# 2.1 MEASURING ATMOSPHERIC PRESSURE

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 12 CAPTER 2. ATMOSPERIC PRESSURE 2.1 MEASURING ATMOSPERIC PRESSURE The atmospheric pressure is the weiht exerted by the overhead atmosphere on a unit area of surface. It can be measured with a mercury barometer, consistin of a lon lass tube full of mercury inverted over a pool of mercury: vacuum A B h Fiure 2-1 Mercury barometer When the tube is inverted over the pool, mercury flows out of the tube, creatin a vacuum in the head space, and stabilies at an equilibrium heiht h over the surface of the pool. This equilibrium requires that the pressure exerted on the mercury at two points on the horiontal surface of the pool, A (inside the tube) and B (outside the tube), be equal. The pressure P A at point A is that of the mercury column overhead, while the pressure P B at point B is that of the atmosphere overhead. We obtain P A from measurement of h: P A ρ h (2.1) where ρ 13.6 cm -3 is the density of mercury and 9.8ms -2 is the acceleration of ravity. The mean value of h measured at sea level is 76.0 cm, and the correspondin atmospheric pressure is 1.013x10 5 k m -1 s -2 in SI units. The SI pressure unit is called the Pascal (Pa); 1 Pa 1 k m -1 s -2. Customary pressure units are the atmosphere (atm) (1 atm 1.013x10 5 Pa), the bar (b) (1 b 1x10 5 Pa), the millibar (mb) (1 mb 100 Pa), and the torr (1 torr 1 mm 134 Pa). The use of millibars is slowly ivin way to the equivalent SI unit of hectopascals (hpa). The mean atmospheric pressure at sea level is iven equivalently as P 1.013x10 5 Pa 1013 hpa 1013 mb 1 atm 760 torr.

2 MASS OF TE ATMOSPERE The lobal mean pressure at the surface of the Earth is P S 984 hpa, slihtly less than the mean sea-level pressure because of the elevation of land. We deduce the total mass of the atmosphere m a : m a 4πR 2 P S 5.2x10 18 k (2.2) where R 6400 km is the radius of the Earth. The total number of moles of air in the atmosphere is N a m a /M a 1.8x10 20 moles. Exercise 2-1. Atmospheric CO 2 concentrations have increased from 280 ppmv in preindustrial times to 365 ppmv today. What is the correspondin increase in the mass of atmospheric carbon? Assume CO 2 to be well mixed in the atmosphere. Answer. We need to relate the mixin ratio of CO 2 to the correspondin mass of carbon in the atmosphere. We use the definition of the mixin ratio from equation (1.3), C CO2 n CO2 n a N C N a M a M C m C m a where N C and N a are the total number of moles of carbon (as CO 2 ) and air in the atmosphere, and m C and m a are the correspondin total atmospheric masses. The second equality reflects the assumption that the CO 2 mixin ratio is uniform throuhout the atmosphere, and the third equality reflects the relationship N m/m. The chane m C in the mass of carbon in the atmosphere since preindustrial times can then be related to the chane C CO2 in the mixin ratio of CO 2. Aain, always use SI units when doin numerical calculations (this is your last reminder!): m C M C m a C CO2 5.2x10 M a x10 ( 280x10 6 ) x x x10 14 k 180 billion tons!

3 VERTICAL PROFILES OF PRESSURE AND TEMPERATURE Fiure 2-2 shows typical vertical profiles of pressure and temperature observed in the atmosphere. Pressure decreases exponentially with altitude. The fraction of total atmospheric weiht located above altitude is P()/P(0). At 80 km altitude the atmospheric pressure is down to 0.01 hpa, meanin that % of the atmosphere is below that altitude. You see that the atmosphere is of relatively thin vertical extent. Astronomer Fred oyle once said, "Outer space is not far at all; it's only one hour away by car if your car could o straiht up!" Mesosphere Altitude, km Stratosphere Troposphere Pressure, hpa Temperature, K Fiure 2-2 Mean pressure and temperature vs. altitude at 30 o N, March Atmospheric scientists partition the atmosphere vertically into domains separated by reversals of the temperature radient, as shown in Fiure 2-2. The troposphere extends from the surface to 8-18 km altitude dependin on latitude and season. It is characteried by a decrease of temperature with altitude which can be explained simply thouh not quite correctly by solar heatin of the surface (we will come back to this issue in chapters 4 and 7). The stratosphere extends from the top of the troposphere (the tropopause) to about 50 km altitude (the stratopause) and is characteried by an increase of temperature with altitude due to absorption of solar radiation by the oone layer (problem 1. 3). In

