Chemistry of Life Chapter 2 Sections 1 & 2 (pg 27-33)

Vocabulary  Atom- The smallest unit of matter that can not be broken down by chemical means.  Element- A pure substance made of only one kind of atom.  Compound- A substance made of the joined atoms of 2 or more different elements  Molecule- Group of atoms held together by covalent bonds  Ion- An atom or molecule that has gained or lost one or more electrons

Vocabulary Cont.  Cohesion- Attraction between substances of the same kind  Adhesion- Attraction between different substance  Solution- A mixture in which one or more substances are evenly distributed in another substance  Acid- pH = Higher concentration of H + ions Lower concentration of OH - ions  Base- pH = Lower concentration of H + ions Higher concentration of OH - ions

pH Scale Standard of measurement of the concentration of hydrogen ions (H+) present in a solution. Range Acid 0-6.9Base Neutral 7 H + IonsOH - Ions

Atom  Proton Positive Charge  Neutron No Charge  Electron Negative Charge

Elements, Isotopes, Compounds  More than 100 elements  Isotopes- Atoms of an element that contain different numbers of neutrons Carbon 12, Carbon 13, Carbon 14  Sodium + Chloride = NaCl  NaCl is table salt!!  Hydrogen + Oxygen = H2O  H2O is water!!

Bonds  Chemical Bond A force that joins atoms  Covalent Bonds Form when 2 or more atoms SHARE electrons to form a molecule  Hydrogen Bonds A WEAK chemical attraction between polar molecules  Ionic Bond Ions of opposite charge interact

Water  70% of your body is made up of water  Water “Universal Solvent” Water is polar, it dissolves many polar molecules

Solutions  Solution A mixture in which one or more substances are evenly distributed in another substance Solute  What gets dissolved Solvent  What is doing the dissolving

Polar vs Nonpolar Molecules  Polar Molecules Unequal distribution of electrical charge Dissolve well in water  Ionic compounds and polar molecules dissolve best in water  Nonpolar Molecules Do not dissolve well in water  Example: Oil and Water Water is more attracted to itself than the oil

Acids & Bases  Acid Compounds that form hydrogen ions (H + ) when dissolved in water  Base/Alkaline Compounds that reduce the concentration of hydrogen ions (H + ) in a solution Form hydroxide ions (OH - ) when in water

Buffers  Buffers help maintain pH levels in living things Lemon + Household Ammonia  More OH - than H + ? Any base  Antacid  Hand Soap  Household Ammonia

States of Matter Some Characteristics of Gases, Liquids and Solids gasliquidsolid assumes the shape and volume of its container assumes the shape of the part of the container which it occupies retains a fixed volume and shape compressiblenot easily compressible flows easily does not flow easily

Lime Juice  Spencer and Veronica were having a lime eating contest. They decided to see who could eat the most limes in a minute without making the sour face. Spencer ate 12 limes while Veronica could only eat 4. A couple of hours later they both noticed that they had heartburn, which is a painful and burning sensation in the esophagus, just below the breastbone usually associated with regurgitation of gastric acid.esophagusbreastbonegastric acid Take an antiacid – Neutralize the acidic lime juices in their stomaches. pH around 2-3

Acidic, Basic (alkaline) or Neutral Hydrogen ions Hydroxide ions AcidBaseNeutral