where h = J s

Size: px
Start display at page:

Download "where h = 6.62 10-34 J s"

Transcription

1 Electromagnetic Spectrum: Refer to Figure 12.1 Molecular Spectroscopy: Absorption of electromagnetic radiation: The absorptions and emissions of electromagnetic radiation are related molecular-level phenomena of compounds. The frequency (ν) of the electromagnetic radiation and the speed with which radiation travels (c = ms -1 in vacuum) can be used to calculate the wavelength λ of the radiation. Thus, the frequency is equal to the number of waves in the radiations of an approaching beam that can arrive at receiver in 1s, and this number is equal to c/ λ. So, we can write or ν = c / λ λ = c / ν The electromagnetic radiation is also treated as stream of packets, called photons. These energies are related to frequency (ν) through Planck relation. ε = h ν where h = J s

2 Problem 1: What are the frequency and wavelength of electromagnetic radiation for which each quantum has energy of J? The energy and frequency are related to each other by Planck s relation ε = h ν where h = J s ν = ε / h = J / J s = s -1 The frequency and wavelength are related as: λ = c / ν where c = ms -1 Beer s Law: = ms -1 / s -1 = m When electromagnetic radiation is passed through a sample, some of the radiation is absorbed by the sample. The radiation absorbed by the sample is at particular frequency or of particular frequency range. We will use C for the concentration of the absorbing sample in units of moles per cubic meter.

3 The common concentration unit is M, molarity i.e. number of moles of solute per liter of solution. Then the concentration in SI units can be obtained by relation: C = M 1000 L m -3 The decrease in the intensity of an incident light beam as it passes through a sample is proportional 1. The path length 2. The concentration of the absorbing component of the solution and 3. Intensity of the beam. Thus, with the proportionality constant k, known as molar absorption coefficient, Refer to Figure 12.2 We have di = - k C I dx di / I = - k C dx Integration over a length l of the sample, di / I = d (ln I) and limits between 0 to l We get I I l di /I = d (ln I) = - k C dx

4 I 0 I 0 0 ln I / I 0 = - k C l or I = I 0 e -k C l (1) This is known as Beer s law or Beer-Lambert Law In practical analytical use, the equation (1) is converted to base-10 logarithms, concentration is expressed in moles per liter, and length is measured in centimeters. Also, the intensities of outgoing to the incoming radiation i.e. I / I 0 at any wavelength can be directly measured and is called as transmittance and the base-10 logarithmic term, log (I / I 0 ) is called as absorbance. Now, writing ε, molar extinction coefficient for proportionality constant We get, log (I / I 0 ) = ε M l or I = I ε M l (2) The equation (1) and (2) gives us the relation between k and ε as: k = ε For all theoretical purposes, we will use equation (1) and molar absorption coefficient k.

5 Thus, the extent to which radiations of particular frequencies or wavelengths is absorbed by a sample gives us absorption spectrum. In infrared spectral region, generally amount of absorption is reported as percent transmission i.e. (I/ I 0 ) 100 While in the visible and ultraviolet regions, the absorbance, log (I/ I 0 ) is used. Problem 2: In the infrared absorption spectra of ketones, aldehydes, carboxylic acids, and esters, the carbonyl absorption due to C=O group is prominent feature. For 2-butanone, or methyl ethyl ketone dissolved in carbon tetrachloride this absorption occurs at 5.8µm, or 1724 cm -1. A M solution in an absorption cell of thickness, or length, mm gives the absorption band shown in following figure. Calculate the value of molar absorption coefficient at the band maximum. Refer to Figure 12.3 From percent transmission values at the center of the absorption band and that estimated for background we obtain I = 49 I 0 = 98 ln (I/ I 0 ) = ln (0.5) = Also C = M 1000 L m -3 = mol L L m -3 = 89 mol m -3

6 l = mm = m ln I / I 0 = - k C l = - k (89 mol m -3 ) ( m) k = (0.693) / (89 mol m -3 ) ( m) = 77.5 mol -1 m 2 Rotational Spectra of Linear Molecules: The absorption of microwave radiation increases the rotational energy of the molecules and gives information about the moment of inertia of the molecules. A rotational spectrum is obtained when a sample of gas absorbs far-infrared or microwave radiation and due to this rotational-energy is changed. Rotational energies: We saw that the angular momentum and rotational energy can be given as follows: Angular momentum = J (J +1) ( h / 2π) Where J = 0,1,2,3 Rotational Energy = J (J + 1) ( h 2 / 8π 2 I ) Where J = 0,1,2,3

7 In addition, the value of J is quantized and gives us the total rotational states for a particular value of J as 2J +1. i.e. the energy levels specified by the value of J have a degeneracy of 2J + 1 Now, in order to express the rotational states of linear molecules, we use a rotational constant B given as B = ( h 2 / 8π 2 I ) Therefore, we have a rotational energy term as ε rot = J (J+1) ( h 2 / 8π 2 I ) = J (J + 1) B = BJ (J + 1) where B = ( h 2 / 8π 2 I ) and J = 0,1,2,3. Refer to Figure 12.4 Spectroscopic transitions: Most transitions between rotational states of gas phase molecules occur in the microwave region of the electromagnetic spectrum. The microwave radiation is generated in a radiolike tube known as klystron. Microwave beam can be contained in a metal tube called a wave guide into which the gas whose rotational spectrum is to be studied is placed.