4 15 the mesosphere, above the oone layer, the temperature decreases aain with altitude. The mesosphere extends up to 80 km (mesopause) above which lies the thermosphere where temperatures increase aain with altitude due to absorption of stron UV solar radiation by N 2 and O 2. The troposphere and stratosphere account toether for 99.9% of total atmospheric mass and are the domains of main interest from an environmental perspective. Exercise 2-2 What fraction of total atmospheric mass at 30 o N is in the troposphere? in the stratosphere? Use the data from Fiure 2-2. Answer. The troposphere contains all of atmospheric mass except for the fraction P(tropopause)/P(surface) that lies above the tropopause. From Fiure 2-2 we read P(tropopause) 100 hpa, P(surface) 1000 hpa. The fraction F trop of total atmospheric mass in the troposphere is thus P( tropopause) F trop P( 0) The troposphere accounts for 90% of total atmospheric mass at 30 o N (85% lobally). The fraction F strat of total atmospheric mass in the stratosphere is iven by the fraction above the tropopause, P(tropopause)/P(surface), minus the fraction above the stratopause, P(stratopause)/P(surface). From Fiure 2-2 we read P(stratopause) 0.9 hpa, so that P( tropopause) P( stratopause) F strat P( surface) The stratosphere thus contains almost all the atmospheric mass above the troposphere. The mesosphere contains only about 0.1% of total atmospheric mass. 2.4 BAROMETRIC LAW We will examine the factors controllin the vertical profile of atmospheric temperature in chapters 4 and 7. We focus here on explainin the vertical profile of pressure. Consider an elementary slab of atmosphere (thickness d, horiontal area A) at altitude :

5 16 horiontal area A pressure-radient force (P()-P(+d))A +d weiht ρ a Ad Fiure 2-3 Vertical forces actin on an elementary slab of atmosphere The atmosphere exerts an upward pressure force P()A on the bottom of the slab and a downward pressure force P(+d)A on the top of the slab; the net force, (P()-P(+d))A, is called the pressure-radient force. Since P() > P(+d), the pressure-radient force is directed upwards. For the slab to be in equilibrium, its weiht must balance the pressure-radient force: ρ a Ad ( P( ) P ( + d) )A (2.3) Rearranin yields P ( + d) P ( ) ρ d a (2.4) The left hand side is dp/d by definition. Therefore dp ρ d a (2.5) Now, from the ideal as law, ρ a PM a RT (2.6) where M a is the molecular weiht of air and T is the temperature. Substitutin (2.6) into (2.5) yields: dp P M a d RT (2.7) We now make the simplifyin assumption that T is constant with

6 17 altitude; as shown in Fiure 2-2, T varies by only 20% below 80 km. We then interate (2.7) to obtain lnp ( ) lnp( 0) M a RT (2.8) which is equivalent to M a P ( ) P( 0) exp RT (2.9) Equation (2.9) is called the barometric law. It is convenient to define a scale heiht for the atmosphere: RT M a (2.10) leadin to a compact form of the Barometric Law: P ( ) P( 0)e ---- (2.11) For a mean atmospheric temperature T 250 K the scale heiht is 7.4 km. The barometric law explains the observed exponential dependence of P on in Fiure 2-2; from equation (2.11), a plot of vs. ln P yields a straiht line with slope - (check out that the slope in Fiure 2-2 is indeed close to -7.4 km). The small fluctuations in slope in Fiure 2-2 are caused by variations of temperature with altitude which we nelected in our derivation. The vertical dependence of the air density can be similarly formulated. From (2.6), ρ a and P are linearly related if T is assumed constant, so that ρ a ( ) ρ a ( 0)e ---- (2.12) A similar equation applies to the air number density n a. For every rise in altitude, the pressure and density of air drop by a factor e 2.7; thus provides a convenient measure of the thickness of the atmosphere. In calculatin the scale heiht from (2.10) we assumed that air

7 18 behaves as a homoeneous as of molecular weiht M a 29 mol -1. Dalton s law stipulates that each component of the air mixture must behave as if it were alone in the atmosphere. One miht then expect different components to have different scale heihts determined by their molecular weiht. In particular, considerin the difference in molecular weiht between N 2 and O 2, one miht expect the O 2 mixin ratio to decrease with altitude. owever, ravitational separation of the air mixture takes place by molecular diffusion, which is considerably slower than turbulent vertical mixin of air for altitudes below 100 km (problem 4. 9). Turbulent mixin thus maintains a homoeneous lower atmosphere. Only above 100 km does sinificant ravitational separation of ases bein to take place, with lihter ases bein enriched at hiher altitudes. Durin the debate over the harmful effects of chlorofluorocarbons (CFCs) on stratospheric oone, some not-so-reputable scientists claimed that CFCs could not possibly reach the stratosphere because of their hih molecular weihts and hence low scale heihts. In reality, turbulent mixin of air ensures that CFC mixin ratios in air enterin the stratosphere are essentially the same as those in surface air. Exercise 2-3 The cruisin altitudes of subsonic and supersonic aircraft are 12 km and 20 km respectively. What is the relative difference in air density between these two altitudes? Answer. Apply (2.12) with 1 12 km, 2 20 km, 7.4 km: ( 2 1 ) ρ( 2 ) e ρ( 1 ) e e The air density at 20 km is only a third of that at 12 km. The hih speed of supersonic aircraft is made possible by the reduced air resistance at 20 km. 2.5 TE SEA-BREEZE CIRCULATION An illustration of the Barometric Law is the sea-breee circulation commonly observed at the beach on summer days (Fiure 2-4). Consider a coastline with initially the same atmospheric temperatures and pressures over land (L) and over sea (S). Assume that there is initially no wind. In summer durin the day the land

