 = 2 moles H2O3 moles H2 + 1 moles N2 = 2 moles NH3
1 moles H2 + 1 moles Cl2 = 2 moles HCl
Avagadro's Hypothesis
Avagadro proposed that equal volumes of ideal gasses at the same temperature and pressure contain the same number of moles of gas. (or the same number of molecules)This means that for a balanced chemical equation, the ratio of the volumes of the gasses equals the ratio of the moles of gasses. coefficients
At standard temperature and pressure (STP) a mole of gas occupies 22.4 L. The space occupied by 1 mole of gas is called the molar volume.T = 0 CP= 1 atm
T = 0C
P= 1 atm
Law of Combining VolumesIn a chemical reaction the ratio of the volumes of gas involved in the reaction equals the molar ration in the balanced chemical equation.
Ex. p.482#5A balloon contains 2.0 L of helium gas at STP. How many moles of helium are present? (0.089 mol)
p.482#6,7
Ideal Gas Law
Avagadro
Charles' Law
Boyle's Law
V= volumen = # molesT = temperatureP = pressureR= gas law constant
HOMEWORKp.487488 # 1214
HOMEWORKp.487488 # 1214
p.487 #12 4.00 L of ammonia gas is a container holds 2.17 mol at 206 kPa. What is the temperature in the container?
p.488 #13
p486 Sample Problem
A cylinder of laughing gas has diameter 23.0 cm and height 140 cm. THe pressure is 108 kPa and the temperature is 294 K. How many grams of laughing gas are in the cylinder?
4.00L of ammonia gas in a container holds 2.17mol at 206kPa. What is the temperature inside the container?
HOMEWORKp.487488 # 1214
How many kg of chlorine gas are contained in 87.6 m 3 at 290K and 2.4 atm?
p.488 # 13
BBT (2 min)http://www.youtube.com/watch?v=BVdy8HOhGWQ
Nova: Absolute Zero (1 hr 43 min)http://www.youtube.com/watch?v=y2jSv8PDDwA&feature=related
7:34 Boyle15:30 Temperature Pressure Experiments
Charles' Law Glove Experiment robertburkottawa (4 min)http://www.youtube.com/watch?v=IkRIKGN3i0k
Getting to Absolute Zero (11 min)Nobel prize in Physicshttp://www.youtube.com/watch?v=y7xp_hHbDUs