CHEMISTRY OF LIFE 1. Matter: a. All matter takes up space and has mass b. All living and nonliving matter are made up of elements c. Elements are pure and are naturally occurring * elements cannot be broken down into substances with different chemical or physical properties. 2. Six elements make up 98% of all living things C= Carbon, H=Hydrogen, N=Nitrogen, O=Oxygen P=Phosphorus, S=Sulfur 3. Compounds: 2 elements bonded together.

CHEMISTRY OF LIFE CON’T  Elements: Pure substance, only 1 kind of atom. Represented by a letter: O, N, P Or two letters: Mg, Cu, Li  Compound: Two elements bonded together. Ex: NaCl, H 2 O  Molecular Formula: Tells you how many atoms of each element in a molecule.  Structural Formula: graphical representation of the molecular structure, showing how the atoms are arranged

CHEMISTRY OF LIFE  Atoms: smallest unit of matter that cannot be broken down any further. a. Electrons: negative charge (e-) Outside b. Protons: Positive charge (p+) c. Neutrons: no charge (n) Inside the Nucleus Atomic Number=Number of protons Number of Protons=Number of Electrons

WHY BOND TOGETHER?  1. Arrangement of Electrons!  Grouped into different levels  Inner levels have more energy than outer levels.  Outer levels must have a certain number of electrons in it. If not, it is considered unstable and will react with other elements to help it have 8 in its outer shell becoming stable. (You will learn in chem that there are some levels that can hold more than 8. But for our purposes we are going to keep it at 8) E1= 2 E2= 8 E3 = 8

ELECTRON DOT EXAMPLE  Cl # of Protons= Atomic Number = 17 # of protons = # of electrons = 17 # neutrons = Atomic number – Atomic Mass = 18

TYPES OF BONDS  Covalent: When two or more atoms are shared between elements. Example H 2 O

IONIC BONDING  Ionic: When elements gain or lose electrons: creates a charge a. If lose an electron: positive charge b. If gain an electron: negatively charged c. This charge difference is what attacks the two elements

HYDROGEN BONDING  Attraction between a partial positive and partial negative charge molecule. Partial negative charge is oxygen, fluorine, or nitrogen and partial positive charge is hydrogen  Special bonding between water Link to animation of Hydrogen Bonding in Water - Northland Community and Technical College land.cc.mn.us/biology/Biology1111/animations/hydrogenbonds.html  Weaker than covalent and ionic bonds  Nonpolar: equal charge: do not like water  Polar: Unequal charge: water liking

WATER  Makes up nearly 70% of your body  Helps move nutrients and other substances into and out of your cells.  Stores heat efficiently: water helps us maintain homeostasis: Ex: humans sweat: water vapor lost through evaporation carries heat, cools body down.  Temperature falls more slowly protecting organisms from rapid temp. changes  Hydrogen bonds between water molecules require a large amount of heat to break

 Bonding 1. Cohesion: Attraction between same type of substances: a. surface tension: water can stretch without breaking easily 2. Adhesion: Attraction between different types of molecules a. Capillary Action: attraction of water to walls of tube sucks the water more strongly than gravity pulls it down. Water moving through stems. Cohesion of Water Adhesion of Water

NON-POLAR VS POLAR  Polar: water loving: 1. Substance attracted to water and will dissolve in water.  Non-Polar: Water hating 1. Substances not attracted to water and will not mix with it. ex: Oil: Non-polar molecules are pushed together forming beads or clumps in the water.

pH LEVELS: ACIDS AND BASES  Measures the amount of Hydrogen ions in a solution.  When the bonds in water break apart to a Hydrogen ion H+ and a hydroxide ion OH- H 2 O H+ + OH-  Scale: 0-6 Acid, 7 neutral, 8-14 Base  Acids : Increased Hydrogen ions H+  Bases: Decreased Hydrogen ions OH- (adding the oxygen decreases number of hydrogen ions. )

MIXTURES: 2 OR MORE SUBSTANCES ARE BLENDED TOGETHER BUT ARE NOT CHANGED CHEMICALLY. 1. Solutions a. One substance is completely dissolved into another substance b. Solute: Substance being dissolved c. Solvent: Substance dissolving the solute ex: Salt water 2. Suspensions: a. Particles spread through a liquid or gas, but settle out over time ex: sandy water 3. Colloids: a. Particles do not settle out, but stay suspended ex: Jello