* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 2 Matter and Components F11 110
Acid dissociation constant wikipedia , lookup
Electron configuration wikipedia , lookup
Gaseous signaling molecules wikipedia , lookup
Organic chemistry wikipedia , lookup
Atomic nucleus wikipedia , lookup
Coordination complex wikipedia , lookup
Biochemistry wikipedia , lookup
Nucleophilic acyl substitution wikipedia , lookup
Abundance of the chemical elements wikipedia , lookup
Isotopic labeling wikipedia , lookup
Inorganic chemistry wikipedia , lookup
Chemical bond wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Chemical element wikipedia , lookup
Rutherford backscattering spectrometry wikipedia , lookup
Condensed matter physics wikipedia , lookup
Acid–base reaction wikipedia , lookup
Gas chromatography–mass spectrometry wikipedia , lookup
Extended periodic table wikipedia , lookup
History of chemistry wikipedia , lookup
History of molecular theory wikipedia , lookup
Homoaromaticity wikipedia , lookup
Chemistry: A Volatile History wikipedia , lookup
State of matter wikipedia , lookup
Metalloprotein wikipedia , lookup
Atomic theory wikipedia , lookup
IUPAC nomenclature of inorganic chemistry 2005 wikipedia , lookup
9/4/11 Chapter 2: The Components of Matter 2.1 Elements, Compounds, and Mixtures: An Atomic Overview Chapter 2 2.2 The Observations That Led to an Atomic View of Matter 2.3 Dalton’s Atomic Theory 2.4 The Observations That Led to the Nuclear Atom Model The Components of Matter 2.5 The Atomic Theory Today 2.6 Elements: A First Look at the Periodic Table 2.7 Compounds: Introduction to Bonding 2.8 Compounds: Formulas, Names, and Masses 2.9 Classification of Mixtures Chap 2: Matter and Nomenclature 1 2 Chap 2: Matter and Nomenclature Definitions for Components of Matter Definitions for Components of Matter Element - the simplest type of substance with unique physical and chemical properties. An element consists of only one type of atom. It cannot be broken down into any simpler substances by physical or chemical means. Compound - a substance composed of two or more elements which are chemically combined. Mixture - a group of two or more elements and/or compounds that are physically intermingled. Chap 2: Matter and Nomenclature 3 4 Chap 2: Matter and Nomenclature Law of Mass Conservation The law of mass conservation. The total mass of substances does not change during a chemical reaction. The total mass of substances does not change during a chemical reaction. Chap 2: Matter and Nomenclature 5 reactant 1 + reactant 2 calcium oxide + carbon dioxide CaO + CO2 56.08 g + 44.01 g Chap 2: Matter and Nomenclature calcium carbonate (Words) CaCO3 (Symbols) 100.09 g (Quantities) 6 1 9/4/11 Law of Multiple Proportions Law of Definite (or Constant) Composition If elements A and B react to form two compounds, the different masses of B that combine with a fixed mass of A can be expressed as a ratio of small whole numbers. No matter the source, a particular compound is composed of the same elements in the same parts (fractions) by mass. Example: Carbon Oxides I & II Carbon Oxide I : 57.1% oxygen and 42.9% carbon Carbon Oxide II : 72.7% oxygen and 27.3% carbon Figure 2.2 Assume that you have 100 g of each compound. In 100 g of each compound: g O = 57.1 g for oxide I & 72.7 g for oxide II g C = 42.9 g for oxide I & 27.3 g for oxide II Carbon oxide II Carbon oxide I g O g C 57.1 = 42.9 g O = 1.33 g C 2.66 g O/g C in B = 7 72.7 27.3 = 2.66 2 1.33 g O/g C in A Chap 2: Matter and Nomenclature = 1 8 Chap 2: Matter and Nomenclature explains the mass laws The Postulates 1. All matter consists of atoms. Mass conservation postulate 1 2. Atoms of one element cannot be converted into atoms of another element. postulate 2 3. Atoms of an element are identical (in mass** and other properties) and are different from atoms of any other element. postulate 3 4. Compounds result from the chemical combination of a specific ratio of atoms of different elements. 