8 The klystron can be tuned to produce various frequencies, and when the frequency that is absorbed by gas molecules, the electrical properties of circuits change. These absorbed frequencies can be measured accurately, thus giving a rotational spectrum of a gas sample. This is also known as farinfrared absorption spectrum. A rotating molecule interacts with electromagnetic radiation through its electric dipole. Thus, in order to get a rotational spectra: 1. The molecule must have a permanent dipole. Homonuclear molecules like N 2 and O 2 and symmetric molecules like CO 2 and CH 4 do not produce rotational spectra. 2. The transition between the adjacent states; i.e. change in the rotational quantum number J must obey a selection rule J = ± 1. Rotational Spectra: The rotational spectra or far-infrared or microwave absorption spectra of gas containing linear polar molecules show regular patterns of nearly equispaced absorption lines. Refer to Figure 12.5 Since, the rotational energies are closely spaced compared to kt, the molecules are distributed through out the lower allowed levels. Therefore, the transition can occur between many levels. The energy differences corresponds to the energies of the quanta of radiation that bring about J = + 1 transition. Therefore, the energy change due to absorption of radiation, due to J = +1 is given as: ε rot = B(J+1) (J+2) - BJ (J + 1) = B (J +1) [ (J + 2) J]

9 = 2 B (J + 1) where J = 0,1,2,3. Refer to Figure 12.6 The frequency related quantity called wave number with a symbol ν is defined as 1 / λ and therefore proportional to frequency, ν = c / λ is often expressed in terms of constant. The wave-number value is reported in units of cm -1. In this, case a rotational constant expressed in wave numbers with units of cm -1 is represented by B. The value of B with units of cm -1 is related to B with units of joules as: B = h c B Where h = J s and c = cm s -1 Thus, using the overbar to indicate the wave-number quantities, we have ε rot = ν rot = 2 B (J + 1) where J = 0,1,2,3. Thus, we expect a pattern of lines corresponding to the wave-number values 2B, 4B, 6B. and the adjacent spectral lines are spaced by a constant amount that can be identified as 2B. Using the value of B, the spacing between rotational levels can be used to find the value of B using expression B = h c B and this can be used to calculate the moment of inertia. Also, we can use the expression I = µr 2, where µ is the reduced mass, to obtain the internuclear distance, or bond length of the molecules.

10 Problem 3: The average spacing between the successive rotational absorption lines of diatomic molecules CO(g) is cm -1. Calculate the moment of inertia and the length of CO bond from this spectral result. Since the spacing between the rotational levels = 2B = cm -1 Therefore, B = cm -1 And B = h cb = ( J s ) ( cm s -1 ) ( cm -1 ) = J Now, we have B = ( h 2 / 8π 2 I ) I = ( h 2 / 8π 2 B ) = ( J s) 2 / [ (8) (3.142) 2 ( J )] = J s 2 = kg m 2 s -2 s 2

11 = kg m 2 The reduced mass of C-12 and O-16 of CO molecules can be obtained from the masses in kilograms and Avogadro s number as µ = (m 1 m 2 ) / (m 1 + m 2 ) N A = ( ) ( ) / ( ) ( ) = kg and I = µ r 2 r 2 = I / µ = kg m 2 / kg = m 2 r = m = pm

Infrared Spectroscopy: Theory

Infrared Spectroscopy: Theory u Chapter 15 Infrared Spectroscopy: Theory An important tool of the organic chemist is Infrared Spectroscopy, or IR. IR spectra are acquired on a special instrument, called an IR spectrometer. IR is used

More information

The Fundamentals of Infrared Spectroscopy. Joe Van Gompel, PhD

The Fundamentals of Infrared Spectroscopy. Joe Van Gompel, PhD TN-100 The Fundamentals of Infrared Spectroscopy The Principles of Infrared Spectroscopy Joe Van Gompel, PhD Spectroscopy is the study of the interaction of electromagnetic radiation with matter. The electromagnetic

More information

Electromagnetic Radiation

Electromagnetic Radiation Activity 17 Electromagnetic Radiation Why? Electromagnetic radiation, which also is called light, is an amazing phenomenon. It carries energy and has characteristics of both particles and waves. We can

More information

Symmetric Stretch: allows molecule to move through space

Symmetric Stretch: allows molecule to move through space BACKGROUND INFORMATION Infrared Spectroscopy Before introducing the subject of IR spectroscopy, we must first review some aspects of the electromagnetic spectrum. The electromagnetic spectrum is composed

More information

Application Note AN4

Application Note AN4 TAKING INVENTIVE STEPS IN INFRARED. MINIATURE INFRARED GAS SENSORS GOLD SERIES UK Patent App. No. 2372099A USA Patent App. No. 09/783,711 World Patents Pending INFRARED SPECTROSCOPY Application Note AN4

More information

CHAPTER 12 INFRARED SPECTROSCOPY. and MASS SPECTROSCOPY

CHAPTER 12 INFRARED SPECTROSCOPY. and MASS SPECTROSCOPY KOT 222 ORGANIC CHEMISTRY II CHAPTER 12 INFRARED SPECTROSCOPY and MASS SPECTROSCOPY Part I Infrared Spectroscopy What is Spectroscopy? Spectroscopy is the study of the interaction of matter and electromagnetic

More information

Infrared Spectroscopy

Infrared Spectroscopy Infrared Spectroscopy 1 Chap 12 Reactions will often give a mixture of products: OH H 2 SO 4 + Major Minor How would the chemist determine which product was formed? Both are cyclopentenes; they are isomers.