8 19 surface is heated to a hiher temperature than the sea. This difference is due in part to the larer heat capacity of the sea, and in part to the consumption of heat by evaporation of water. (a) Initial state: equal T, P over land and sea (T L T S, P L P S ) slope - S L LAND SEA ln P (b) Sunny day: land heats more than sea (T L > T S ) L > S P L () > P S () hih-altitude flow from land to sea Flow S L LAND SEA ln P (c) ih-altitude flow from land to sea P L (0) < P S (0) reverse surface flow from sea to land L S Circulation cell LAND SEA ln P Fiure 2-4 The sea-breee circulation As lon as there is no flow of air between land and sea, the total air columns over each reion remain the same so that at the surface P L (0) P S (0). owever, the hiher temperature over land results in

9 20 a larer atmospheric scale heiht over land ( L > S ), so that above the surface P L () > P S () (Fiure 2-4). This pressure difference causes the air to flow from land to sea, decreasin the mass of the air column over the land; consequently, at the surface, P L (0) < P S (0) and the wind blows from sea to land (the familiar "sea breee"). Compensatin vertical motions result in the circulation cell shown in Fiure 2-4. This cell typically extends ~10 km horiontally across the coastline and ~1 km vertically. At niht a reverse circulation is frequently observed (the land breee) as the land cools faster than the sea.

### Lecture 3. Science A February 2008 Finish discussion of the perfect gas law from Lecture Review pressure concepts: weight of overlying

Lecture 3. Science A-30 07 February 2008 Finish discussion of the perfect gas law from Lecture 2. 1. Review pressure concepts: weight of overlying fluid ("hydrostatic"), force of molecules bouncing off

### air water Road map to EPS 5 Lectures5: Pressure, barometric law, buoyancy fluid moves

Road map to EPS 5 Lectures5: Pressure, barometric law, buoyancy water air fluid moves Fig. 7.6: Pressure in the atmosphere (compressible) and ocean (incompressible). Lecture 5. EPS 5: 08 February 2010

### Pressure of the atmosphere varies with elevation and weather conditions. Barometer- device used to measure atmospheric pressure.

Chapter 12 Section 1 Pressure A gas exerts pressure on its surroundings. Blow up a balloon. The gas we are most familiar with is the atmosphere, a mixture of mostly elemental nitrogen and oxygen. Pressure

### IV. Intersection: what we know, would like to know, will never know, and what can we contribute to the debate. air water

IV. Intersection: what we know, would like to know, will never know, and what can we contribute to the debate. III. Atmospheric & Ocean Biogeochemistry: Second element of climate and environmental science

### Chapter 1 The Atmosphere

Chapter 1 The Atmosphere Section 1 - Guiding Questions How is the atmosphere important to living things? What gases are present in Earth s atmosphere? Section 1 - The Air Around You Importance of the Atmosphere

### Gases and Pressure. Main Ideas

Gases and Pressure Key Terms pressure millimeters of mercury partial pressure newton atmosphere of pressure Dalton s law of partial pressures barometer pascal In the chapter States of Matter, you read

### Gases and Pressure SECTION 11.1

SECTION 11.1 Gases and In the chapter States of Matter, you read about the kineticmolecular theory of matter. You were also introduced to how this theory explains some of the properties of ideal gases.

### Variation of Pressure with Depth in a Fluid *

OpenStax-CNX module: m42192 1 Variation of Pressure with Depth in a Fluid * OpenStax This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 3.0 Abstract Dene

### Chapter 7 Weather and Climate

Chapter 7 Weather and Climate *Describe what weather is, what affects it, and where it occurs. *Explain the connection between air pressure and wind. * *Many factors affect a region s weather. * *atmosphere

### Chapter 5. Nov 6 1:02 PM

Chapter 5 Nov 6 1:02 PM Expand to fill their containers Fluid motion (they flow) Have low densities (1/1000 the density of equivalent liquids or solids) Compressible Can Effuse and Diffuse Effuse: The

### Kinetic-Molecular Theory

GASES Chapter Eleven Kinetic-Molecular Theory! Recall that our only previous description of gases stated that gases completely fill and take the shape of their containers.! The Kinetic-Molecular Theory

### Chapter 12. Properties of Gases

Properties of Gases Each state of matter has its own properties. Gases have unique properties because the distance between the particles of a gas is much greater than the distance between the particles

### Pressure and buoyancy in fluids

Pressure and buoyancy in fluids FCQ s for lecture and tutorials will be next week. Buoyancy force today Fluid dynamics on Monday (alon with the loudest demonstration of the semester). Review on Wednesday

### I. Atmosphere. Maintains a balance between the amount of heat absorbed from the Sun and the amount of heat that escapes back into space.

