Chapter 3: Molecules, Compounds, and Chemical Equations
Chapter 3: Molecules, Compounds, and Chemical Equations Chem 105
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This 2 page Class Notes was uploaded by Hayley Masterson on Monday September 21, 2015. The Class Notes belongs to Chem 105 at Washington State University taught by Z Heiden in Summer 2015. Since its upload, it has received 38 views. For similar materials see Principles of Chemistry I in Chemistry at Washington State University.
Reviews for Chapter 3: Molecules, Compounds, and Chemical Equations
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Date Created: 09/21/15
Hayley Masterson September 1 2015 Chem Notes Chapter 3134 1 Hydrogen Oxygen and water a Hydrogen i Boiling point 253 degrees C Gas at room temp Explosive b Oxygen i Boiling point 183 degrees C Gas at room temp Necessary for combustion c Water i Boiling point 100 degrees C Liquid at room temp used to extinguish ames d When two or more elements combine to form a compound an entirely new substance results 2 Chemical Bonds a Compounds are atoms held together by chemical bonds b Result from attractions between charged particles c Two types of bonds i lonic bonds oppositely charged ions from a metal cation and nonmetal anion attract one another and form an ionic bond 1 The result in a solid phase forms a lattice threeD array of alternation cations and anions ii Covalent bonds When a nonmetal bonds with another nonmetal neither atom transfers its electron to the other Instead they share some of their electrons 1 Covalently bonded atoms form molecular compounds 2 The lowest potential energy most stable bond occurs when the negative charge lies between the two positive charges 3 Representing compounds chemical formulas and molecular models a Chemical formula indicates the elements present in the compound and the relative number of atoms or ions of each b Types of chemical formulas i Empirical formula gives the relative number of atoms of each element in a compound ie HO for hydrogen peroxide but H20 for water because no simple whole number representation exists ii Molecular formula Gives the actual number of atoms of each element in a molecule of a compound ie H202 for hydrogen peroxide iii Structural formula uses lines to represent covalent bonds and shows how atoms in a molecule are connected or bonded to each other c Molecular models i Ball and stick model represents atoms as alls and chemical bonds as sticks and how the two connect re ect the molecule39s shape ii Space lling molecular model atoms ll the space between each other to more closely represent our best estimates for how a molecule might appear if scaled to size 4 An atomic level view of elements and compounds a b Atomic elements exist in nature with single atoms as their basic units Molecular elements do not normally exist in nature with single atoms as their basic units instead they are molecules ie HOFlBrlNCI Hoff Brinkle or Hydrogen Oxygen Fluoride Bromine lodine Nitrogen Chlorine P S and Se selenium exist as polyatomic p4 58 Molecular compounds composed of two or more covalently bonded nonmetals lonic compounds composed of cations and anions metals and nonmetals bound together by ionic bonds Formula Unit the smallest electrically neutral collection of ions Polyatomic lon an ion composed of two or more atoms with the formula CLO ie MgCO2 Quiz one of Friday make notecard sec 3141 and 38 to 39 Chapter one Elements compounds mixtures Physical changes properties Conversions Sig gs Unit conversions Chapter two Protons electrons and neutrons for isotopes and ions Atomic mass from isotope abundance Grams to moles to atoms Chapter 3 lonic vs covalent compounds Formula and molar mass for compounds Mass percent