More information

5.33 Lecture Notes: Introduction to Spectroscopy

5.33 Lecture Notes: Introduction to Spectroscopy 5.33 Lecture Notes: ntroduction to Spectroscopy What is spectroscopy? Studying the properties of matter through its interaction with different frequency components of the electromagnetic spectrum. Latin:

More information

Infrared Spectroscopy 紅 外 線 光 譜 儀

Infrared Spectroscopy 紅 外 線 光 譜 儀 Infrared Spectroscopy 紅 外 線 光 譜 儀 Introduction Spectroscopy is an analytical technique which helps determine structure. It destroys little or no sample (nondestructive method). The amount of light absorbed

More information

INFRARED SPECTROSCOPY (IR)

INFRARED SPECTROSCOPY (IR) INFRARED SPECTROSCOPY (IR) Theory and Interpretation of IR spectra ASSIGNED READINGS Introduction to technique 25 (p. 833-834 in lab textbook) Uses of the Infrared Spectrum (p. 847-853) Look over pages

More information

Ultraviolet Spectroscopy

Ultraviolet Spectroscopy Ultraviolet Spectroscopy The wavelength of UV and visible light are substantially shorter than the wavelength of infrared radiation. The UV spectrum ranges from 100 to 400 nm. A UV-Vis spectrophotometer

More information

6. 3. Molecular spectroscopy. Unit 6: Physical chemistry of spectroscopy, surfaces and chemical and phase equilibria

6. 3. Molecular spectroscopy. Unit 6: Physical chemistry of spectroscopy, surfaces and chemical and phase equilibria 6. 3 Molecular spectroscopy Spectroscopy in its various forms is a technique with wide applications across many disciplines. From qualitative analysis in toxicology through to quantitative measurements

More information

Introduction. Chapter 12 Mass Spectrometry and Infrared Spectroscopy. Electromagnetic Spectrum. Types of Spectroscopy 8/29/2011

Introduction. Chapter 12 Mass Spectrometry and Infrared Spectroscopy. Electromagnetic Spectrum. Types of Spectroscopy 8/29/2011 Organic Chemistry, 6 th Edition L. G. Wade, Jr. Chapter 12 Mass Spectrometry and Infrared Spectroscopy Introduction Spectroscopy is an analytical technique which helps determine structure. It destroys

More information

Infrared Spectroscopy and Mass Spectrometry

Infrared Spectroscopy and Mass Spectrometry Infrared Spectroscopy and Mass Spectrometry Introduction It is fundamental for an organic chemist to be able to identify, or characterize, the new compound that he/she has just made. Sometimes this can

More information

Spectroscopy. SI Base Units

Spectroscopy. SI Base Units Spectroscopy SI Base Units m - meter - length s - second - time kg - kilogram - mass K - kelvin - thermodynamic temperature A - ampere - electric current cd - candela - luminous intensity mol - amount

More information

Info Note UV-VIS Nomenclature and Units

Info Note UV-VIS Nomenclature and Units Info Note 804: Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry (UV/VIS) involves the spectroscopy of photons in the UV-visible region. It uses light in the visible and adjacent

More information

Determining the Structure of an Organic Compound

Determining the Structure of an Organic Compound Determining the Structure of an Organic Compound The analysis of the outcome of a reaction requires that we know the full structure of the products as well as the reactants In the 19 th and early 20 th

More information

3. Electronic Spectroscopy of Molecules I - Absorption Spectroscopy

3. Electronic Spectroscopy of Molecules I - Absorption Spectroscopy 3. Electronic Spectroscopy of Molecules I - Absorption Spectroscopy 3.1. Vibrational coarse structure of electronic spectra. The Born Oppenheimer Approximation introduced in the last chapter can be extended

More information

Chapter 13 Mass Spectrometry and Infrared Spectroscopy

Chapter 13 Mass Spectrometry and Infrared Spectroscopy Chapter 13 Mass Spectrometry and Infrared Spectroscopy Copyright 2011 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Overview of Mass Spectrometry Mass spectrometry

More information

Energy (J) -8E-19 -1.2E-18 -1.6E-18 -2E-18

Energy (J) -8E-19 -1.2E-18 -1.6E-18 -2E-18 Spectrophotometry Reading assignment:. http://en.wikipedia.org/wiki/beer-lambert_law Goals We will study the spectral properties of a transition metal-containing compound. We will also study the relationship

More information

Molecular Spectroscopy:

Molecular Spectroscopy: : How are some molecular parameters determined? Bond lengths Bond energies What are the practical applications of spectroscopic knowledge? Can molecules (or components thereof) be identified based on differences

More information

electron does not become part of the compound; one electron goes in but two electrons come out.

electron does not become part of the compound; one electron goes in but two electrons come out. Characterization Techniques for Organic Compounds. When we run a reaction in the laboratory or when we isolate a compound from nature, one of our first tasks is to identify the compound that we have obtained.