Earth s Atmosphere 1-1 I Objectives: Identify the gases in Earthś atmosphere Describe the structures of Earthś atmosphere. Explain what causes air pressure. I. Atmosphere Maintains a balance between the

### CP Chapter 13/14 Notes The Property of Gases Kinetic Molecular Theory

CP Chapter 13/14 Notes The Property of Gases Kinetic Molecular Theory Kinetic Molecular Theory of Gases The word kinetic refers to. Kinetic energy is the an object has because of its motion. Kinetic Molecular

### Chapter 5: Gases 5.1 Pressure Why study gases? An understanding of real world phenomena. An understanding of how science works.

Chapter 5: Gases 5.1 Pressure Why study gases? An understanding of real world phenomena. An understanding of how science works. A Gas Uniformly fills any container. Easily compressed. Mixes completely

### Gas Pressure. Pressure is the force exerted per unit area by gas molecules as they strike the surfaces around them.

Chapter 5 Gases Gas Gases are composed of particles that are moving around very fast in their container(s). These particles moves in straight lines until they collides with either the container wall or

### Chem 110 General Principles of Chemistry

CHEM110 Worksheet - Gases Chem 110 General Principles of Chemistry Chapter 9 Gases (pages 337-373) In this chapter we - first contrast gases with liquids and solids and then discuss gas pressure. - review

### Background physics concepts (again)

Background physics concepts (again) position coordinate for location, say x (1-D) velocity changing position over time (magnitude and ) acceleration changing velocity v = x t = x 2 x 1 t 2 t 1 a = v t

### ρ B ρ A Physics: Principles and Applications, 6e Giancoli Chapter 10 Fluids = m B V B m A = m A V A = ρ A = ρ B m B Answer B = 4 3

Physics: Principles and Applications, 6e Giancoli Chapter 10 Fluids Conceptual Questions 1) The three common phases of matter are A) solid, liquid, and as. B) solid, liquid, and vapor. C) solid, plasma,

### Lecture Presentation. Chapter 10. Gases. John D. Bookstaver St. Charles Community College Cottleville, MO Pearson Education, Inc.

Lecture Presentation Chapter 10 John D. Bookstaver St. Charles Community College Cottleville, MO Characteristics of Unlike liquids and solids, gases Expand to fill their containers. Are highly compressible.

### Chapter 13 Fluids. Copyright 2009 Pearson Education, Inc.

Chapter 13 Fluids Phases of Matter Density and Specific Gravity Pressure in Fluids Atmospheric Pressure and Gauge Pressure Pascal s Principle Units of Chapter 13 Measurement of Pressure; Gauges and the

### C h e m i s t r y 1 A : C h a p t e r 5 P a g e 1

C h e m i s t r y 1 A : C h a p t e r 5 P a g e 1 Chapter 5: Gases Homework: Read Chapter 5. Work out sample/practice exercises Keep up with MasteringChemistry assignments Gas Properties: Ideal Gas: Gases

### Chapter 10: Gases. Characteristics of Gases

Chapter 10: Gases Learning Outcomes: Calculate pressure and convert between pressure units with an emphasis on torr and atmospheres. Calculate P, V, n, or T using the ideal-gas equation. Explain how the

### Kinetic Molecular Theory imaginary Assumptions of Kinetic Molecular Theory: Problems with KMT:

AP Chemistry Ms. Ye Name Date Block Kinetic Molecular Theory Explains properties of gases, liquids, and solids in terms of energy using an ideal gas, an imaginary which fits all the assumptions of kinetic

### Chapter 10 Gases. Characteristics of Gases. Pressure. The Gas Laws. The Ideal-Gas Equation. Applications of the Ideal-Gas Equation

Characteristics of Gases Chapter 10 Gases Pressure The Gas Laws The Ideal-Gas Equation Applications of the Ideal-Gas Equation Gas mixtures and partial pressures Kinetic-Molecular Theory Real Gases: Deviations

### Chapter 13 Gases and Pressure. Pressure and Force. Pressure is the force per unit area on a surface. Force Area. Pressure =

Chapter 13 Gas Laws Chapter 13 Gases and Pressure Pressure and Force Pressure is the force per unit area on a surface. Pressure = Force Area Chapter 13 Gases and Pressure Gases in the Atmosphere The atmosphere

### The Kinetic-Molecular Theory of Gases based on the idea that particles are always in motion

The Kinetic-Molecular Theory of Gases based on the idea that particles are always in motion Five assumptions: 1. Most of the volume occupied dby a gas is empty space 2. Collisions between gas particles

