gases chapter 10/11 modern chemistry
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Gases Chapter 10/11 Modern Chemistry. Sections 10.1, 11.1-11.3 The Kinetic Molecular Theory of Matter Gases and Pressure The Gas Laws Gas Volumes and the Ideal Gas Law. Section 11.1. Gases and Pressure. Pressure. Pressure = force (in Newtons) per unit area - PowerPoint PPT PresentationTRANSCRIPT
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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GasesChapter 10/11Modern Chemistry
Sections 10.1, 11.1-11.3Sections 10.1, 11.1-11.3The Kinetic Molecular Theory of MatterThe Kinetic Molecular Theory of Matter
Gases and PressureGases and PressureThe Gas LawsThe Gas Laws
Gas Volumes and the Ideal Gas LawGas Volumes and the Ideal Gas Law
Chapter 11Section 1 Gases & Pressure p. 361-368
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Gases and Pressure
Section 11.1Section 11.1
Chapter 11Section 1 Gases & Pressure p. 361-368
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• Pressure = force (in Newtons) per unit area
• Pressure of a gas is caused by particles of a gas colliding with the walls of its container
• Pressure (P) of a gas depends on volume (V), temperature (T), and the number of particles (n).
PressurePressure
Chapter 11Section 1 Gases & Pressure p. 361-368
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Insert Holt Visualizing Matter Disc 2
Chapter 11Section 1 Gases & Pressure p. 361-368
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• The atmosphere exerts pressure.• 78% N, 21% O, 1% other• Atmospheric pressure is the sum of the
individual pressures of the gases.
Atomospheric PressureAtomospheric Pressure
Chapter 11Section 1 Gases & Pressure p. 361-368
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Measuring PressureMeasuring Pressure
p. 363
• Barometer: a device used to measure atmospheric pressure.
• Developed by Evangelista Torricelli in the early 1600s.
Chapter 11Section 1 Gases & Pressure p. 361-368
7p. 363Merc
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Chapter 11Section 1 Gases & Pressure p. 361-368
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Aneroid BarometerAneroid Barometer
The aneroid barometer is operated by a metal cell containing only a very small amount of air, or a series of such cells joined together. Increased air pressure causes the sides of the cell or cells to come closer together. One side is fixed to the base of the instrument while the other is connected by means of a system of levers and pulleys to a rotating pointer that moves over a scale on the face of the instrument.
Chapter 11Section 1 Gases & Pressure p. 361-368
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Measuring PressureMeasuring Pressure
• A manometer measures the pressure of a gas in a flask.
p. 363
Chapter 11Section 1 Gases & Pressure p. 361-368
10Manom
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Chapter 11Section 1 Gases & Pressure p. 361-368
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The average atmospheric pressure at sea level at 0°C.
•760 mm Hg – millimeters of mercury
•1.00 atm – atmospheres•101.325 kPa – kilopascals (SI Units)
1 pascal is the pressure exerted by a force of 1 Newton acting on an area of 1 square meter
See the table on page 364
Units of PressureUnits of Pressure
Chapter 11 Section 1 Gases & Pressure p. 361-368
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Table 1 Units of PressureTable 1 Units of Pressure
Chapter 11Section 1 Gases & Pressure p. 361-368
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• The average atmospheric pressure in Denver, Colorado, is 0.830 atm. Express this pressure in
(a) millimeters of mercury (mm Hg) and (b) kilopascals (kPa).
p. 3
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a. 631 mm Hg b. 84.1 kPa
Converting Pressure UnitsConverting Pressure Units
Chapter 11Section 1 Gases & Pressure p. 361-368
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1. Convert a pressure of 1.75 atm to kPa and to mm Hg.
2. The critical pressure of carbon dioxide is 72.7 atm. What is this value in units of pascals?
p. 3
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1.177 kPa, 1330 mm Hg
2. 7.37 106 Pa
Practice Problems p. 365Practice Problems p. 365
Chapter 11Section 1 Gases & Pressure p. 361-368
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• Partial Pressure: The pressure of each gas in a mixture
• Dalton’s Law of Partial Pressures: The total pressure of a gas mixture is the sum of the partial pressures of the component gases.