More information

Interactions of Light and Matter: Spectroscopy

Interactions of Light and Matter: Spectroscopy Interactions of Light and Matter: Spectroscopy 1 Spectroscopy: Interaction of nuclei, atoms, ions, or molecules with electromagnetic radiation Based on quantum theory: quantized energy states Several possible

More information

Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry

Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry Jon H. Hardesty, PhD and Bassam Attili, PhD Collin College Department of Chemistry Introduction: In the last lab

More information

6.1 Electromagnetic Waves

6.1 Electromagnetic Waves 6.1 Electromagnetic Waves electromagnetic radiation can be described as a harmonic wave in either time or distance waves are characterized by their period, frequency, wavelength and wave number Planck's

More information

Spectroscopy. The Interaction of Electromagnetic Radiation (Light) with Molecules

Spectroscopy. The Interaction of Electromagnetic Radiation (Light) with Molecules Spectroscopy. The Interaction of Electromagnetic Radiation (Light) with Molecules (1) Electromagnetic Radiation-wave description propagation c = 3 x 10 10 cm/sec magnetic () and electric (E) field vectors

More information

CHAPTER 13 MOLECULAR SPECTROSCOPY

CHAPTER 13 MOLECULAR SPECTROSCOPY CHAPTER 13 MOLECULAR SPECTROSCOPY Our most detailed knowledge of atomic and molecular structure has been obtained from spectroscopy study of the emission, absorption and scattering of electromagnetic radiation

More information

UV-Visible Spectroscopy

UV-Visible Spectroscopy UV-Visible Spectroscopy UV-Visible Spectroscopy What is UV-Visible Spectroscopy? Molecular spectroscopy that involves study of the interaction of Ultra violet (UV)-Visible radiation with molecules What

More information

Chapter 6 Electronic Structure of Atoms

Chapter 6 Electronic Structure of Atoms Chapter 6 Electronic Structure of Atoms 1. Electromagnetic radiation travels through vacuum at a speed of m/s. (a). 6.626 x 26 (b). 4186 (c). 3.00 x 8 (d). It depends on wavelength Explanation: The speed

More information

DETERMINACIÓN DE ESTRUCTURAS ORGÁNICAS (ORGANIC SPECTROSCOPY) IR SPECTROSCOPY

DETERMINACIÓN DE ESTRUCTURAS ORGÁNICAS (ORGANIC SPECTROSCOPY) IR SPECTROSCOPY DETERMINACIÓN DE ESTRUCTURAS ORGÁNICAS (ORGANIC SPECTROSCOPY) IR SPECTROSCOPY Hermenegildo García Gómez Departamento de Química Instituto de Tecnología Química Universidad Politécnica de Valencia 46022

More information

3.1 Photoelectricity AS13. 3.1 Photo-electricity 2

3.1 Photoelectricity AS13. 3.1 Photo-electricity 2 Photo-electricity Einstein s quantum explanation of the photoelectric effect - Einstein used Planck s quantum theory of radiation, (see Revision Card AS1), to explain photoelectric emission. He assumed

More information

Chemistry 111 Lab: Intro to Spectrophotometry Page E-1

Chemistry 111 Lab: Intro to Spectrophotometry Page E-1 Chemistry 111 Lab: Intro to Spectrophotometry Page E-1 SPECTROPHOTOMETRY Absorption Measurements & their Application to Quantitative Analysis study of the interaction of light (or other electromagnetic

More information

The Electronic Structures of Atoms Electromagnetic Radiation

The Electronic Structures of Atoms Electromagnetic Radiation The Electronic Structures of Atoms Electromagnetic Radiation The wavelength of electromagnetic radiation has the symbol λ. Wavelength is the distance from the top (crest) of one wave to the top of the

More information

Chapter 6 Electromagnetic Radiation and the Electronic Structure of the Atom

Chapter 6 Electromagnetic Radiation and the Electronic Structure of the Atom Chapter 6 In This Chapter Physical and chemical properties of compounds are influenced by the structure of the molecules that they consist of. Chemical structure depends, in turn, on how electrons are

More information

COLORS WE CONSUME A spectroscopic analysis of FD&C food colors in soda pop

COLORS WE CONSUME A spectroscopic analysis of FD&C food colors in soda pop COLORS WE CONSUME A spectroscopic analysis of FD&C food colors in soda pop LAB VIS 12 Used with permission by Gary Krenzer, Mercer High School, Dr. Charles Kriley and Dr. Harold Condor, Grove City College.

More information

Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation

Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation Outline MAE 493R/593V- Renewable Energy Devices Solar Energy Electromagnetic wave Solar spectrum Solar global radiation Solar thermal energy Solar thermal collectors Solar thermal power plants Photovoltaics

More information

Workshop: Diatomic molecule vibrational and rotational spectra Quantum aspects of physical chemistry

Workshop: Diatomic molecule vibrational and rotational spectra Quantum aspects of physical chemistry Workshop: Diatomic molecule vibrational and rotational spectra Quantum aspects of physical chemistry http://quantum.bu.edu/pltl/8/8.pdf Last updated Tuesday, November 5, 005 :5:35-05:00 Copyright 005 Dan

More information

Absorption of IR Light

Absorption of IR Light Absorption of IR Light Absorption of IR light causes changes in the vibrational motions of a molecule. The different vibrational modes available to a molecule include stretching and bending modes. The

