HCC CHEM 161 - Molecules, Compounds, and Chemical Equations
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Chapter 3CompoundsSlide 3Slide 4Slide 5Molecular ElementsChemical BondsSlide 8Molecular ModelsSlide 10Molecular View of Elements and CompoundsClassifying Elements & CompoundsIonic vs. MolecularLearning CheckIonic CompoundsSlide 16Slide 17Naming Inorganic CompoundsIonic or MolecularPolyatomic IonsNaming Ionic CompoundsSlide 22Slide 23Slide 24Naming Molecular CompoundsSlide 26Nomenclature OverviewSlide 28Naming AcidsSlide 30Quantitative AspectMolar MassUsing Molar MassesPercent CompositionEmpirical FormulasSlide 36Molecular FormulasCombustion AnalysisSlide 39Chemical EquationsSlide 41Balancing an EquationSlide 43Slide 44Classifying Compounds Organic vs. InorganicModern Classifying Compounds Organic vs. InorganicCarbon BondingSlide 48Classifying Organic CompoundsSlide 50Names of AlkanesFunctional GroupsMolecules, Compounds, and Chemical EquationsCompoundsWhen two or more elements are combined chemically, they are called a compound.Just like letters of the alphabet can be combined to form an endless number of words, elements can be combined to form an endless number of compounds.Life would not possible without the diversity of compounds.CompoundsHydrogen, a diatomic and colorless gasOxygen, a diatomic and colorless gasWater, a clear liquid which is essential for most life formsCompoundsCompoundsMost elements are not found by themselves in nature, rather they occur in compounds like NaCl or MgOSome occur as diatomic molecules: N2 , O2 , F2 , Cl2 , Br2 , and I2.Others like P and S are polyatomic. Only the metals of Gold, Copper, and Silver can sometimes be found in their pure state.Molecular ElementsChemical BondsCompounds are held together by one of two types of bonds.Ionic bonds are the electrostatic attraction between cations and anions.Covalent bonds are when two atoms share at least a pair of electrons.CompoundsA chemical formula is used to describe our compounds.Uses subscripts after each element in the formula.Subscript of “1” is implied if no subscript.Empirical formula = simplest whole number ratio of the elements in compound.Molecular formula = actual number of atoms bonded together.Structural formula = shows how the atoms are bonded together with lines representing the bonds.Molecular ModelsA model may be used to represent a molecule.Ball-and-stickSpace-fillingNo model is completely accurate!Molecular View of Elements and CompoundsClassifying Elements & Compounds•Atomic elements = elements whose particles are single atoms•Molecular elements = elements whose particles are multi-atom molecules•Molecular compounds = compounds whose particles are molecules made of only nonmetals•Ionic compounds = compounds whose particles are cations and anionsIonic vs. MolecularPropane – contains individual C3H8 moleculesTable salt – containsan array of Na+ ionsand Cl- ionsLearning CheckClassifying each as either an Atomic element, Molecular element, Molecular compound, or Ionic compound.A) Formaldehyde, CH2OB) Red phosphorous, P4C) Cobalt, CoD) Magnesium chloride, MgCl2Ionic CompoundsIonic compounds – are substances that contain both cations and anions.Formulas are always empirical – lowest whole number ratio of cations and anions.Writing ionic formulas – charges must cancel to yield a neutral species. Most common charges for cations = +1, +2, or +3Most common charges for anions are -1, -2, or -3.Ionic CompoundsM , X +1 +2 +3-1 MX MX2MX3-2 M2X MX M2X3-3 M3X M3X2MXIonic CompoundsLearning CheckWrite the correct formula between the ions of…A) Ca and BrB) K and SC) Li and ND) Al and OE) Mg and PNaming Inorganic CompoundsChemical Nomenclature ‑ the systematic method of naming chemical compounds.Different system for naming Ionic and Molecular compounds.Ionic = cation (usually a metal) with an anion (usually a non-metal.Molecular = two or more non-metals or metalloid with a non-metal.Identify compound BEFORE going to the rules!!!Ionic or MolecularLearning Check…Identify as Ionic or MolecularA) Na2SB) PCl3C) SiH4D) FeBr3E) ZnOF) CCl4Polyatomic IonsAn ion composed of two or more elements with a net charge.Only one is a cation – NH4+ = ammonium ion.All the rest are anions.Any time a polyatomic ion is present, then the compound is ionic.Ex) Na2SO4, MgCO3, NH4ClWhen more than one polyatomic ion is needed to balance charges, then use (poly)x.Ex) Al(NO3)3, (NH4)2SNaming Ionic CompoundsTwo subcategories:Metals with only one valence (mostly the main group metals)Metals with more than one possible valence charge.Metals with only one valence1.Name the metal first2.Name the non-metal second and change its suffix to ide.For polyatomic ions, they ALWAYS keep their same name – DO NOT CHANGE TO id e ending.Learning CheckWhat is the name of…A) NaBrB) MgSO4C) K2SD) Li3PO4Naming Ionic CompoundsMetals with more than one valence1. Name metal first followed by its valence in Roman Numerals and in ( ). This means that you will have to figure out the charge for that metal based on what it is bonded to.2. Name the non-metal second and change the suffix to ide.As before, polyatomics remain the same.Learning CheckWhat is the name of…A) Cu2OB) Fe2S3C) Mn(NO3)2D) Co3(PO4)2Naming Molecular CompoundsRemember, these contain only non-metals or a metalloid with a non-metal.1. Name the first non-metal in the formula.2. Name the second non-metal in the formula and change the suffix to ide.3. Add prefixes for all subscripts - except if the first one is a “1”.1 = mono, 2 = di, 3 = tri, 4 = tetra, 5 = penta, and 6 = hexa.Learning CheckWhat is the name of…A) CS2B) PCl5C) AsBr3D) N2O4E) N2ONomenclature OverviewLearning CheckWhat is the name of…A) NiCl2B) K2CrO4C) Cl2OD) SF4E) (NH4)2SO4Naming AcidsAcids are molecular compounds that release an H+ when added to water.Formula starts with an “H”.Binary acids = H with one other element.Hydro + base name of non-metal + ic + acidHCl = hydrochloric acidOxoacids = HXOy Polyatomic ion ends in –ate, then suffix changes to –icPolyatomic ion ends in –ite, then suffix changes to -ousLearning CheckWhat is the name of…A) HBrB) HNO3C) H2SO3D) H3PO4Quantitative AspectA chemical formula also has a quantitative aspect.A Formula Weight for


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HCC CHEM 161 - Molecules, Compounds, and Chemical Equations

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