Dalton’s Law of Partial Dalton’s Law of Partial PressuresPressures
PT = p1 + p2 + p3 …
Chapter 11Section 1 Gases & Pressure p. 361-368
16Part
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Chapter 11Section 1 Gases & Pressure p. 361-368
17p. 363Law
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Chapter 11Section 1 Gases & Pressure p. 361-368
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Gases Collected by Water DisplacementGases Collected by Water Displacement
p. 366
Chapter 11Section 1 Gases & Pressure p. 361-368
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• A gas collected over water is a mixture of the gas and water vapor
• The pressure water exerts is called vapor pressure
Gases Collected by Water DisplacementGases Collected by Water Displacement
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Chapter 11Section 1 Gases & Pressure p. 361-368
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• When the water levels inside and outside the tube are the same the PT = Patm
Patm = pgas + pH2O
orpgas = Patm - pH2O
Gases Collected by Water DisplacementGases Collected by Water Displacement
PT>Patm
PT=Patm
PT<Patmatm
atm
atm
atm
Chapter 11Section 1 Gases & Pressure p. 361-368
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• The vapor pressure of water varies with temp.
Gases Collected by Water DisplacementGases Collected by Water Displacement
p. 8
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Chapter 11Section 1 Gases & Pressure p. 361-368
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• Oxygen gas from the decomposition of potassium chlorate, KClO3, was collected by water displacement. The barometric pressure and the temperature during the experiment were 731.0 mm Hg and 20.0°C, respectively. What was the partial pressure of the oxygen collected?
p. 3
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1. 713.5 mm Hg
Dalton’s Law ProblemsDalton’s Law Problems
Chapter 11Section 1 Gases & Pressure p. 361-368
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1. Some hydrogen gas is collected over water at 20.0°C.The levels of water inside and outside the gas-collection bottle are the same. The partial pressure of hydrogen is 742.5 mm Hg.What is the barometric pressure at the time the gas is collected?
p. 3
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1. 760.0 mm Hg
Practice Problems p. 367Practice Problems p. 367
Chapter 11 Section 2 The Gas Laws p. 369-377
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Boyle’s LawBoyle’s Law
Chapter 11 Section 2 The Gas Laws p. 369-377
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• P & V relationship; n & T held constant• “The volume of a fixed mass of gas
varies inversely with the pressure at constant temperature.”
Boyle’s LawBoyle’s Law
Insert Glencoe Chemistry Matter Disc 2
p. 369
Chapter 11 Section 2 The Gas Laws p. 369-377
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PV = kk is a constant
P1 V1 = k
P2 V2 = k
P1 V1 = P2 V2
Boyle’s LawBoyle’s Law
P1
P2
V1
V2
p. 370
Chapter 11 Section 2 The Gas Laws p. 369-377
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1. A sample of oxygen gas has a volume of 150.0 mL when its pressure is 0.947 atm. What will the volume of the gas be at a pressure of 0.987 atm if the temperature remains constant?
p. 3
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1. 144 mL O2
Boyle’s Law ProblemBoyle’s Law Problem
Chapter 11 Section 2 The Gas Laws p. 369-377
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Charles’ LawCharles’ Law
Chapter 11 Section 2 The Gas Laws p. 369-377
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• Same size degrees as the Celcius scale
• 0 K = -273.15° C
• 0 K = absolute zero
• K = 273 + °C
Kelvin Temperature ScaleKelvin Temperature Scale
Chapter 11 Section 2 The Gas Laws p. 369-377
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• V & T relationship; n & P held constant• The volume of a fixed mass of gas at
constant pressure varies directly with the Kelvin temperature.”
Charles’ LawCharles’ Law
Insert Glencoe Chemistry Matter Disc 2
Chapter 11 Section 2 The Gas Laws p. 369-377
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V / T = k k = a constant
V1 / T1 = k
V2 / T2 = k
V1 = V2
T1 = T2
Charles’ LawCharles’ Law
p. 372
T1 T2
V1
V2
Chapter 11 Section 2 The Gas Laws p. 369-377
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1. A sample of neon gas occupies a volume of 752 mL at 25°C. What volume will the gas occupy at 50°C if the pressure remains constant?
p. 3
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1. 815 mL Ne
Charles’ Law ProblemCharles’ Law Problem
Chapter 11 Section 2 The Gas Laws p. 369-377
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Combined Gas LawCombined Gas Law
Chapter 11 Section 2 The Gas Laws p. 369-377
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• P, V and T relationship; n held constant• “The combined gas law expresses the
relationship between pressure, volume and temperature of a fixed amount of gas.”
Combined Gas LawCombined Gas Law
Chapter 11 Section 2 The Gas Laws p. 369-377
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Standard Temperature and PressureStandard Pressure
1.00 atm760 mm Hg101.325 kPa
Standard Temperature273 K0° C
STPSTP
Chapter 11 Section 2 The Gas Laws p. 369-377
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1. A helium-filled balloon has a volume of 50.0 L at 25°C and 1.08 atm. What volume will it have at 0.855 atm and 10.0°C?
p. 3
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1. 60.0 L He
Combined Gas Law ProblemsCombined Gas Law Problems