More information

Lecture Topics: I. IR spectroscopy

Lecture Topics: I. IR spectroscopy IR and Mass Spectrometry Reading: Wade chapter 12, sections 12-1- 12-15 Study Problems: 12-15, 12-16, 12-23, 12-25 Key Concepts and Skills: Given an IR spectrum, identify the reliable characteristic peaks

More information

2. Molecular stucture/basic

2. Molecular stucture/basic 2. Molecular stucture/basic spectroscopy The electromagnetic spectrum Spectral region for atomic and molecular spectroscopy E. Hecht (2nd Ed.) Optics, Addison-Wesley Publishing Company,1987 Spectral regions

More information

1 Spectrophotometric Analysis of Commercial Aspirin

1 Spectrophotometric Analysis of Commercial Aspirin 1 Spectrophotometric Analysis of Commercial Aspirin Name: _ Date: Lab Day/Time: Lab Partner: Objectives Learn about the absorption of light by molecules Learn the basic components of a spectrophotometer

More information

Austin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law

Austin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law Purpose To become familiar with using a spectrophotometer and gain an understanding of Beer s law and it s relationship to solution concentration. Introduction Scientists use many methods to determine

More information

Module 3 : Molecular Spectroscopy Lecture 13 : Rotational and Vibrational Spectroscopy

Module 3 : Molecular Spectroscopy Lecture 13 : Rotational and Vibrational Spectroscopy Module 3 : Molecular Spectroscopy Lecture 13 : Rotational and Vibrational Spectroscopy Objectives After studying this lecture, you will be able to Calculate the bond lengths of diatomics from the value

More information

0 10 20 30 40 50 60 70 m/z

0 10 20 30 40 50 60 70 m/z Mass spectrum for the ionization of acetone MS of Acetone + Relative Abundance CH 3 H 3 C O + M 15 (loss of methyl) + O H 3 C CH 3 43 58 0 10 20 30 40 50 60 70 m/z It is difficult to identify the ions

More information

Experiment #5: Qualitative Absorption Spectroscopy

Experiment #5: Qualitative Absorption Spectroscopy Experiment #5: Qualitative Absorption Spectroscopy One of the most important areas in the field of analytical chemistry is that of spectroscopy. In general terms, spectroscopy deals with the interactions

More information

Problem Set 6 UV-Vis Absorption Spectroscopy. 13-1. Express the following absorbances in terms of percent transmittance:

Problem Set 6 UV-Vis Absorption Spectroscopy. 13-1. Express the following absorbances in terms of percent transmittance: Problem Set 6 UV-Vis Absorption Spectroscopy 13-1. Express the following absorbances in terms of percent transmittance: a 0.051 b 0.918 c 0.379 d 0.261 e 0.485 f 0.072 A = log P o /P = log1/t = - log T

More information

VISIBLE SPECTROSCOPY

VISIBLE SPECTROSCOPY VISIBLE SPECTROSCOPY Visible spectroscopy is the study of the interaction of radiation from the visible part (λ = 380-720 nm) of the electromagnetic spectrum with a chemical species. Quantifying the interaction

More information

Organic Chemistry Tenth Edition

Organic Chemistry Tenth Edition Organic Chemistry Tenth Edition T. W. Graham Solomons Craig B. Fryhle Welcome to CHM 22 Organic Chemisty II Chapters 2 (IR), 9, 3-20. Chapter 2 and Chapter 9 Spectroscopy (interaction of molecule with

More information

Time out states and transitions

Time out states and transitions Time out states and transitions Spectroscopy transitions between energy states of a molecule excited by absorption or emission of a photon hn = DE = E i - E f Energy levels due to interactions between

More information

AP CHEMISTRY 2007 SCORING GUIDELINES (Form B)

AP CHEMISTRY 2007 SCORING GUIDELINES (Form B) Answer the following problems about gases. AP CHEMISTRY 2007 SCORING GUIDELINES (Form B) Question 2 (a) The average atomic mass of naturally occurring neon is 20.18 amu. There are two common isotopes of

More information

Chemistry 102 Summary June 24 th. Properties of Light

Chemistry 102 Summary June 24 th. Properties of Light Chemistry 102 Summary June 24 th Properties of Light - Energy travels through space in the form of electromagnetic radiation (EMR). - Examples of types of EMR: radio waves, x-rays, microwaves, visible

More information

- the total energy of the system is found by summing up (integrating) over all particles n(ε) at different energies ε

- the total energy of the system is found by summing up (integrating) over all particles n(ε) at different energies ε Average Particle Energy in an Ideal Gas - the total energy of the system is found by summing up (integrating) over all particles n(ε) at different energies ε - with the integral - we find - note: - the

More information

Fundamentals of molecular absorption spectroscopy (UV/VIS)

Fundamentals of molecular absorption spectroscopy (UV/VIS) 10.2.1.3 Molecular spectroscopy 10.2.1.3.1 Introduction Molecular radiation results from the rotational, vibrational and electronic energy transitions of molecules. Band spectra are the combination of

More information

Atomic Structure Ron Robertson

Atomic Structure Ron Robertson Atomic Structure Ron Robertson r2 n:\files\courses\1110-20\2010 possible slides for web\atomicstructuretrans.doc I. What is Light? Debate in 1600's: Since waves or particles can transfer energy, what is

More information

Finding The Energy of a Photon. F Scullion Some useful rearrangement triangles. Also note that 1 mole = 6.

