Unit 2 Chemistry of Life Chapter 2 and 3 Estimated Time: 5 Days Learning Goals: 1. Understand difference between Matter, compounds, Elements and Atoms 2. Know and explain importance of subatomic particles 3. Understand difference between different types of bonds and chemical interactions including hydrogen bonding and polarity of water 4. Understand four emergent properties of water (Hydrogen bonding, insulating factor, Moderation of local temperature, and acting as a solvent 5. Will be able to explain pH in terms of acids, bases and buffers Sodium + Chlorine Salt

Matter Review: - Matter is anything that takes up space - Elements are the purest form of matter - Compounds are made up of one or more elements -Atoms are the basic unit of elements that still retains all the properties of that element -Sub atomic particles Proton = (+) located in nucleus Electron = (-) located in orbitals (give atoms bonding properties) Nuetron = (=) located in nucleus

Atom Anatomy 2 He 4.00 Atomic Number (# of Protons) Symbol Atomic Mass (# of Nuetrons + # of Protons) -Electrons give elements bonding properties -Valence Electrons are outermost electrons -Electrons fill orbitals by: ( filling energy level, orbital, suborbital, and opposite spins) Chemical properties of elements depend on: -number of valence electrons -size of electron cloud -distance between outer shell and nucleus

Bonding and Chemical Attractions Atom to Atom Bonding -All bonds are based on an electric charge between atoms - One atom steals an electron from another = Ionic bonds -Atoms share electrons in their outer obritals (sp hybrids) = Covalent bonds -Polarity is when a molecule has a slight charge -Nonpolar has no net charge (No free electrons) Ionic Bonding Covalent Bonding Other weak bonds Used primarily in structures of macromolecules like DNA and Proteins 1. Hydrogen Bonds (Draw) 2. Non polar associations 3. Van der Waals Interactions 4. Sulfide Bridges

Water is boring! Or is it? There would be no life on earth if it wasn’t for the properties of water. Properties of water 1. Water is polar and repels nonpolar 2. Water forms hydrogen bonds 3. The solid form is less dense then the liquid form 4. High specific heat (amount of heat required to raise one gram one degree C.) 5. Is responsible for creating aqueous solutions

Emergent Property One: Cohesion -Hydrogen bonding is responsible for cohesion and adhesion -Cohesion = hydrogen bonds holding together the water molecules -Adhesion = hydrogen bonds holding water to another object -Surface Tension is an example of how cohesion works to hold the surface of a liquid together

Emergent Property Two: Moderation of Temperature -Specific heat of water is relatively high so it takes more heat to raise temperature of a body of water. -Specific heat of water plays a role in moderating ocean temperatures and other large bodies of water like the greaat lakes. -Water controls climate on nearby land masses as well as weather on all land Ex. Lake effect snow

Emergent Property Three: Water as an Insulator -Density of water gets higher has as it cools -Cooler, more dense, water holds more oxygen -Ice becomes less dense then the liquid form of water -Ice cover allows for aquatic life to survive winters -As the movement of molecules slow the hydrogen bonds become more stable in a lattice form

Emergent Property Four: Water as an Solvent -Hydrophilic substances like water or are polar -Hydrophobic substances don’t like water or are nonpolar -Water also is responsible for aqueous solutions -Water’s solvent properties are responsible for cellular organization or (Compartmentalization)

Water and pH Equilibrium Equation Potential Hydrogen -The pH scale is a logarithmic scale -Neutral pH is 7 or has a hydrogen concentration of An acid has a pH of less then 7 or < An base has a pH of greater then 7 or < pH = - log [H+] ex. 4 = -log [H+] [OH-] = ex. [10 -4 ] [ ] = [ ]