Transcript Chapter 2
Chapter 2 Atoms, Molecules & Ions Dr. S. M. Condren Quantum Corral http://www.almaden.ibm.com/vis/stm/corral.html Dr. S. M. Condren Scanning Tunneling Microscope Dr. S. M. Condren Scanning Tunneling Microscope Dr. S. M. Condren Scanning Tunneling Microscope Dr. S. M. Condren http://www.cbu.edu/~mcondren/SeeAtoms.htm Dr. S. M. Condren Developed in collaboration with the Institute for Chemical Education and the Magnetic Microscopy Center University of Minnesota http://www.physics.umn.edu/groups/mmc/ Dr. S. M. Condren http://mrsec.wisc.edu/ http://mrsec.wisc.edu/ Sample http://www.nsf.gov/mps/dmr/mrsec.htm http://www.nsf.gov/mps/dmr/mrsec.htm Probe Pull Probe Strip Dr. S. M. Condren Pull Probe Strip Which best represents the poles? (a) (b) (c) North South Dr. S. M. Condren Atoms & Molecules Atoms • can exist alone or enter into chemical combination • the smallest indivisible particle of an element Molecules • a combination of atoms that has its own characteristic set of properties Dr. S. M. Condren Law of Constant Composition A chemical compound always contains the same elements in the same proportions by mass. Dr. S. M. Condren Law of Multiple Proportions • the same elements can be combined to form different compounds by combining the elements in different proportions Dr. S. M. Condren Dalton’s Atomic Theory Postulates • proposed in 1803 • know at least 2 for first exam Dr. S. M. Condren Dalton’s Atomic Theory Postulate 1 • An element is composed of tiny particles called atoms. • All atoms of a given element show the same chemical properties. Dr. S. M. Condren Dalton’s Atomic Theory Postulate 2 • Atoms of different elements have different properties. Dr. S. M. Condren Dalton’s Atomic Theory Postulate 3 • Compounds are formed when atoms of two or more elements combine. • In a given compound, the relative number of atoms of each kind are definite and constant. Dr. S. M. Condren Dalton’s Atomic Theory Postulate 4 • In an ordinary chemical reaction, no atom of any element disappears or is changed into an atom of another element. • Chemical reactions involve changing the way in which the atoms are joined together. Dr. S. M. Condren Radioactivity Dr. S. M. Condren Radioactivity • Alpha – helium-4 nucleus • Beta – high energy electron • Gamma – energy resulting from transitions from one nuclear energy level to another Dr. S. M. Condren Alpha Radiation • • • • • • composed of 2 protons and 2 neutrons thus, helium-4 nucleus +2 charge mass of 4 amu creates element with atomic number 2 lower Ra226 Rn222 + He4(a) Dr. S. M. Condren Beta Radiation • composed of a high energy electron which was ejected from the nucleus • “neutron” converted to “proton” • very little mass • -1 charge • creates element with atomic number 1 higher • U239 Np239 + b-1 Dr. S. M. Condren Gamma Radiation • nucleus has energy levels • energy released from nucleus as the nucleus changes from higher to lower energy levels • no mass • no charge • Ni60* Ni60 + g Dr. S. M. Condren Cathode Ray Tube Dr. S. M. Condren Thompson’s Charge/Mass Ratio Dr. S. M. Condren Millikin’s Oil Drop Dr. S. M. Condren Rutherford’s Gold Foil Dr. S. M. Condren Rutherford’s Model of the Atom Dr. S. M. Condren Rutherford’s Model of the Atom • atom is composed mainly of vacant space • all the positive charge and most of the mass is in a small area called the nucleus • electrons are in the electron cloud surrounding the nucleus Dr. S. M. Condren Structure of the Atom Composed of: • protons • neutrons • electrons Dr. S. M. Condren Structure of the Atom Composed of: • protons • neutrons • electrons • protons – found in nucleus – relative charge of +1 – relative mass of 1.0073 amu Dr. S. M. Condren Structure of the Atom Composed of: • protons • neutrons • electrons • neutrons – found in