### Earth and Planetary Sciences 5 Midterm Exam March 10, 2010

Earth and Planetary Sciences 5 Midterm Exam March 10, 2010 Name: Teaching Fellow: INSTRUCTIONS PUT YOUR NAME ON EACH PAGE. The exam will last 80 minutes. Complete the problems directly on the exam. Extra

### Earth s Atmosphere. Earth s atmosphere is a key factor in allowing life to survive here.

Chapter 10.2 Earth s Atmosphere Earth s atmosphere is a key factor in allowing life to survive here. This narrow band of air has the right ingredients and maintains the correct temperature, to allow life

### Section 8: Gases. The following maps the videos in this section to the Texas Essential Knowledge and Skills for Science TAC (c).

Section 8: Gases The following maps the videos in this section to the Texas Essential Knowledge and Skills for Science TAC 112.35(c). 8.01 Simple Gas Laws Chemistry (9)(A) 8.02 Ideal Gas Law Chemistry

### Unit 9 Packet: Gas Laws Introduction to Gas Laws Notes:

Name: Unit 9 Packet: Gas Laws Introduction to Gas Laws Notes: Block: In chemistry, the relationships between gas physical properties are described as gas laws. Some of these properties are pressure, volume,

### PHYS 101 Previous Exam Problems

PHYS 101 Previous Exam Problems CHAPTER 14 Fluids Fluids at rest pressure vs. depth Pascal s principle Archimedes s principle Buoynat forces Fluids in motion: Continuity & Bernoulli equations 1. How deep

### 8. Now plot on the following grid the values of T (K) and V from the table above, and connect the points.

Charles s Law According to Charles s law, the volume of a fixed mass of gas varies directly with its Kelvin temperature if its pressure is constant. The following table contains Celsius temperature and

### Fluid Mechanics. Liquids and gases have the ability to flow They are called fluids There are a variety of LAWS that fluids obey

Fluid Mechanics Fluid Mechanics Liquids and gases have the ability to flow They are called fluids There are a variety of LAWS that fluids obey Density Regardless of form (solid, liquid, gas) we can define

Chapter 13 Gases Copyright Cengage Learning. All rights reserved 1 Section 13.1 Pressure Why study gases? An understanding of real world phenomena. An understanding of how science works. Copyright Cengage

### You should be able to: Describe Equipment Barometer Manometer. 5.1 Pressure Read and outline 5.1 Define Barometer

A P CHEMISTRY - Unit 5: Gases Unit 5: Gases Gases are distinguished from other forms of matter, not only by their power of indefinite expansion so as to fill any vessel, however large, and by the great

### Chapter 5. Pressure. Atmospheric Pressure. Gases. Force Pressure = Area

Chapter 5 Gases Water for many homes is supplied by a well The pump removes air from the pipe, decreasing the air pressure in the pipe The pressure then pushes the water up the pipe Pressure Atmospheric

### Chapter 9 Fluids and Buoyant Force

Chapter 9 Fluids and Buoyant Force In Physics, liquids and gases are collectively called fluids. 3/0/018 8:56 AM 1 Fluids and Buoyant Force Formula for Mass Density density mass volume m V water 1000 kg

### CHAPTER 1 KINETIC THEORY OF GASES (PART A)

For updated version, please click on http://ocw.ump.edu.my BSK1133 PHYSICAL CHEMISTRY CHAPTER 1 KINETIC THEORY OF GASES (PART A) PREPARED BY: DR. YUEN MEI LIAN AND DR. SITI NOOR HIDAYAH MUSTAPHA Faculty

### Chapter 13: The Behavior of Gases

Chapter 13: The Behavior of Gases I. First Concepts a. The 3 states of matter most important to us: solids, liquids, and gases. b. Real Gases and Ideal Gases i. Real gases exist, ideal gases do not ii.

### CP Chapter 13/14 Notes The Property of Gases Kinetic Molecular Theory

CP Chapter 13/14 Notes The Property of Gases Kinetic Molecular Theory Kinetic Molecular Theory of Gases The word kinetic refers to. Kinetic energy is the an object has because of its motion. Kinetic Molecular

### 4.) There are no forces of attraction or repulsion between gas particles. This means that

KINETIC MOLECULAR (K-M) THEORY OF MATTER NOTES - based on the idea that particles of matter are always in motion - assumptions of the K-M Theory 1.) Gases consist of large numbers of tiny particles that

### Chapter 13 Fluids. Copyright 2009 Pearson Education, Inc.

Chapter 13 Fluids Phases of Matter Density and Specific Gravity Pressure in Fluids Atmospheric Pressure and Gauge Pressure Pascal s Principle Units of Chapter 13 Measurement of Pressure; Gauges and the

### Chapter 13. liquids. gases. 1) Fluids exert pressure. a) because they're made up of matter and therefore forces are applied to them

\ Chapter 13 Fluids 1) Fluids exert pressure a) because they're made up of matter and therefore forces are applied to them liquids gases b) they are made of matter in constant motion colliding with other

### Section 5.1 Pressure. Why study gases? An understanding of real world phenomena. An understanding of how science works.

