Transcript CHEMISTRY
CHEMISTRY For DUMMIES (you’re not dummies) This is just a dumb lecture. Chapter 2 What you were supposed to learn in ICS or Chemistry last year. Everything in the universe is made of matter. But what is MATTER? Nucleus contains: PROTON: (+) & 1 AMU NEUTRON: neutral & 1 AMU Outside the nucleus: ELECTRON: (-) & no AMU THE ATOM IS THE BASIC UNIT OF MATTER ATOM = The Dodger’s Stadium NUCLEUS = baseball (pencil eraser) on the pitcher’s mound (contains protons & electrons) ELECTRONS = seating… even nose-bleed seats The periodic table of elements shows all the types of matter known to man. ELEMENTS are pure substances that cannot be broken chemically into simpler kinds of matter. Each square shows the: chemical symbol, atomic number, & atomic mass. Ex. Carbon is C 6 12 Atomic # =‘s # of protons # of electrons Atomic mass = protons + neutrons Biology is cool because we don’t need to memorize all 100+ elements… we only need to be concerned with The 6 chemicals of LIFE… (What you need to live.) Carbon Hydrogen Nitrogen Oxygen Phosphorus Sulfur SUMMARY: • The ATOM is the smallest unit of matter. • All atoms are basically the same: 1. protons (+) & neutrons (no charge) IN NUCLEUS 2. electrons (-) OUTSIDE the NUCLEUS 3. NEUTRAL OVERALL (#p=#e) 4. When atoms gain or lose electrons they become IONS- they have a charge. Ex. a Hydrogen atom that loses it’s electron is called a hydrogen ion, H+, or a proton. CHEMISTRY IS THEbut STUDY OF Sort of like psychologyfor atoms. THE BEHAVIOR OF ATOMS… OF MATTER. 1. 2. 3. 4. 5. WHAT HAVE CHEMISTS LEARNED??? The nature of most atoms is that they are LONELY and sometimes AGGRESSIVE! Most atoms team up with or overtake other atoms in an attempt to get the “right” number of electrons. This is how molecules are formed. Only the NOBLE GASSES can exist on their own. ATOMS will switch partners when provoked. This is what chemical reactions are all about. Don’t mess with an atom’s nucleus. MATTER EXISTS IN DIFFERENT FORMS DEPENDING ON ITS OWN PERSONALITY AND ITS ENVIRONMENT. See above: States of Matter… Temperature can influence this. one column of elements is NONREACTIVE (noble gasses). The rest stick together through various Kinds of bonds… and so we Have “matter” that is big enough to see. COMPOUND ex. water, saltNaCl, glucose Pure substance that is made up of atoms of two or more elements. Water molecules MOLECULE Ex. oxygen (O2) Water, glucose, carbon dioxide etc. the simplest part of a substance that retains all the properties of the substance and that can exist in a free state. Oxygen gas is a molecule but not a Compound because it is only made from one kind of element… two oxygen atoms Are held together through a double bond. BONDING… 2 BASIC TYPES OF BONDS. COVALENT BOND Atoms share their electrons to reach the MAGIC NUMBER 2 or 8. Both hydrogens are sharing their one electron so both now have two. THIS IS HOW HYROGEN GAS EXISTS IN NATURE. 2 TYPES OF COVALENT BONDS: Nonpolar covalent bond- electrons are shared equally because both atoms have an equal pull on the electrons. Ex. Oxygen O=O or Hydrogen H-H Polar covalent bond- electrons are NOT shared equally because one atom is more electronegative than the other. Ex. Water H-O-H IONIC BOND Electrons are exchanged. Both become IONS Opposites attract! Ex. Chlorine STEALS an Electron from Sodium. Na+ Cl- Gaining an electron Makes the atom a Negative ion w/ a Charge of -1 (anion) Losing an electron Makes the atom A positive ion w/ a Charge of +1 (cation) GAIN OR LOSE ELECTRONS… CHEMICAL REACTIONS… what are they? • SIMPLY PUT… they are atoms switching groups or clique’s. • Bonds get broken. • Bonds are formed. • Rxns can release or require energy. Chem rxn for photosynthesis: 6CO2 + 6H20 + light C6H12O6 + 6O2 EXERGONIC Rxns RELEASE ENERGY ex. burning a candle or cell respiration ENDERGONIC Rxns. REQUIRE ENERGY ex. .Photosynthesis ACTIVATION ENERGY Amount of energy needed to start a spontaneous chemical reaction. HERE’S A REACTION WITH A HELPER… A CATALYST lowers the amount of activation energy needed to start a reaction . ENZYMES are biological catalyst. SOLUTIONS are easy to understand… • Solute = kool-aid • Solvent = water • Solution = drink Cell contents are solutions… so is your blood SOLVENT = water SOLUTES= glucose, ions like Cl-, Ca+, Na+, H+ Urea (cell waste), proteins, hormones The pH scale is a scale showing the relative amounts of (H+) Hydrogen and (OH-) Hydroxide ions in a solution. The pH of a solution will influence the shape of proteins in that solution