nucleus – neutral charge – relative mass of 1.0087 amu Dr. S. M. Condren Structure of the Atom Composed of: • protons • neutrons • electrons • electrons – found in electron cloud – relative charge of -1 – relative mass of 0.00055 amu Dr. S. M. Condren Size of Nucleus If the nucleus were 1” in diameter, the atom would be 1.5 miles in diameter. Dr. S. M. Condren Ions • charged single atom • charged cluster of atoms Dr. S. M. Condren Ions • cations – positive ions • anions – negative ions • ionic compounds – combination of cations and anions – zero net charge Dr. S. M. Condren Atomic number, Z • the number of protons in the nucleus • the number of electrons in a neutral atom • the integer on the periodic table for each element Dr. S. M. Condren Isotopes • atoms of the same element which differ in the number of neutrons in the nucleus • designated by mass number Dr. S. M. Condren Mass Number, A • integer representing the approximate mass of an atom • equal to the sum of the number of protons and neutrons in the nucleus Dr. S. M. Condren Masses of Atoms Carbon-12 Scale Dr. S. M. Condren Isotopes of Hydrogen H-1, 1H, protium • 1 proton and no neutrons in nucleus • only isotope of any element containing no neutrons in the nucleus • most common isotope of hydrogen Dr. S. M. Condren Isotopes of Hydrogen H-2 or D, 2H, deuterium • 1 proton and 1 neutron in nucleus Dr. S. M. Condren Isotopes of Hydrogen H-3 or T, 3H, tritium • 1 proton and 2 neutrons in nucleus Dr. S. M. Condren Isotopes of Oxygen O-16 • 8 protons, 8 neutrons, & 8 electrons O-17 • 8 protons, 9 neutrons, & 8 electrons O-18 • 8 protons, 10 neutrons, & 8 electrons Dr. S. M. Condren The radioactive isotope 14C has how many neutrons? 6, 8, other Dr. S. M. Condren The identity of an element is determined by the number of which particle? protons, neutrons, electrons Dr. S. M. Condren Mass Spectrometer Dr. S. M. Condren Mass Spectra of Neon Dr. S. M. Condren Measurement of Atomic Masses Mass Spectrometer a simulation is available at http://www.colby.edu/chemistry/ OChem/DEMOS/MassSpec.html Dr. S. M. Condren Atomic Masses and Isotopic Abundances natural atomic masses = sum[(atomic mass of isotope) *(fractional isotopic abundance)] Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x+y=1 y=1-x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 Thus: 34.96885*x + 36.96590*y = 35.453 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 y=1-x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 x + y = 1 <=> 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 1.99705x = 1.5129 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 1.99705x = 1.5129 x = 0.7553 <=> 75.53% Cl-35 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 1.99705x = 1.5129 x = 0.7553 <=> 75.53% Cl-35 y=1-x Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 1.99705x = 1.5129 x = 0.7553 <=> 75.53% Cl-35 y = 1 - x = 1.0000 - 0.7553 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 1.99705x = 1.5129 x = 0.7553 <=> 75.53% Cl-35 y = 1 - x = 1.0000 - 0.7553 = 0.2447 Dr. S. M. Condren Example: Chlorine has two isotopes, Cl-35 and Cl-37, which have masses of 34.96885 and 36.96590 amu, respectively. The natural atomic mass of chlorine is 35.453 amu. What are the percent abundances of the two isotopes? let x = fraction Cl-35 y = fraction Cl-37 x + y = 1 <=> y = 1 - x (AW Cl-35)(fraction Cl-35) + (AW Cl-37)(fraction Cl-37) = 35.453 34.96885*x + 36.96590*y = 35.453 34.96885*x + 36.96590*(1-x) = 35.453 (34.96885 - 36.96590)x + 36.96590 = 35.453 (34.96885 - 36.96590)x = (35.453 - 36.96590) - 1.99705x = - 1.5129 1.99705x = 1.5129 x = 0.7553 <=> 75.53% Cl-35 y = 1 - x = 1.0000 - 0.7553 = 0.2447 24.47% Cl-37 Dr. S. M. Condren Development of Periodic Table Newlands - English 1864 - Law of Octaves - every 8th element has similar