Chapter 5 Gases Section 5.1 Pressure Why study gases? An understanding of real world phenomena. An understanding of how science works. Copyright Cengage Learning. All rights reserved 2 Section 5.1 Pressure

Hydrostatic pressure Consider a tank of fluid which contains a very thin plate of (neutrally buoyant) material with area A. This situation is shown in Figure below. If the plate is in equilibrium (it does

### Gas Laws. Directions: Describe what contribution each of the Scientist below made to the Gas Laws and include there gas law equation.

Gas Laws Name Date Block Introduction One of the most amazing things about gases is that, despite wide differences in chemical properties, all the gases more or less obey the gas laws. The gas laws deal

### Example: 25 C = ( ) K = 298 K. Pressure Symbol: p Units: force per area 1Pa (Pascal) = 1 N/m 2

Chapter 6: Gases 6.1 Measurements on Gases MH5, Chapter 5.1 Let s look at a certain amount of gas, i.e. trapped inside a balloon. To completely describe the state of this gas one has to specify the following

### Lake Effect Snow Storms METR 4433, Mesoscale Meteorology Spring 2006 (some of the material in this section came from Bart Geerts)

Lake Effect Snow Storms METR 4433, Mesoscale Meteoroloy Sprin 2006 (some of the material in this section came from Bart Geerts) 1 Definition: The term lake effect enerally refers to the effect of any lake

### Unit A-2: List of Subjects

ES312 Energy Transfer Fundamentals Unit A: Fundamental Concepts ROAD MAP... A-1: Introduction to Thermodynamics A-2: Engineering Properties Unit A-2: List of Subjects Basic Properties and Temperature Pressure

### Gilbert Kirss Foster. Chapter 10. Properties of Gases The Air We Breathe

Gilbert Kirss Foster Chapter 10 Properties of Gases The Air We Breathe Chapter Outline 10.1 The Properties of Gases 10.2 Effusion and the Kinetic Molecular Theory of Gases 10.3 Atmospheric Pressure 10.4

### CHEMISTRY - CLUTCH CH.5 - GASES.

!! www.clutchprep.com CONCEPT: UNITS OF PRESSURE Pressure is defined as the force exerted per unit of surface area. Pressure = Force Area The SI unit for Pressure is the, which has the units of. The SI

### PURE SUBSTANCE. Nitrogen and gaseous air are pure substances.

CLASS Third Units PURE SUBSTANCE Pure substance: A substance that has a fixed chemical composition throughout. Air is a mixture of several gases, but it is considered to be a pure substance. Nitrogen and

### Chemistry Chapter 12. Characteristics of Gases. Characteristics of Gases 1/31/2012. Gases and Liquids

Importance of Gases Chemistry Chapter 12 Gases and Liquids Airbags fill with N 2 gas in an accident. Gas is generated by the decomposition of sodium azide, NaN 3. 2 NaN 3 ---> 2 Na + 3 N 2 THREE STATES

### Lecture 19 Fluids: density, pressure, Pascal s principle and Buoyancy.

Lecture 19 Water tower Fluids: density, pressure, Pascal s principle and Buoyancy. Hydraulic press Pascal s vases Barometer What is a fluid? Fluids are substances that flow. substances that take the shape

### GEOG112 - Assignment 2. Site A Site B Site C Temp ( C) Altitude (km) Temp ( C)

GEOG112 - Assignment 2 Name Spring 2019 18 pts possible Site A Site B Site C Temp ( C) Altitude (km) Temp ( C) Altitude (km) Temp ( C) Altitude (km) 24 0 30 0 15 0 10 1 18 1 4 1 14 2 14 2-3 2 9 3 8 3-7

### Gases. Chapter 9. Introduction. Chapter Outline

Chapter 9 Gases 461 Chapter 9 Gases Figure 9.1 The hot air inside these balloons is less dense than the surrounding cool air. This results in a buoyant force that causes the balloons to rise when their

### Gases. Chapter 5: Gas Laws Demonstration. September 10, Chapter 5 Gasses.notebook. Dec 18 10:23 AM. Jan 1 4:11 PM. Crushing 55 gallon drum

Chapter 5: Gases Dec 18 10:23 AM Gas Laws Demonstration Crushing 55 gallon drum Egg in a bottle Student in a bag Boiling Water Charles gas Law Water in a flask Ballon in a bottle Jan 1 4:11 PM 1 5.1 Pressure

### 3 1 PRESSURE. This is illustrated in Fig. 3 3.

P = 3 psi 66 FLUID MECHANICS 150 pounds A feet = 50 in P = 6 psi P = s W 150 lbf n = = 50 in = 3 psi A feet FIGURE 3 1 The normal stress (or pressure ) on the feet of a chubby person is much greater than