9 Chap 2: Matter and Nomenclature explains the mass laws explains the mass laws Definite composition Multiple proportions postulate 3 postulate 3 postulate 1 postulate 4 Chap 2: Matter and Nomenclature 10 Chap 2: Matter and Nomenclature 11 Chap 2: Matter and Nomenclature 12 2 9/4/11 Millikan’s oil-drop experiment for measuring an electron’s charge. Experiments to determine the properties of cathode rays. Chap 2: Matter and Nomenclature 13 Rutherford’s α-scattering experiment and discovery of the atomic nucleus. Millikan used his findings to also calculate the mass of an electron. mass of electron = mass 14 Chap 2: Matter and Nomenclature determined by J.J. Thomson and others x charge charge = (-5.686 x 10-12 kg C ) (-1.602 x 10-19 C) = 9.109 x 10-31 kg = 9.109 x 10-28 g Chap 2: Matter and Nomenclature 1 in 20,000 15 16 Chap 2: Matter and Nomenclature General features of the atom today. Table 2.2 • The atom is an electrically neutral, spherical entity composed of a positively charged central nucleus surrounded by one or more negatively charged electrons. Properties of the Three Key Subatomic Particles Charge • The atomic nucleus consists of protons and neutrons. Name (Symbol) Relative Mass Absolute (C)* Relative (amu)† Absolute (g) Location in the Atom Proton (p+) 1+ +1.60218 x 10-19 1.00727 1.67262 x 10-24 Nucleus Neutron (n0) 0 0 1.00866 1.67493 x 10-24 Nucleus Electron (e-) 1- -1.60218 x 10-19 9.10939 x 10-28 Outside Nucleus 0.00054858 * The coulomb (C) is the SI unit of charge. † Chap 2: Matter and Nomenclature 17 The atomic mass unit (amu) equals 1.66054 x 10-24 g. Chap 2: Matter and Nomenclature 18 3 9/4/11 Atomic Symbols, Isotopes, Numbers A Z X Isotopes The Symbol of the Atom or Isotope X = atomic symbol of the element Isotopes are atoms of an element with the same number of protons, but a different number of neutrons. A = nuclide (or mass) number; A = Z + N Z = atomic number (the number of protons in the nucleus) Isotopes have the same atomic number, but a different mass number. N = number of neutrons in the nucleus Isotopes = atoms of an element with the same number of protons, but a different number of neutrons Chap 2: Matter and Nomenclature 19 Average Atomic Mass The Modern Reassessment of the Atomic Theory Since elements are found in nature as mixtures of isotopes, and each isotope is found in a fixed amount in nature, and rarely are these amounts equal among the given isotopes of an element we must have a way to take this into account when talking about a naturally occurring element; enter Average Mass: Ave Atomic Mass = ∑ 1. All matter is composed of atoms. The atom is the smallest body that retains the unique identity of the element. 2. Atoms of one element cannot be converted into atoms of another element in a chemical reaction. Elements can only be converted into other elements in nuclear reactions. ( fa Isotopei )(mass Isotopei ) 3. All atoms of an element have the same number of protons and electrons, which determines the chemical behavior of the element. Isotopes of an element differ in the number of neutrons, and thus in mass number. A sample of the element is treated as though its atoms have an average mass. for all isotopes fa = fractional abundance = 20 Chap 2: Matter and Nomenclature %Abundance isotope 100 4. Compounds are formed by the chemical combination of two or more elements in specific ratios. Chap 2: Matter and Nomenclature 21 22 Chap 2: Matter and Nomenclature Figure 2.10 Some metals, metalloids, and nonmetals Copper Cadmium Chromium Silicon Lead Bismuth Arsenic Chlorine Antimony Bromine Sulfur Iodine Carbon Boron Chap 2: Matter and Nomenclature 23 Tellurium Chap 2: Matter and Nomenclature (graphite) 24 4 9/4/11 Factors that influence the strength of ionic bonding. Transferring electrons from the atoms of one element to those of another results in an ionic compound. ECoulombic ∝ Chap 2: Matter and Nomenclature 25 Q1 × Q2 r12 Chap 2: Matter and Nomenclature 26 Formation of a covalent bond between two H atoms The relationship between ions formed and the nearest noble gas. Covalent bonds form when elements share electrons, which usually occurs between nonmetals. Chap 2: Matter and Nomenclature 27 Chap 2: Matter and Nomenclature 28 Elements that occur as molecules Molecules and Ions Molecule – the basic unit of an element or covalent compound, consisting of two or more atoms bonded by the sharing of electrons. Most covalent substances consist of molecules. Ion – a single atom or covalently