Finding The Energy of a Photon. F Scullion  Some useful rearrangement triangles. Also note that 1 mole = 6. 1 Atomic Theory. Finding The Energy of a Photon F Scullion www.justchemy.com Some useful rearrangement triangles The Relationship between light and energy Converting frequency to wavelength Also note that

More information

Preview of Period 3: Electromagnetic Waves Radiant Energy II

Preview of Period 3: Electromagnetic Waves Radiant Energy II Preview of Period 3: Electromagnetic Waves Radiant Energy II 3.1 Radiant Energy from the Sun How is light reflected and transmitted? What is polarized light? 3.2 Energy Transfer with Radiant Energy How

More information

Radiation Transfer in Environmental Science

Radiation Transfer in Environmental Science Radiation Transfer in Environmental Science with emphasis on aquatic and vegetation canopy media Autumn 2008 Prof. Emmanuel Boss, Dr. Eyal Rotenberg Introduction Radiation in Environmental sciences Most

More information

Further Modification of JB s criticism of the FM Paper in E & E

Further Modification of JB s criticism of the FM Paper in E & E Further Modification of JB s criticism of the FM Paper in E & E This is a shortened and updated version of my criticism of FM s paper [THE STABLE STATIONARY VALUE OF THE EARTH S GLOBAL AVERAGE ATMOSPHERIC

More information

CHEM344 HW#7 Due: Fri, Mar BEFORE CLASS!

CHEM344 HW#7 Due: Fri, Mar BEFORE CLASS! CHEM344 HW#7 Due: Fri, Mar 14@2pm BEFORE CLASS! HW to be handed in: Atkins Chapter 8: Exercises: 8.11(b), 8.16(b), 8.19(b), Problems: 8.2, 8.4, 8.12, 8.34, Chapter 9: Exercises: 9.5(b), 9.7(b), Extra (do

More information

Problem Set 1 Solutions

Problem Set 1 Solutions Chemistry 36 Dr. Jean M. Standard Problem Set Solutions. The first 4 lines in the visible region of atomic line spectrum of hydrogen atom occur at wavelengths of 656., 486., 434.0, and 40. nm (this is

More information

SPECTROPHOTOMETRY. Blue. Orange

SPECTROPHOTOMETRY. Blue. Orange Appendix I FV /26/5 SPECTROPHOTOMETRY Spectrophotometry is an analytical technique used to measure the amount of light of a particular wavelength absorbed by a sample in solution. This measurement is then

More information

13C NMR Spectroscopy

13C NMR Spectroscopy 13 C NMR Spectroscopy Introduction Nuclear magnetic resonance spectroscopy (NMR) is the most powerful tool available for structural determination. A nucleus with an odd number of protons, an odd number

More information

Electromagnetic Radiation

Electromagnetic Radiation Forms of Energy There are many types of energy. Kinetic energy is the energy of motion. Potential energy is energy that results from position, such as the energy in water going over a dam. Electrical energy

More information

COLLEGE PHYSICS. Chapter 29 INTRODUCTION TO QUANTUM PHYSICS

COLLEGE PHYSICS. Chapter 29 INTRODUCTION TO QUANTUM PHYSICS COLLEGE PHYSICS Chapter 29 INTRODUCTION TO QUANTUM PHYSICS Quantization: Planck s Hypothesis An ideal blackbody absorbs all incoming radiation and re-emits it in a spectrum that depends only on temperature.

More information

Absorption by atmospheric gases in the IR, visible and UV spectral regions.

Absorption by atmospheric gases in the IR, visible and UV spectral regions. Lecture 6. Absorption by atmospheric gases in the IR, visible and UV spectral regions. Objectives: 1. Gaseous absorption in thermal IR. 2. Gaseous absorption in the visible and near infrared. 3. Gaseous

More information

Concept 2. A. Description of light-matter interaction B. Quantitatities in spectroscopy

Concept 2. A. Description of light-matter interaction B. Quantitatities in spectroscopy Concept 2 A. Description of light-matter interaction B. Quantitatities in spectroscopy Dipole approximation Rabi oscillations Einstein kinetics in two-level system B. Absorption: quantitative description

More information

ENERGY METEOROLOGY. UNIT 1: Basics of Radiation. Energy transfer through radiation. Concept of blackbody radiation, Kirchhoff s law

ENERGY METEOROLOGY. UNIT 1: Basics of Radiation. Energy transfer through radiation. Concept of blackbody radiation, Kirchhoff s law UNIT 1: Basics of Radiation Energy transfer through radiation Concept of blackbody radiation, Kirchhoff s law Radiation laws of Planck, Stefan-Boltzmann and Wien Radiation quantities Examples Radiative

More information

EXPERIMENT 11 UV/VIS Spectroscopy and Spectrophotometry: Spectrophotometric Analysis of Potassium Permanganate Solutions.

EXPERIMENT 11 UV/VIS Spectroscopy and Spectrophotometry: Spectrophotometric Analysis of Potassium Permanganate Solutions. EXPERIMENT 11 UV/VIS Spectroscopy and Spectrophotometry: Spectrophotometric Analysis of Potassium Permanganate Solutions. Outcomes After completing this experiment, the student should be able to: 1. Prepare

More information

passing through (Y-axis). The peaks are those shown at frequencies when less than

passing through (Y-axis). The peaks are those shown at frequencies when less than Infrared Spectroscopy used to analyze the presence of functional groups (bond types) in organic molecules The process for this analysis is two-fold: 1. Accurate analysis of infrared spectra to determine

More information

Light is a type of electromagnetic (EM) radiation, and light has energy. Many kinds of light exist. Ultraviolet (UV) light causes skin to tan or burn.