### End of Chapter Exercises

End of Chapter Exercises Exercises 1 12 are conceptual questions that are designed to see if you have understood the main concepts of the chapter. 1. While on an airplane, you take a drink from your water

### 2. Calculate the ratio of diffusion rates for carbon monoxide (CO) and carbon dioxide (CO2). υa = MB = 44 = 1.25

Gas laws worksheet (2-08) (modified 3/17) Answer key Graham s Law 1. Calculate the ratio of effusion rates for nitrogen (N2) and neon (Ne). υa = MB = 20 = 0.845 υb MA 28 2. Calculate the ratio of diffusion

### Earth s Atmosphere. Atmospheric Gases. Other Gases. Solids in the Atmosphere

Earth s Atmosphere 1-1 I Atmospheric Gases Earth s Atmosphere extends from earth s surface to outer space. It is made up of a mixture of gases with some solids and liquids. Other Gases Water Vapor in the

### Chapter 9 Gases: Their Properties and Behavior

Chapter 9 Gases: Their Properties and Behavior 國防醫學院生化學科王明芳老師 2011-11-15 & 2011-11-22 Chapter 9/1 Gases and Gas Pressure Gas mixtures are homogeneous and compressible. Air-the mixture of gases. Molecular

### Unit 7. Pressure in fluids

-- Unit 7. Pressure in fluids Index 1.- Pressure...2 2.- Fluids...2 3.- Pressure in fluids...3 4.- Pascal's principle...5 5.- Archimedes principle...6 6.- Atmospheric pressure...7 6.1.- Torricelli and

### Air Pressure and Wind. Goal: Explain the formation of wind based on differences in air pressure

Air Pressure and Wind Goal: Explain the formation of wind based on differences in air pressure What is Air Pressure? Reminder: Air pressure is thickest near Earth s surface and becomes thinner as we move

Chemistry A Molecular Approach Fourth Edition Chapter 5 Gases Supersonic Skydiving and the Risk of Decompression Gas Gases are composed of particles that are moving around very fast in their container(s).

### Name Period Date. Lab 5: The Molar Volume of a Gas

Name Period Date Lab 5: The Molar Volume of a Gas Objective: To determine the actual molar volume of oxyen as To determine an experimental value for the universal as constant Introduction To calculate

### Example: Calculate the density of methane at 50 psig and 32 ⁰F. H.W. In previous example calculate the density of methane in gm/m 3.

Gas density Because the density of a substance is defined as mass per unit volume, the density of gas (ρ g ), at given temperature and pressure can be derived as follows: If P in psia, T in ⁰R and R =

### Worksheet 1.7: Gas Laws. Charles Law. Guy-Lassac's Law. Standard Conditions. Abbreviations. Conversions. Gas Law s Equation Symbols

Name Block Worksheet 1.7: Gas Laws Boyle s Law Charles Law Guy-Lassac's Law Combined Gas Law For a given mass of gas at constant temperature, the volume of a gas varies inversely with pressure PV = k The

### Questions. theonlinephysicstutor.com. facebook.com/theonlinephysicstutor. Name: Edexcel Drag Viscosity. Questions. Date: Time: Total marks available:

Name: Edexcel Drag Viscosity Questions Date: Time: Total marks available: Total marks achieved: Questions Q1. A small helium balloon is released into the air. The balloon initially accelerates upwards.

### L 13 Fluid Statics [2] More on fluids. How can a steel boat float. A ship can float in a cup of water! Today s weather

L 13 Fluid Statics [2] More on fluids. How can a steel boat float. A ship can float in a cup of water! Today s weather The deeper you go the higher the pressure P Top A hypothetical volume of water inside

### Chemistry 20 Unit 2 Gases FITB Notes. Topic A Characteristics of Gases

Chemistry 20 Unit 2 Gases FITB Notes General Outcome: Topic A Characteristics of Gases We use technologies that were designed with the knowledge of the visible characteristics ( ) of gases ex. SCUBA equipment,

### CHM Basics of Gases (r14) Charles Taylor 1/9

CHM 110 - Basics of Gases (r14)- 2014 Charles Taylor 1/9 Introduction The gas phase is noticeably different from the other two phases of matter. Here are some of the more obvious differences. Gases are

### 1. All fluids are: A. gases B. liquids C. gases or liquids D. non-metallic E. transparent ans: C

Chapter 14: FLUIDS 1 All fluids are: A gases B liquids C gases or liquids D non-metallic E transparent 2 Gases may be distinguished from other forms of matter by their: A lack of color B small atomic weights

### Chapter 3: Atmospheric pressure and temperature

Chapter 3: Atmospheric pressure and temperature 3.1 Distribution of pressure with altitude The barometric law Atmospheric pressure declines with altitude, a fact familiar to everyone who has flown in an