bonded group of atoms that has an overall electrical charge. There are no molecules in an ionic compound. Have No Fear Of Ice Cold Beer Chap 2: Matter and Nomenclature 29 Chap 2: Matter and Nomenclature 30 5 9/4/11 The carbonate ion in calcium carbonate. Types of Chemical Formulas A chemical formula is comprised of element symbols and numerical subscripts that show the type and number of each atom present in the smallest unit of the substance. An empirical formula indicates the relative number of atoms of each element in the compound. It is the simplest type of formula. The empirical formula for hydrogen peroxide is HO. A molecular formula shows the actual number of atoms of each element in a molecule of the compound. The molecular formula for hydrogen peroxide is H2O2. A structural formula shows the number of atoms and the bonds between them, that is, the relative placement and connections of atoms in the molecule. A polyatomic ion consists of two of more atoms covalently bonded together and has an overall charge. The structural formula for hydrogen peroxide is H-O-O-H. In many reactions the polyatomic ion will remain together as a unit. Chap 2: Matter and Nomenclature 31 32 Chap 2: Matter and Nomenclature Nomenclature-History CauldronCast #1 • Early: Compounds named by those who discovered them; usually had some historic significance Nomenclature of Inorganic Compounds • Oil of Vitrol • Blue Vitrol • Laughing gas • Problem: No real system; region/researcher specific; needed systematic, well-defined nomenclature system • Answer: IUPAC development of standardized nomenclature schemes; some trivial names accepted and retained Naming Simple Inorganic Compounds Dr. Carl Hoeger profcah Chap 2: Matter and Nomenclature 33 Nomenclature-Basics 34 Chap 2: Matter and Nomenclature “Type I” Elements Two general classes of inorganic molecules: +1 1. Those containing a metal cation and a nonmetal anion OR a metal cation and a polyatomic anion (ionic compounds); 2. Those containing only nonmetals (molecular compounds; Type III compounds) +2 +3 +2 Two different types of the first class: a) Those whose metal has only one possible positive oxidation state (Type I compounds); b) Those whose metal has more than one possible positive oxidation state (Type II compounds) +1 The nomenclature scheme reflects the compounds class/type Chap 2: Matter and Nomenclature 35 Chap 2: Matter and Nomenclature 36 6 9/4/11 “Type II” Elements Chap 2: Matter and Nomenclature “Type III” Elements: Nonmetals 37 Chap 2: Matter and Nomenclature 38 Nomenclature: Cation Basics Nomenclature Periodic Table To name a cation (or the first element in a Type III compound): Type I: Use the name of the element; if you are talking about an ion by itself put ‘ion’ after the name: Na+ = sodium ion; Mg+2 = magnesium ion Special cations: NH4+ = ammonium ion; H3O+ = hydronium ion Type II: Use the name of the element AND its oxidation state (or charge); use roman numerals in parentheses to denote this; if you are talking about an ion by itself put ‘ion’ after the name: Cu+2 = copper (II) ion; Cr+6 = chromium (VI) ion Type III : Use the name; denote number of that element present using greek prefixes (more later) Chap 2: Matter and Nomenclature 39 40 Nomenclature: Polyatomic Anions Nomenclature: Anion Basics Learn these polyatomic anions NOW: To name a monatomic anion (OR the second element in a binary Type III compound): For ALL: Take the root name of the element and add -ide to the end: if you are talking about an ion by itself put ‘ion’ after the name: HCO3HSHSO4HSO3H2PO4ClO4ClO3ClO2ClOBrO3BrO2BrOIO4IO3C2H3O2- Cl- = chloride ion; S-2 = sulfide ion; P-3 = phosphide ion Type III Compounds ONLY: Add to the name of the second element a prefix denoting how many of that element there are: XO2 would be “X dioxide” POLYATOMIC ANIONS: These have their own nomenclature you need to know Chap 2: Matter and Nomenclature Chap 2: Matter and Nomenclature 41 Hydrogen carbonate Hydrogen sulfide Hydrogen sulfate Hydrogen sulfite Dihydrogen phosphate Perchlorate Chlorate Chlorite Hypochlorite Bromate Bromite Hypobromite Periodate Iodate Acetate NO3NO2OHMnO4CO3-2 SO4-2 SO3-2 C2O4-2 CrO4-2 Cr2O7-2 SCNCNHPO4-2 PO4-3 Nitrate Nitrite Hydroxide Permanganate