properties Dr. S. M. Condren Development of Periodic Table Dmitri Mendeleev - Russian 1869 - Periodic Law - allowed him to predict properties of unknown elements Dr. S. M. Condren Mendeleev’s Periodic Table the elements are arranged according to increasing atomic weights Dr. S. M. Condren Mendeleev’s Periodic Table Missing elements: 44, 68, 72, & 100 amu Dr. S. M. Condren Properties of Ekasilicon Dr. S. M. Condren Modern Periodic Table Moseley, Henry Gwyn Jeffreys 1887–1915, English physicist. Studied the relations among bright-line spectra of different elements. Derived the ATOMIC NUMBERS from the frequencies of vibration of X-rays emitted by each element. Moseley concluded that the atomic number is equal to the charge on the nucleus. This work explained discrepancies in Mendeleev’s Periodic Law. Dr. S. M. Condren Modern Periodic Table the elements are arranged according to increasing atomic numbers Dr. S. M. Condren Periodic Table of the Periodic Table of the Elements Elements IA 1 1 3 4 5 6 7 III B IV B VB VI B VII B VIII B IB II B III A IV A VA VI A VII A 1 VIII A 2 H H He 1.008 1.008 4.0026 10 3 2 II A 4 5 6 7 8 9 Li Be B C N O F Ne 6.939 9.0122 10.811 12.011 14.007 15.999 18.998 20.183 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar 22.99 24.312 26.982 28.086 30.974 32.064 35.453 39.948 19 20 31 32 33 34 35 36 21 22 23 24 25 26 27 28 29 30 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se 39.102 40.08 44.956 47.89 50.942 51.996 54.938 55.847 58.932 58.71 63.54 65.37 69.72 72.59 74.922 78.96 Br 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 85.468 87.62 88.906 91.224 92.906 95.94 * 98 101.07 102.91 106.42 107.9 112.41 114.82 118.71 121.75 127.61 126.9 131.29 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 79.909 Kr 83.8 Cs Ba **La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 132.91 137.33 138.91 178.49 180.95 183.85 186.21 190.2 192.22 195.08 196.97 200.29 204.38 207.2 208.98 * 209 * 210 * 222 87 88 89 104 105 106 107 108 109 110 111 112 113 114 115 116 Rf Ha Sg Ns Hs Mt * 261 * 262 * 263 * 262 * 265 * 268 Fr * 223 Ra ***Ac 226.03 227.03 58 * Designates that **Lanthanum all isotopes are Series radioactive *** Actinium Series 59 60 61 62 Uun Uuu Uub * 269 * 272 63 64 * 277 65 Uut 118 Uuq Uup Uuh Uuo *284 *285 *288 *292 Based on symbols used by ACS 66 67 68 69 S.M.Condren 2007 *294 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140.12 140.91 144.24 * 145 150.36 151.96 157.25 158.93 162.51 164.93 167.26 168.93 173.04 174.97 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 232.04 231.04 238.03 237.05 * 244 * 243 * 247 * 247 * 251 * 252 * 257 * 258 * 259 * 260 Dr. S. M. Condren Organization of Periodic Table • period - horizontal row • group - vertical column Dr. S. M. Condren Family Names Group IA alkali metals Group IIA alkaline earth metals Group VIIA halogens Group VIIIA noble gases transition metals inner transition metals • lanthanum series rare earths • actinium series trans-uranium series Dr. S. M. Condren Types of Elements metals nonmetals metalloids - semimetals Dr. S. M. Condren Elements, Compounds, and Formulas Elements • can exist as single atoms or molecules Compounds • combination of two or more elements • molecular formulas for molecular compounds • empirical formulas for ionic compounds Dr. S. M. Condren Organic Compounds Organic Chemistry • branch of chemistry in which carbon compounds and their reactions are studied. • the chemistry of carbon-hydrogen compounds Dr. S. M. Condren Inorganic Compounds Inorganic Chemistry • field of chemistry in which are studied the chemical reactions and properties of all the chemical elements and their compounds, with the exception of the hydrocarbons (compounds composed of carbon and hydrogen) and their derivatives. Dr. S. M. Condren Molecular and Structural Formulas Dr. S. M. Condren Bulk Substances • mainly ionic compounds – empirical formulas – structural formulas Dr. S. M. Condren Models of Sodium Chloride NaCl “table salt” Dr. S. M. Condren How many atoms are in the formula Al2(SO4)3? 