### PHY131H1S - Class 23. Today: Fluids Pressure Pascal s Law Gauge Pressure Buoyancy, Archimedes Principle. A little pre-class reading quiz

PHY131H1S - Class 23 Today: Fluids Pressure Pascal s Law Gauge Pressure Buoyancy, Archimedes Principle Archimedes (287-212 BC) was asked to check the amount of silver alloy in the king s crown. The answer

### Chapter 10. Physical Characteristics of Gases

Chapter 10 Physical Characteristics of Gases Kinetic Molecular Theory An understanding of the behavior of atoms that make up matter Ideal gas: an imaginary gas that perfectly fits all assumptions of the

### PHSC 3033: Meteorology Stability

PHSC 3033: Meteorology Stability Equilibrium and Stability Equilibrium s 2 States: Stable Unstable Perturbed from its initial state, an object can either tend to return to equilibrium (A. stable) or deviate

### End of Chapter Exercises

End of Chapter Exercises Exercises 1 12 are conceptual questions that are designed to see if you have understood the main concepts of the chapter. 1. While on an airplane, you take a drink from your water

### kpa := 1000 Pa p atm := 101 kpa := i is inside o is outside effects are small. R gas := M gas 1000 mol

Homework Problem 1 Tall buildings can develop a significant difference in pressure between the inside and the outside of the build lock entrances are used at the ground level so the pressure at the ground

### Lecture Outline Chapter 15. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.

Lecture Outline Chapter 15 Physics, 4 th Edition James S. Walker Chapter 15 Fluids Density Units of Chapter 15 Pressure Static Equilibrium in Fluids: Pressure and Depth Archimedes Principle and Buoyancy

### Unit 8: Gases and States of Matter

Unit 8: Gases and States of Matter Gases Particles that have no definite shape or volume. They adapt to the shape and volume of their container. Ideal gases are imaginary gases that comply with all the

### Chemistry HP Unit 6 Gases. Learning Targets (Your exam at the end of Unit 6 will assess the following:) 6. Gases

Chemistry HP Unit 6 Gases Learning Targets (Your exam at the end of Unit 6 will assess the following:) 6. Gases 6-1. Define pressure using a mathematical equation. 6-2. Perform calculations involving pressure,

### Chapter 15 Fluid. Density

Density Chapter 15 Fluid Pressure Static Equilibrium in Fluids: Pressure and Depth Archimedes Principle and Buoyancy Applications of Archimedes Principle By Dr. Weining man 1 Units of Chapter 15 Fluid

### Notes: Gas Laws (text Ch. 11)

Name Per. Notes: Gas Laws (text Ch. 11) NOTE: This set of class notes is not complete. We will be filling in information in class. If you are absent, it is your responsibility to get missing information

### 1. [Chang7 5.P.013.] Convert 295 mmhg to kpa. kpa Convert 2.0 kpa to mmhg. mmhg

Score 1. [Chang7 5.P.013.] Convert 295 mmhg to kpa. kpa Convert 2.0 kpa to mmhg. mmhg 2. [Chang7 5.P.019.] The volume of a gas is 5.80 L, measured at 1.00 atm. What is the pressure of the gas in mmhg if

Chapter 5 Gas Laws Gas Laws 1. Gases are said to exert pressure. Provide a molecular-level explanation for this. 5 2 Gas Laws 2. How does a barometer measure atmospheric pressure? If the atmospheric pressure

### Static Fluids. **All simulations and videos required for this package can be found on my website, here:

DP Physics HL Static Fluids **All simulations and videos required for this package can be found on my website, here: http://ismackinsey.weebly.com/fluids-hl.html Fluids are substances that can flow, so

### Atmospheric Gases. Earth s Atmosphere extends from earth s surface to outer space. It is made up of a mixture of gases with some solids and liquids.

Earth s Atmosphere 1-1 I Objectives: Identify the gases in Earthś atmosphere Describe the structures of Earthś atmosphere. Explain what causes air pressure. Atmospheric Gases Earth s Atmosphere extends

### PROPERTIES OF GASES. [MH5; Ch 5, (only)]

PROPERTIES OF GASES [MH5; Ch 5, 5.1-5.5 (only)] FEATURES OF A GAS Molecules in a gas are a long way apart (under normal conditions). Molecules in a gas are in rapid motion in all directions. The forces

### VI. Static Stability. Consider a parcel of unsaturated air. Assume the actual lapse rate is less than the dry adiabatic lapse rate: Γ < Γ d

VI. Static Stability Consider a parcel of unsaturated air. Assume the actual lapse rate is less than the dry adiabatic lapse rate: Γ < Γ d VI. Static Stability Consider a parcel of unsaturated air. Assume

### Topic 6: Gases and Colligative Properties

Topic 6: Gases and Colligative Properties Ideal Gas Equation Boyle noticed an inverse relationship between volume and pressure. Pressure x volume = constant P = a P 1/P Charles found the volume of a gas,