STAR 8 th Grade Chemistry Review

Atom Structure 6 C Carbon 12 P N Nucleus Atomic # = Protons = Electrons Atom mass = Atomic# (protons) + Neutrons Atomic Number Symbol Name Atomic Mass Protons = + Electrons = - Neutrons = Neutral Isotope are caused by a change in neutrons E

Phases GAS Quickly moving Molecules Liquid Slow moving molecules Solid Vibrating molecules Boiling Condensation Melting Freezing Changes of Water solid melting liquid boiling gas Minutes Temperature

Reactions Chemical change Physical Change ripping boiling blending melting freezing solutions mixtures Chemical Change Color change Energy (heat) Precipitate Change in properties Gas production Compound Reaction energy Na + Cl Na Cl Solid Gas Salt Metal Energy Conservation of Mass Reactant = product No mass is lost Oxide = 1 oxygen Monoxide = 1 oxygen Dioxide = 2 oxygen Balance Equations 2Mg + O 2 → 2MgO Endothermic Enter Absorbs heat Exothermic Exit Releases heat

Living Chemistry Carbon is in all living organism Commonly in organisms *hydrogen * oxygen * nitrogen * sulfur * phosphorus Large Carbon Molecules Ring of carbonsChain of carbons Branch of carbon

Periodic Table

Noble Gases

Rows = period, valance electron Columns = group or family, similar characteristics Metals= shiny, malleable, ductile, conductor, and magnetic. Nonmetal= opposite characteristics of metals. Metalloids= “Wanna be metals” Periodic Table

Density D= M/V Lighter than = Floats Heavier than = sinks Volume 8cm³= V L X W X H = V Mass →triple balance → 32 g D= M/V = 32/8 = g/cm³ Volume with a cylinder Mass →triple balance → 3 g D= M/V = 3/5 2cm After Difference = 5 = Volume Before

Acids and Bases Acids Neutral Base Bases are bitter and slippery ; reacts with red litmus turning it blue. Acids are sour and squeaky; reacts with blue litmus turning it red.