logging in or signing up BIO 120 Chapter 2 Basic Chemistry (DHD Recorded) ddommer Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 280 Category: Education License: Some Rights Reserved Like it (0) Dislike it (0) Added: August 15, 2012 This Presentation is Public Favorites: 0 Presentation Description BIO 120 Chapter 2 Basic Chemistry (DHD Recorded) Comments Posting comment... Premium member Presentation Transcript Chapter 2: The Nature of Atoms: Chapter 2: The Nature of AtomsWhat composes Matter?: What composes Matter? Any substance that has mass and occupies space All matter is composed of AtomsWhat makes up an Atom??: What makes up an Atom?? In the nucleus Protons: Positively charged particles Neutrons: Neutrally charged particles Outside the nucleus Electrons: Negatively charged particles Orbit the nucleus in “orbitals” or “valence shells”Atomic Charges: Atomic ChargesMass vs. Weight: Mass vs. Weight Mass The amount of a substance Weight The force gravity exerts on a substanceAtomic Number vs Atomic Mass: Atomic Number vs Atomic Mass Atomic Number = Number of Protons Atomic Mass = Sum of the mass of protons + neutronsAtomic Mass: Atomic Mass Atomic Mass = Mass of all atomic particles Measured in daltons 602 million million billion (6.02 x 10 23 ) daltons = 1 gram 1 proton weighs (1.007) daltons 1 neutron weighs (1.009) daltons 1 electron weighs (1/1840) daltons Basically electrons are negligibleElements and Isotopes: Elements and Isotopes All atoms with the same atomic number are members of the same “element” Isotopes are atoms with different numbers of neutrons 12 6 Carbon 12 C 13 6 Carbon 13 C 14 6 Carbon 14 CAtomic Structure: Atomic Structure Neutral Atoms: Have the same number of electrons and protons (net charge =) Charged Atoms Cations: More protons than electrons (+) Anions: More electrons than protons (-)Electrons have potential: Electrons have potential The further away an electron is, the more potential energy it hasBohr Models of Atoms and Octet Rule: 11 Bohr Models of Atoms and Octet Rule electron electron shell nucleus hydrogen 1 1 H oxygen 1 6 8 O carbon 1 2 6 C nitrogen 1 4 7 N sulfur S 32 16 phosphorus P 31 15 H P S C O NFLUORESCENCE – NECTAR GUIDES : FLUORESCENCE – NECTAR GUIDESA word you’ll get sick of: Redox: A word you’ll get sick of: RedoxPeriodic table of elements + Life!: Periodic table of elements + Life! Periods = Rows (O,F,Ne,Na) Groups = Columns (Reactivity)Organic Macromolecules: Organic Macromolecules 12 out of 90 elements account for 99.9% of elements in living things 4 out of those 12 comprise 96.3% of living things (C,H,O,N) Cl CHOPKINS CaFe MgAtomic Bombs errr Bonds err bonds: Atomic Bombs errr Bonds err bondsMolecules vs Compounds: Molecules vs Compounds Molecules = group of atoms Compunds = molecules of more than one element one molecule indicates 6 atoms of carbon indicates 6 atoms of oxygen indicates 12 atoms of hydrogenMOLECULES AND COMPOUNDS: MOLECULES AND COMPOUNDS Compound - when atoms of two or more different elements bond together CO 2 , H 2 O, C 6 H 12 O 6 , etc. Characteristics dramatically different from constituent elements Molecule and compound can be used interchangeably In Biology molecule is used e.g. molecule of water (H 2 O) molecule of glucose (C 6 H 12 O 6 ) Bonds that exist between atoms in molecules contain energyYou gotta diversify ya bonds!: You gotta diversify ya bonds! Covalent - The sharing of one or more electron pairs between nuclei (80 kcal/mol) (H 2 0) Hydrogen – When a hydrogen atom is shared between two molecules (5 kcal/mol) Ionic – The transfer of one or more electron pairs from a metal to a nonmetal ( NaCl ) (4–7 kcal/mol) Electrostatic – Electrostatic charge induced by oppositely charged ions (Like COO - and NH 3 + ) (< 1 kcal/mol) Van der Waals – Short range attractive forces between chemical groups (< 1 kcal/mol)Ionic Bonds: Opposites attract Metal to Non-Metal: Ionic Bonds: Opposites attract Metal to Non-MetalCovalent Bonds: Covalent Bonds Molecule formed by sharing electrons between two atoms No net charge Octet rule is satisfied No unpaired electronsHow do we muck with bonds?: How do we muck with bonds? Temperature Physical Excitation Concentration of reactants and products Catalysts (more later)More Bonds: More Bonds Electronegativity is an atom’s affinity for electrons. Differences in electronegativity dictate how electrons are distributed in covalent bonds. Nonpolar covalent bonds = equal sharing of electrons Polar covalent bonds : unequal sharing of electronsReactions and Products: Reactions and Products Chemical reactions are written with the reactants first, followed by the products. 