Carbonate Sulfate Sulfite Oxalate Chromate Dichromate Thiocyanate Cyanide Hydrogen Phosphate Phosphate Chap 2: Matter and Nomenclature 42 7 9/4/11 Nomenclature: Polyatomic Anions Nomenclature: Oxyanions Learn these “-ate” polyatomic anions NOW: - HCO3 HSHSO4HSO3H2PO4ClO4ClO3ClO2ClOBrO3BrO2BrOIO4IO3C2H3O2- Hydrogen carbonate Hydrogen sulfide Hydrogen sulfate Hydrogen sulfite Dihydrogen phosphate Perchlorate Chlorate Chlorite Hypochlorite Bromate Bromite Hypobromite Periodate Iodate Acetate - NO3 NO2OHMnO4CO3-2 SO4-2 SO3-2 C2O4-2 CrO4-2 Cr2O7-2 SCNCNHPO4-2 PO4-3 Systematic nomenclature based on oxoacids of origin; End in -ate or -ite; may have per- or hypo- as prefixes; Learn name, formula, and charge of all -ate ions, then: Nitrate Nitrite Hydroxide Permanganate Carbonate Sulfate Sulfite Oxalate Chromate Dichromate Thiocyanate Cyanide Hydrogen Phosphate Phosphate a) If an ion has ONE LESS oxygen than the -ate ion, change -ate to -ite (charge does not change!); b) If an ion has TWO LESS oxygens than the -ate ion, change -ate to -ite and add hypo- as a prefix (charge does not change!); c) If an ion has ONE MORE oxygen than the -ate ion, add per- as a prefix (charge does not change!). 43 Chap 2: Matter and Nomenclature Nomenclature: Type I and II Compounds No. of O atoms Summary: Naming oxoanions Prefix Root Suffix per root ate ClO4- perchlorate root ate ClO3- chlorate root ite ClO2- chlorite root ite ClO- hypochlorite hypo Simple: take name of cation and anion and combine: CaCl2 = calcium chloride ZnS = zinc sulfide Ba3(PO4)2 = barium phosphate CrO3 = chromium (VI) oxide PbI4 = lead (IV) iodide Fe2O3 = iron (III) oxide Example Chap 2: Matter and Nomenclature 45 46 Chap 2: Matter and Nomenclature Determining cation charge for Type II ions Nomenclature: Type III Compounds • Based on knowing your anions and their charges! • A compound is neutral and has a charge of zero. • The sum of all the oxidation states in a compound must equal the overall charge on the ion or molecule. • Set up and solve for the unknown algebraically; so for Fe2O3: 1. START by naming as if it were a Type I compound: N2F4: nitrogen fluoride 2. THEN add a greek prefix to tell how MANY of each element there are: N2F4: dinitrogen tetrafluoride * Note: if there is only one of the first element, the prefix mono is NOT used: SO2 is sulfur dioxide NOT monosulfur dioxide ⎡⎣( # irons ) × ( charge of iron ) ⎤⎦ + ⎡⎣( # oxygens ) × ( charge of oxygen ) ⎤⎦ = charge of Fe 2O 3 ⎡⎣( 2x ) ⎤⎦ + ⎡⎣( 3( −2 )) ⎤⎦ = 0; solve to get x = +3 Chap 2: Matter and Nomenclature 44 Chap 2: Matter and Nomenclature 47 1 = mono 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa 7 = hepta 8 = octa 9 = nona 10 = deca Chap 2: Matter and Nomenclature 48 8 9/4/11 Nomenclature: Practice Nomenclature: Practice Try the following: Answers: C2O4 SeO4 Na2SO3 Al2Cr2O7 MgO Mo(CO3)2 MgO magnesium oxide CrO2 Rh(NO3)5 CrS2 chromium (IV) sulfide P5O10 H2O P5O10 pentaphosphorous decoxide AsO3 N2O AsO3 arsenic trioxide C2O4 dicarbon tetroxide Na2SO3 sodium sulfite Give yourself five minutes Chap 2: Matter and Nomenclature 49 50 Chap 2: Matter and Nomenclature Nomenclature: Practice Nomenclature: Exceptions (1) 1. Some compounds have been known and used for so long that their trivial (or common names) have become accepted by the IUPAC as official: Answers: SeO4 selenium tetroxide Al2Cr2O7 aluminum dichromate Mo(CO3)2 molybdenum (IV) carbonate H2O = water CH4 = methane PH3 = phosphine NH3 = ammonia SiH4 = silane N2H4 = hydrazine 2. Oxides of some nonmetals will sometimes be named as if they were Type II compounds: Rh(NO3)5 rhodium (V) nitrate H2O dihydrogen monoxide P2O5 = phosphorous (V) oxide; SeO3 = selenium (VI) oxide N2O dinitrogen monoxide Note: this is an older system that is slowly being phased out and we will not use Chap 2: Matter and Nomenclature 51 Table 2.4: Examples of Metals That Form More Than One Monatomic Ion* Nomenclature: Exceptions (2) 3. For Type II metals with only two common oxidation states an older, Latin system was once used; while it is not employed very often it is useful to know some simple rules regarding it. It is sometimes called the “-ous/-ic” system, where the LOWER charged cation will be denoted by the latin root name