Ch. 6-1: Atoms & Interactions Biochemistry Ch. 6-1: Atoms & Interactions

Properties of Matter Physical Properties Properties that do not change the chemical nature of matter Examples Color, Smell, Freezing Point, Boiling Point, Melting Point, Polarity, and Density Physical change – change in its state

Properties of Matter Chemical Properties Properties that DO change the chemical nature of matter Examples PH, Combustion, reactivity with water, explosions! Compounds put together that create a new compound

States of Matter Physical Changes Chemical Changes Change in appearance Solid, Liquid, Gas Chemical Changes Changes properties of matter all together Ex. Spoiling Milk

Properties of Chemical Change Forms or breaks chemical bonds Energy is taken (endothermic) or energy is released (exothermic) One or more new chemical substances are formed The process is usually difficult to reverse

Examples of Chemical Change Digestion Photosynthesis Respiration Burning Decomposition

Energy and Chemical Change Any energy an object has because of its position is called Potential energy. The energy in motion (actual) is called Kinetic energy.

Atoms: The building blocks of elements Atom - smallest particle of an element that has the characteristics of that element

Structure of Atoms Protons: Neutron: Electron: A particle located in the nucleus and has a positive charge Neutron: A particle located in the nucleus and has a neutral charge Electron: A particle located outside the nucleus and has a negative charge

Atoms An atom that has either gained or lost an electron is called an Ion Periodic Table Atomic Mass: how much it weighs Atomic Number: location on the periodic table (number of protons) Isotopes: variations in elements based on number of neutrons

How to Read the Periodic Table of Elements

Atoms Electrons circle the nucleus in Energy Levels Noble gases all have there outer most electron full of electrons.

2 e-’s inner and 8 e-’s middle and 1 e- in the outer

2 e-’s inner and 4 e-’s outer

Mass Number = Protons + Neutrons Ex. Carbon The atomic mass of carbon = 12 The atomic # of carbon = 6 = the # of protons - neutrons = Mass Number - protons - neutrons = 12 - 6 = 6

Ex: C12 : C 6 neutrons "normal" Isotopes of an Element Isotopes - atoms of the same element that have different numbers of neutrons. Ex: C12 : C 6 neutrons "normal" C 13 or C14 : C 7 or 8 neutrons isotope

Molecules Compound vs. Element An element is made up of atoms A compound is made up of different elements

Mixtures Solution Suspension Homogenous (same) mixture of components that stay mixed Sugar or Salt and water Suspension Mixture of two substances that may mix right away, but do NOT stay mixed up Starch and water

Mixtures Colloid A suspension of small particles that are dispersed into another substance Milk, foams Paint,

Medium / Phases Dispersed phase Gas Liquid Solid Continuous medium NONE (All gases are mutually miscible) Liquid aerosol Examples: fog, mist, hair sprays Solid aerosol Examples: smoke, cloud, air particulates Foam Example: whipped cream, Shaving cream Emulsion Examples: milk, mayonnaise, hand cream Sol Examples: pigmented ink, blood Solid foam Examples: aerogel, styrofoam, pumice Gel Examples: agar, gelatin, jelly, opal Solid sol Example: cranberry glass

Bonds Ionic Bond Sending an electron to an atom that is positively charged (opposing charges attract) EX. Na (+) = Cl (-) Salt H (+) = Cl (-) Hydrochloric Acid

Types of Bonds Cation- Anion – A positivily charged ion (more protons than electrons) Anion – Negatively charged ion that contains more electrons in its outer shell compared to the protons.

Bonds Covalent Bonds Sharing of electrons for the benefit of both EX.

Biochemistry Ch. 6-2: Water & Diffusion

Properties of Water Polarity of water Molecule with unequal distribution of charge. Allows for cohesion of other water molecules Allows water to dissolve many compounds Ions and polar molecules easily dissolve in water

Bonds Hydrogen Weaker bond It is the type of bonds that hold our DNA molecules together. Must include a Hydrogen molecule Causes water to expand when freezing

Properties of water Water Cohesion- Water molecules binding to other water molecules Hydrogen bonds attracted to each other and stick together! Ions and polar molecules easily dissolve in water. The water molecules surround and separate the solute being dissolved.

Movement of Molecules discovered by Brown Called “Brownian Motion”. Diffusion The net movement of molecule from an area of high concentration to an area of low concentration.