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 reactants products Photosynthesis Chemical reactions are often reversible. C 6 H 12 O 6 + 6O 2 6H 2 O + 6CO 2 Oxidative RespirationWater, damn that’s good: Water, damn that’s good ¾ of the Earth’s surface is water Life evolved in water 2 Billion years before moving onto land 2/3 of almost ALL organisms are comprised of waterChemical nature of water: Chemical nature of water Most important aspect of water – hydrogen bonding Only 5 – 10% of the strength of covalent bonds Simple molecular structureWhy are hydrogen bonds so cool?: Why are hydrogen bonds so cool? Hydrogen bonds are weak attractions between the partially negative oxygen of one water molecule and the partially positive hydrogen of a different water molecule. Responsible for most of the amazing properties of waterAmazing properties of water: Amazing properties of water Cohesion Adhesion High specific heat High heat of vaporization Less dense as a solid Solvent Properties Organizes nonpolar molecules IonizationCohesion: CohesionCohesion: CohesionHydrophilidae : HydrophilidaeAdhesion: AdhesionHigh Specific Heat: High Specific Heat Specific heat = amount of heat required by 1 gram of a substance to change it’s temperature 1 º C. What does a high specific heat mean? Why is this an interesting property of water?High Specific Heat: High Specific HeatHigh heat of vaporization: High heat of vaporization Heat of vaporization = amount of energy required to convert 1 gram of a liquid into a gas 586 calories for water What is the advantage?Water is less dense as a solid: Water is less dense as a solid Density = Mass / Volume Density of liquid water = 62.4 lbs / ft 3Density of water: Density of water Density = Mass / Volume PV = nrT As temperature decreases pressure or volume must decrease Can’t change atmospheric pressure Ice forms by EXPANSION, hence Volume INCREASES As Volume INCREASES, what happens to density? Sniggity SnackWater is the universal solvent: Water is the universal solventHeat Content of Water at Various Temperatures: Heat Content of Water at Various Temperatures freezing occurs evaporation occurs a. Calories lost when 1 g of liquid water freezes and calories required when 1 g of liquid water evaporates. Gas Liquid Solid 0 20 40 80 60 100 120 600 800 80 calories Temperature ( °C) Calories of Heat Energy / g 540 calories 400 200 0Homeostasis: HomeostasisWater can form ions: Water can form ions Hydroxide Ion: OH- Hydrogen Ion: H+ Since Hydrogen is only one proton and one electron a hydrogen ion is also called a protonpH: pH pH is the measure of the concentration of hydrogen ions (H+) in solution. The pH scale ranges in from 0-14. pH of a solution = -log[H+]pH: pH Logarithmic Scale Change in 1 unit represents a 10 fold increase in strength! Other log scales Light Richter Scale Acid of pH 3 is 100 times stronger than a pH of 5pH: pH Why does sugar rot your teeth? Bacteria + Sugar = Lactic Acid Saliva neutralizes acid, but the more sugar you have, the longer it takes Breathalyzer Dichromate (Orange) reacts with alcohol + CO 2 Forms Acetic Acid -> changes chromate ions Cr +3 (Green)Acids and Bases: Acids and Bases Acids either donate H+ to a solution or remove OH- from a solution Hydrochloric Acid H+ Cl- Bases then donate OH- to a solution (hydroxide) Sodium Hydroxide Na+ Oh- Strength is determined by ionization rates The more pure an acid or base is (the less water it contains) the faster the ionization rateBuffers: Buffers Resist change in pH by acting as a hydrogen ion donor or hydroxide ion acceptorBuffers: Buffers You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.