Alexander Crumpton Fuqua Chemistry Review Alexander Crumpton Fuqua

Found on the periodic table Elements Pure substances Found on the periodic table Na, Li, Be, B, Fe, Au, etc… Compounds Pure substance Chemically bound Separate through chemical reactions 2 or more elements H20, NaCl, CO2, Fe2O3 Mixtures 2 or more substances Physically combined Easily separated Filter, evaporate, sift

Types of Mixtures Homogeneous Mixture Heterogeneous Mixture Also called a solution Can not see the different parts Evenly mixed Air, steel, bronze, saltwater Heterogeneous Mixture Can identify all the parts mixed in Salad, Trail mix, granite, sand, Italian dressing, chicken soup

Metalloids Sit on the staircase Semi-conductors Share characteristics Metals Magnetic Shiny/luster Reactive Malleable Left of the staircase Ductile Good conductors of heat and electricity Non-Metals Dull Brittle Right of the stair case Poor Conductors Reactive with others Metalloids Sit on the staircase Semi-conductors Share characteristics

Periodic Table Arranged according to increasing atomic number Group 1: Alkali Metals Most reactive metals Group 2: Alkaline Earth Metals Reactive metals, but less than group 1 Group 3-12: Transition Elements Most varied properties Most familiar elements Group 17: Halogens Most reactive NON-METAL Group 18: Noble Gases/Inert Gases Least/Non-reactive group of elements Found in elemental form in nature Bonding Families USUALLY Group 1  Group 17 Group 2 Group 16 Group 13 Group 15 Group 14 Group 14 Groups/Families Share Characteristics 1-92 Natural Elements 93 or higher- Synthetic Elements

Chemical vs. Physical Properties Chemical Properties Can only observe by changing the object to something else, a new kind of matter Reacting with oxygen Burning Rusting Apple turning brown Reacting with Acids Physical Properties Can be observed WITHOUT making it something NEW Can observe with the 5 Senses Shape Density Solubility Odor Melting Point Boiling Point Color

Chemical vs. Physical Change Chemical Change New substance is created Properties different from original How you know a change has occurred: Color change Temperature change Formation of a precipitate Formation of a gas Physical Change Change in size, shape or form No new substance is created

Endothermic vs. Exothermic Reactions Endothermic Reactions: Takes in energy (heat) Examples: Melting Evaporating Cooking Exothermic Reactions: Gives off energy (heat) to the surroundings Examples: Combustion Composting Candle Flame

Law of Conservation of Matter (Mass) Matter is not created or destroyed in ordinary chemical and physical changes Open System Matter is lost to the surrounding environment i.e. mixing baking soda and peroxide in an open beaker, allowing gas to escape… Closed System Matter is not lost to the surrounding environments i.e. catching the smoke and ashes to measure out the final weight of the products…

Balancing Equations 2 H2O  2 H2O + 1 O2 Write out Elements in equations Count # of atoms present Start at the left, change coefficients (NEVER SUBSCRIPTS) in order to balance Continue balancing from left to right 2 H2O  2 H2O + 1 O2

Some Chemical reactions occur in more than one step Some Chemical reactions occur in more than one step. A 2 step reaction is shown Step 1: 2 PO2  PO3 + PO 30 grams x grams 7.62 grams Assuming all PO3 produced in step 1 completely reacts in step 2, approximately how many grams of CO2 are produced in step 2? Step 2: PO3 + CO  PO2 + CO x grams 5.09 grams 10 grams y grams

Some Chemical reactions occur in more than one step Some Chemical reactions occur in more than one step. A 2 step reaction is shown Step 1: 2 PO2  PO3 + PO 10 grams x grams 4.83 grams Assuming all PO3 produced in step 1 completely reacts in step 2, approximately how many grams of CO2 are produced in step 2? Step 2: PO3 + CO  PO2 + CO x grams 7.29 grams 5 grams y grams