3, 5, 17 Dr. S. M. Condren Naming Binary Molecular Compounds • For compounds composed of two nonmetallic elements, the more metallic element is listed first. • To designate the multiplicity of an element, Greek prefixes are used: mono => 1; di => 2; tri => 3; tetra => 4; penta => 5; hexa => 6; hepta => 7; octa => 8 Dr. S. M. Condren Common Compounds H2O water NH3 ammonia N2O nitrous oxide CO carbon monoxide CS2 SO3 sulfur trioxide CCl4 carbon tetrachloride PCl5 phosphorus pentachloride SF6 sulfur hexafluoride carbon disulfide Dr. S. M. Condren Alkanes - CnH2n+2 • • • • • methane - CH4 ethane - C2H6 propane - C3H8 butanes - C4H10 pentanes - C5H12 • • • • • hexanes - C6H14 heptanes - C7H16 octanes - C8H18 nonanes - C9H20 decanes - C10H22 Dr. S. M. Condren Burning of Propane Gas Dr. S. M. Condren Butanes Dr. S. M. Condren Ionic Bonding Characteristics of compounds with ionic bonding: • non-volatile, thus high melting points • solids do not conduct electricity, but melts (liquid state) do • many, but not all, are water soluble Dr. S. M. Condren Ion Formation Dr. S. M. Condren Valance Charge on Ions • compounds have electrical neutrality • metals form positive monatomic ions • non-metals form negative monatomic ions Dr. S. M. Condren Valence of Metal Ions Monatomic Ions Group IA => +1 Group IIA => +2 Maximum positive valence equals Group A # Dr. S. M. Condren Valence of Non-Metal Ions Monatomic Ions Group VIA Group VIIA => -2 => -1 Maximum negative valence equals (8 - Group A #) Dr. S. M. Condren Charges of Some Important Ions Dr. S. M. Condren Polyatomic Ions • more than one atom joined together • have negative charge except for NH4+ and its relatives • negative charges range from -1 to -4 Dr. S. M. Condren Polyatomic Ions ammonium perchlorate cyanide hydroxide nitrate NH4+ ClO41CN1OH1NO31- sulfate carbonate phosphate Dr. S. M. Condren SO42CO32PO43- Names of Ionic Compounds 1. Name the metal first. If the metal has more than one oxidation state, the oxidation state is specified by Roman numerals in parentheses. 2. Then name the non-metal, changing the ending of the non-metal to -ide. Dr. S. M. Condren Nomenclature NaCl sodium chloride Fe2O3 iron(III) oxide N2O4 dinitrogen tetroxide KI potassium iodide Mg3N2 magnesium nitride SO3 sulfur trioxide Dr. S. M. Condren Nomenclature NH4NO3 ammonium nitrate KClO4 potassium perchlorate CaCO3 calcium carbonate NaOH sodium hydroxide Dr. S. M. Condren Nomenclature Drill Available for PCs: – on your disk to use at home or in the dorm – in the Chemistry Resource Center – off the web under Chapter 2, Links http://www.cbu.edu/~mcondren/c115lkbk.html Dr. S. M. Condren How many moles of ions are there per mole of Al2(SO4)3? 2, 3, 5 Dr. S. M. Condren Chemical Equation • reactants • products • coefficients reactants -----> products Dr. S. M. Condren Writing and Balancing Chemical Equations • Write a word equation. • Convert word equation into formula equation. • Balance the formula equation by the use of prefixes (coefficients) to balance the number of each type of atom on the reactant and product sides of the equation. Dr. S. M. Condren Example Hydrogen gas reacts with oxygen gas to produce water. Step 1. hydrogen + oxygen -----> water Step 2. H2 + O2 -----> H2O Step 3. 2 H2 + O2 -----> 2 H2O Dr. S. M. Condren Example Iron(III) oxide reacts with carbon monoxide to produce the iron oxide (Fe3O4) and carbon dioxide. iron(III) oxide + carbon monoxide -----> Fe3O4 + carbon dioxide Fe2O3 + CO -----> Fe3O4 + CO2 3 Fe2O3 + CO -----> 2 Fe3O4 + CO2 Dr. S. M. Condren