TAKS Review Objective 3 The student will demonstrate an understanding of the structures and properties of matter.

Physical or Chemical Property or Change Red rock Paper can burn Sharpen a pencil Rusting Na can react with H 2 0 Copper tarnishing Candle melting Candle burning Boiling point of H 2 O Dissolving C 6 H 12 O 6 in H 2 O Substance can react with another substance Substance forms new substances Substance’s form is altered ~ KEY ~ PP = physical property CP = chemical property PC = physical change CC = chemical change ~ KEY ~ PP = physical property CP = chemical property PC = physical change CC = chemical change PP CP CC PC PP CC PC CP CC CP PC

Do you know? Element is Compound is Mixture is a substance that cannot be broken down into simpler substances. two or more elements combined to form a new substance whose characteristics are different than the original elements. two or more substances that are not chemically combined and can be separated.

Common Elements & Compounds… He N C Ca Cl Si H 2 O CO 2 NaCl C 6 H 12 O 6 CO HCl Helium Nitrogen Carbon Calcium Chlorine Silicon Water Carbon Dioxide Sodium Chloride (salt) Sugar Carbon Monoxide Hydrochloric Acid

The Atom Charges… Electrons are negatively charged protons are positively charged Neutrons have no charge

Periodic Table Nitrogen Family Period 6 What is a row called?What is a column called? What do all members of a family have in common? What do all members of the Helium family have in common? *** Same # of outer e - ; same reactivity *** *** Noble gases; non-reactive ***

Chemical Reactions & Equations Hydrochloric Acid + Sodium Hydroxide  Sodium Chloride + Water HCl + NaOH  NaCl + H 2 O Is this equation balanced? H = 2 Cl = 1 Na = 1 O = 1 H = 2 Cl = 1 Na = 1 O = 1 YES, it is balanced.

Exothermic or Endothermic? H 2 SO 4 + C 6 H 12 O 6  C + CO 2 + SO 2 + heat NH 4 Cl + BaOH·(8H 2 O) + heat  NaOH + H 2 O + NH 4  Exothermic Endothermic Exothermic Endothermic Exothermic means to give off heat during the reaction Endothermic means to take in heat to run the reaction

Specific Heat Also know as heat capacity The amount of heat needed to raise the temperature of 1 g of a substance 1°C Substances with low specific heat will heat very quickly Substance with high specific heat values require larger amounts of heat to cause its temperature to raise the same amount

Which material will heat the fastest? Which material will stay hot the longest? Which material loses heat faster, liquid water or solid water?

Specific Heat We have land and sea breezes… …due to the differences in specific heat of the land and of the water. Water has a much higher specific heat which means it takes more energy to heat the water than the land. Since the land heats faster during the day, the breeze blows in from the sea and vice versa.

Question In the diagram, which cools off more quickly? A. the land B. the water C. neither D. not given

Question When a drain cleaner is added to a clogged sink, the drainpipe becomes warm to the touch. What type of chemical reaction is occurring to cause the pipe to become warm? Since heat is being given off as evidenced by the warming of the pipe, this chemical reaction must be exothermic.

Reminders… We balance equations because of the law of Conservation of Mass Know common element symbols including C, N, O, H, He, Na, Cl, Al, Si, & S Specific heat affects the world around us including weather Know that the atom is the smallest particle of a substance »Any questions???