Test 2 Review

Test Format Part I: – Lab set up – Follow directions, answer question, apply information Part II: – Written/computer test – 31 questions – Multiple choice – See score right away

Vocabulary Chemical equation Reactant Product Conservation of mass Closed system Open system Photosynthesis Respiration Fire Rust Catalyst Endothermic Exothermic Precipitate Chemical change Physical change Chemical property Physical property Evaporation Freezing Boiling Flammability Dependent variable Independent variable

Chemical Equations Can you identify: Reactant + reactant  product + product product + product reactant + reactant

Practice 6 CO H 2 0  C 6 H 12 O O 2 carbon dioxide + water  sugar + oxygen Circle the reactants: Box the products: What is this equation?

Practice Fe + O2 + H2O  Rust 2Mg + O2  2MgO

Law of Conservation of Mass Total mass of reactants = Total mass of products 5g H20 + 5g O2 = _____ g 2H2O2 10g = 10g

Law of Conservation of Mass Same # of atoms on reactant side as the product side 2H 2 + O 2  2(H 2 O) H= ____H=____ O= ____O=____

Practice Mg + O 2  MgO Mg = ____Mg= ____O = _____ Oxygen Mg Oxygen

Is this balanced? 2 Mg + O 2  ___ MgO Mg = ____Mg= ____O = _____ NO

+   Produced a gas  (closed system)  (open system) 5g 85g ___ g 90 g <90 g

Photosynthesis 6 CO H 2 0  C 6 H 12 O O 2 carbon dioxide + water  sugar + oxygen Respiration C 6 H 12 O O 2  6 CO H ATP sugar + oxygen  carbon + water + energy dioxide

What influences the rate of a reaction (how fast it happens?) Crushing (size) Stirring (motion) Temperature Amount of solution Catalyst (substance that speeds up reaction)

Describing reactions Exothermic = ____________ Endothermic = _________________ Heat given off Heat taken in

How has understanding chemistry helped us? Inventions of new things Discovery of new elements Cooking Forming new items

Property or Change? Property = describes, characteristic What it has the ABILITY to do Change = actually changing

Property or Change? Boiling point of a chemical 2 different liquids mix  bubbles Food coloring in water Burning an egg It has a yellow color It produced a smell It melted Property Change

Physical or Chemical Physical = it looks different BUT the atoms are still the same you could reverse it Chemical = may or may not look different BUT the atoms are rearranged differently you CAN’T reverse it

PC or CC Tearing paper Burning paper Breaking wood Campfire Mixing kool aid Cooking a cake Freezing water Physical change Chemical change Physical change

PP Volume Density Freezes at 30 C Boiling point Can melt at room temperature Flexible Magnetic Bouncy Floats Solid, liquid, gas state of matter CP Flammable/non flammable Can rust Can tarnish Can burn Can react with water PC Breaking a stick Dissolving kool aid Food coloring in a liquid Cutting hair Bending metal Scrapping a crayon Melting chocolate Evaporated water CC Gas produced Light given off Odor produced Diet Coke + Mentos = Bubbles Baking Soda + Vinegar = colder Photosynthesis Respiration Rusting Leaves changing color