Light is a type of electromagnetic (EM) radiation, and light has energy. Many kinds of light exist. Ultraviolet (UV) light causes skin to tan or burn. Light and radiation Light is a type of electromagnetic (EM) radiation, and light has energy. Many kinds of light exist. Ultraviolet (UV) light causes skin to tan or burn. Infrared (IR) light is used in

More information

Blackbody radiation derivation of Planck s radiation low

Blackbody radiation derivation of Planck s radiation low Blackbody radiation derivation of Planck s radiation low 1 Classical theories of Lorentz and Debye: Lorentz (oscillator model): Electrons and ions of matter were treated as a simple harmonic oscillators

More information

WAVES AND PARTICLES. (v) i.e (vi) The potential difference required to bring an electron of wavelength to rest

WAVES AND PARTICLES. (v) i.e (vi) The potential difference required to bring an electron of wavelength to rest WAVES AND PARTICLES 1. De Broglie wavelength associated with the charges particles (i) The energy of a charged particle accelerated through potential difference q = charge on the particel (ii) Momentum

More information

Electromagnetic Radiation and Atomic Spectra POGIL

Electromagnetic Radiation and Atomic Spectra POGIL Name _Key AP Chemistry Electromagnetic Radiation and Atomic Spectra POGIL Electromagnetic Radiation Model 1: Characteristics of Waves The figure above represents part of a wave. The entire wave can be

More information

PRACTICE EXAM IV P202 SPRING 2004

PRACTICE EXAM IV P202 SPRING 2004 PRACTICE EXAM IV P202 SPRING 2004 1. In two separate double slit experiments, an interference pattern is observed on a screen. In the first experiment, violet light (λ = 754 nm) is used and a second-order

More information

Name Date Class ELECTRONS IN ATOMS. Standard Curriculum Core content Extension topics

Name Date Class ELECTRONS IN ATOMS. Standard Curriculum Core content Extension topics 13 ELECTRONS IN ATOMS Conceptual Curriculum Concrete concepts More abstract concepts or math/problem-solving Standard Curriculum Core content Extension topics Honors Curriculum Core honors content Options

More information

Energy Transport. Focus on heat transfer. Heat Transfer Mechanisms: Conduction Radiation Convection (mass movement of fluids)

Energy Transport. Focus on heat transfer. Heat Transfer Mechanisms: Conduction Radiation Convection (mass movement of fluids) Energy Transport Focus on heat transfer Heat Transfer Mechanisms: Conduction Radiation Convection (mass movement of fluids) Conduction Conduction heat transfer occurs only when there is physical contact

More information

Organic Spectroscopy. UV - Ultraviolet-Visible Spectroscopy. !! 200-800 nm. Methods for structure determination of organic compounds:

Organic Spectroscopy. UV - Ultraviolet-Visible Spectroscopy. !! 200-800 nm. Methods for structure determination of organic compounds: Organic Spectroscopy Methods for structure determination of organic compounds: X-ray rystallography rystall structures Mass spectroscopy Molecular formula -----------------------------------------------------------------------------

More information

Wave Properties of Electromagnetic Radiation

Wave Properties of Electromagnetic Radiation Wave Properties of Electromagnetic Radiation Two options are available for analytical utility when an analyte interacts with a beam of electromagnetic radiation in an instrument 1. We can monitor the changes

More information

Sample Exercise 6.1 Concepts of Wavelength and Frequency

Sample Exercise 6.1 Concepts of Wavelength and Frequency Sample Exercise 6.1 Concepts of Wavelength and Frequency Two electromagnetic waves are represented in the margin. (a) Which wave has the higher frequency? (b) If one wave represents visible light and the

More information

(3)

(3) 1. Organic compounds are often identified by using more than one analytical technique. Some of these techniques were used to identify the compounds in the following reactions. C 3 H 7 Br C 3 H 8 O C 3

More information

Chapter 7. Quantum Theory and Atomic Structure

Chapter 7. Quantum Theory and Atomic Structure Chapter 7. Quantum Theory and Atomic Structure A problem arose in Rutherford s nuclear model. A nucleus and electron attract each other; to remain apart the electron must move. The energy of the electron

More information

The greenhouse effect and global warming

The greenhouse effect and global warming CA1. The greenhouse effect and global warming. Vicky Wong Page 1 of 7 The greenhouse effect and global warming The sun produces radiation mainly in the ultraviolet (UV), visible (vis) and infrared (IR)

More information

Atomic Emission Spectra (Teacher Demonstration)

Atomic Emission Spectra (Teacher Demonstration) SKILL FOCUS Analyzing and interpreting Communicating results Atomic Emission Spectra (Teacher Demonstration) When a high voltage current is passed through a glass tube that contains hydrogen gas at low

More information

Ultraviolet - Visible Spectroscopy (UV)

Ultraviolet - Visible Spectroscopy (UV) UV Ultraviolet - Visible Spectroscopy (UV) Introduction to Ultraviolet - Visible Spectroscopy 1 (UV) Background Theory UV Absorption of ultraviolet and visible radiation Absorption of visible and ultraviolet