for that element plus -ous and the HIGHER charged cation will be denoted by the latin root name for that element plus -ic : Element Ion Formula Systematic Name Common Name Chromium Cr2+ Cr3+ Co2+ Co3+ Cu+ Cu2+ Fe2+ Fe3+ Pb2+ Pb4+ Hg22+ Hg2+ Sn2+ Sn4+ chromium(II) chromium(III) cobalt(II) cobalt(III) copper(I) copper(II) iron(II) iron(III) lead(II) lead(IV) mercury (I) mercury (II) tin(II) tin(IV) chromous chromic Cobalt Copper Iron Lead Fe2+ = ferrous ion/Fe3+ = ferric ion; Sn2+ = stannous ion/Sn4+ = stannic ion Not used much but still can be found being employed; important in lab! Mercury 4. Compounds containing hydrogen listed as the first element are acids and named differently, as are many carbon compounds. Tin *Listed Chap 2: Matter and Nomenclature 52 Chap 2: Matter and Nomenclature 53 cuprous cupric ferrous ferric plumbous plumbic mercurous mercuric stannous stannic alphabetically by metal name; the ions in boldface are most common. Chap 2: Matter and Nomenclature 54 9 9/4/11 Acid Nomenclature Binary Acid Nomenclature An acid is a compound that contains an acidic hydrogen (a H that ionizes in water) : For BINARY acids (HX(aq), where X does NOT contain oxygen; it MUST be in aqueous solution); Add hydro…ic acid to the root of the element X: Not all hydrogens are ionizable; by convention, to indicate when one IS, we begin the chemical formula with it: H2S(aq) = hydrosulfuric acid; HI(aq) = hydroiodic acid; HN3 (aq) = hydrazoic acid Note: if phase is NOT aqueous, name as if it were a Type I compound (even though they are considered to be molecular in nature): HC2H3O2 (acetic acid) has four hydrogens but only ONE is acidic (underlined for emphasis) There are two types of acids: binary and oxoacids Chap 2: Matter and Nomenclature H2S(g) = hydrogen sulfide; HI(g) = hydrogen iodide; HN3 (l) = hydrogen azide 55 Try the following: If the acid contains oxygen (HOX or HXOn) its name will be a function of the name of the anion portion (i.e. the portion remaining after all the acidic H’s have been removed: OX- or XOn-); so: – Determine the anion name; If the name ends in -ate, replace -ate with -ic acid If the name ends in -ite, replace -ite with -ous acid Leave prefixes alone; the root name is sometimes tweaked to aid in pronunciation H2SO4(aq) → anion is SO4-2 (sulfate) → acid name is sulfuric acid HClO(aq) → anion is ClO- (hypochlorite) → acid name is hypochlorous acid H2C2O4 HIO4 H2SO3 H2CO3 HCN HF H2CrO4 HC2H3O2 H3PO4 HNO3 H2Se HNO2 57 Acid Nomenclature: Practice Give yourself five minutes Chap 2: Matter and Nomenclature 58 Acid Nomenclature: Practice Answers: Answers: H2C2O4 oxalic acid HIO4 periodic acid H2SO3 sulfurous acid H2CO3 carbonic acid hydrocyanic acid HF hydrofluoric acid HCN 56 Acid Nomenclature: Practice Oxoacid Nomenclature Chap 2: Matter and Nomenclature Chap 2: Matter and Nomenclature H2CrO4 chromic acid HC2H3O2 acetic acid H3PO4 phosphoric acid HNO3 nitric acid H2Se hydroselenic acid HNO2 nitrous acid Chap 2: Matter and Nomenclature 59 Chap 2: Matter and Nomenclature 60 10 9/4/11 Basic Separation Techniques Mixtures Filtration: Separates components of a mixture based upon differences in particle size. Filtration usually involves separating a precipitate from solution. Heterogeneous mixtures: has one or more visible boundaries between the components (Sand in water; oil in water). Crystallization: Separation is based upon differences in solubility of components in a mixture. Homogeneous mixtures: has no visible boundaries because the components are mixed as individual atoms, ions, and molecules (Sugar in water; alcohol in water). Distillation: separation is based upon differences in volatility. Solutions: A homogeneous mixture is also called a solution. Solutions in water are called aqueous solutions, and are very important in chemistry. Although we normally think of solutions as liquids, they can exist in all three physical states. Extraction: Separation is based upon differences in solubility in different solvents (major material). Chromatography: Separation is based upon differences in solubility in a solvent versus a stationary phase. Chap 2: Matter and Nomenclature 61 Chap 2: Matter and Nomenclature 62 End Chapter 2 Chap 2: Matter and Nomenclature 63 11