Chapter 2: Atoms & Molecules1. Elements: a substance that cannot be broken down to other substances by chemical reactions○ Essential Elements: Oxygen (O), Carbon ( C ), Hydrogen (H), Nitrogen (N), Calcium (Ca), Phosphorus (P), Potassium (K), Sulfur (S), Sodium (Na), Chlorine (Cl), and Magnesium (Mg).○ Trace Element: only needed in tiny amounts; Boron (B), Cobalt (Co), Copper (Cu), Fluorine (F), Iodine (I), Iron (Fe), Silicon (Si), and Zinc (Zn).2. Compound: a molecule that consist of two or more elements combined in a fixed ratio .. ex. NaCl and H2O3. Atom: the smallest unit of matter that still retains the chemical and physical properties of an element4. Chemical Bonds: attractions that hold molecules together○ Covalent Bonds: strong bonds, shared electrons■ Nonpolar Covalent Bonds: electrons will be shared equally■ Polar Covalent Bonds: electrons will not be shared equally○ Ionic Bonds: strong bond, transferred electrons■ when a cation, positively charged ion, and an anion, negatively charged ion, attract to each other■ result called ionic compounds, or salts○ Hydrogen Bonds: weak bond, important in DNA and proteins■ when a hydrogen atom covalently bonds to an electronegative atom5. Chemical Reactions: making and breaking chemical bonds; reactants make a change into a product [reactants→products]6. Energy Levels:○ 1st shell -- 2○ 2nd shell -- 8Chapter 3: WaterWater contributes to the fitness of the environment to support life. Cells are 70% to 95% water. Water’s various properties are the results of its structure and molecular interaction.1. Water is a polar molecule. It has opposite charges on opposite sides to allow maximum bonding, Water molecules are held together by hydrogen bonds.2. Water is cohesive. Water molecules stick to each other. Water has more structure than other liquids because so many of the water molecules are hydrogen bonded at one time. Cohesion helps water molecules travel up plant stems.3. Surface Tension: The measure of how difficult it is to break the surface of a liquid. Water has high surface tension and bonding.4. Adhesion: When water molecules cling to hydrophilic substances, like glass. Water molecules do not cling to hydrophobic substances, like wax. Adhesion aids in water movement in plants and animal tissues.5. Water stabilizes temperature. It resists temperature changes when it absorbs or releases heat, The oceans are huge heat sinks that help to regulate the earth’s temperature.6. Water is a versatile solvent: the dissolved substances are solutes.○ Hydrophilic substances are water soluble.○ Hydrophobic substances are NOT water soluble. This will be very important with the structure and function of the cell membrane.7. Acids, Bases, and pHpH is a measure of H ions or OH ions in a solution due to transfer between water molecules.○ If H = OH, it is a neutral solution○ If H > OH, it is an acidic solution○ If H < OH, it is a basic solution8. Buffers are substances that help to stabilize pH levels in living things. Body fluids need to have a pH of 6 to 8. Buffers helps to maintain that narrow pH range.○ A buffer can accept H ions when they are in excess or donate H ions when they have been depleted.○ Common buffer: bicarbonates (found in Tums, pepto bismol, and buffered
View Full Document
Unlocking...