More information

Using the Spectrophotometer

Using the Spectrophotometer Using the Spectrophotometer Introduction In this exercise, you will learn the basic principals of spectrophotometry and and serial dilution and their practical application. You will need these skills to

More information

Upon completion of this lab, the student will be able to:

Upon completion of this lab, the student will be able to: 1 Learning Outcomes EXPERIMENT B4: CHEMICAL EQUILIBRIUM Upon completion of this lab, the student will be able to: 1) Analyze the absorbance spectrum of a sample. 2) Calculate the equilibrium constant for

More information

Raman Scattering Theory David W. Hahn Department of Mechanical and Aerospace Engineering University of Florida (dwhahn@ufl.edu)

Raman Scattering Theory David W. Hahn Department of Mechanical and Aerospace Engineering University of Florida (dwhahn@ufl.edu) Introduction Raman Scattering Theory David W. Hahn Department of Mechanical and Aerospace Engineering University of Florida (dwhahn@ufl.edu) The scattering of light may be thought of as the redirection

More information

WAVES AND ELECTROMAGNETIC RADIATION

WAVES AND ELECTROMAGNETIC RADIATION WAVES AND ELECTROMAGNETIC RADIATION All waves are characterized by their wavelength, frequency and speed. Wavelength (lambda, ): the distance between any 2 successive crests or troughs. Frequency (nu,):

More information

Lab #11: Determination of a Chemical Equilibrium Constant

Lab #11: Determination of a Chemical Equilibrium Constant Lab #11: Determination of a Chemical Equilibrium Constant Objectives: 1. Determine the equilibrium constant of the formation of the thiocyanatoiron (III) ions. 2. Understand the application of using a

More information

1.3.6 Electromagnetic radiation. Name Symbol Definition SI unit Notes

1.3.6 Electromagnetic radiation. Name Symbol Definition SI unit Notes 1.3.6 Electromagnetic radiation Name Symbol Definition SI unit Notes wavelength λ m speed of light in vacuum c0 c0 = 299 792 458 m s -1 m s -1 (1) in medium c c = c0/n m s -1 wavenumber in vacuum ~ ν ~

More information

Determination of Molecular Structure by MOLECULAR SPECTROSCOPY

Determination of Molecular Structure by MOLECULAR SPECTROSCOPY Determination of Molecular Structure by MOLEULAR SPETROSOPY hemistry 3 B.Z. Shakhashiri Fall 29 Much of what we know about molecular structure has been learned by observing and analyzing how electromagnetic

More information

nm cm meters VISIBLE UVB UVA Near IR 200 300 400 500 600 700 800 900 nm

nm cm meters VISIBLE UVB UVA Near IR 200 300 400 500 600 700 800 900 nm Unit 5 Chapter 13 Electrons in the Atom Electrons in the Atom (Chapter 13) & The Periodic Table/Trends (Chapter 14) Niels Bohr s Model Recall the Evolution of the Atom He had a question: Why don t the

More information

Electronic Structure and the Periodic Table Learning Outcomes

Electronic Structure and the Periodic Table Learning Outcomes Electronic Structure and the Periodic Table Learning Outcomes (a) Electronic structure (i) Electromagnetic spectrum and associated calculations Electromagnetic radiation may be described in terms of waves.

More information

Atomic and Nuclear Physics Laboratory (Physics 4780)

Atomic and Nuclear Physics Laboratory (Physics 4780) Gamma Ray Spectroscopy Week of September 27, 2010 Atomic and Nuclear Physics Laboratory (Physics 4780) The University of Toledo Instructor: Randy Ellingson Gamma Ray Production: Co 60 60 60 27Co28Ni *

More information

Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing

Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing LA502 Special Studies Remote Sensing Electromagnetic Radiation (EMR) Dr. Ragab Khalil Department of Landscape Architecture Faculty of Environmental Design King AbdulAziz University Room 103 Overview What

More information

Lecture 1: Basic Concepts on Absorption and Fluorescence

Lecture 1: Basic Concepts on Absorption and Fluorescence Lecture 1: Basic Concepts on Absorption and Fluorescence Nicholas G. James Cell and Molecular Biology University of Hawaii at Manoa, Honolulu The Goal The emission of light after absorption of an outside

More information

Chapter 18 Let there be light Overhead Fig 18-2 problems: 3, 8, 9, 11,13, 17, 20, 21

Chapter 18 Let there be light Overhead Fig 18-2 problems: 3, 8, 9, 11,13, 17, 20, 21 Chapter 18 Let there be light Overhead Fig 18-2 problems: 3, 8, 9, 11,13, 17, 20, 21 18-1 Properties of light We are all familiar with the wave picture of light. For simplicity we diagram a plane polarized

More information

Energy. Mechanical Energy

Energy. Mechanical Energy Principles of Imaging Science I (RAD119) Electromagnetic Radiation Energy Definition of energy Ability to do work Physicist s definition of work Work = force x distance Force acting upon object over distance

More information

Spectroscopy. Biogeochemical Methods OCN 633. Rebecca Briggs

Spectroscopy. Biogeochemical Methods OCN 633. Rebecca Briggs Spectroscopy Biogeochemical Methods OCN 633 Rebecca Briggs Definitions of Spectrometry Defined by the method used to prepare the sample 1. Optical spectrometry Elements are converted to gaseous atoms or

More information