CHEMICAL REACTIONS and SIGNALS

ELEMENTS (S) Using Textbk (pg 172-173) or Planner make flashcards for the following elements (spell accurately) and their chemical symbols (use correct format): hydrogen / helium / lithium / beryllium / boron / carbon / nitrogen / oxygen / fluorine / neon / sodium / magnesium / iron / nickel / cobalt / argon / copper / tin / zinc / silver / lead / bismuth / cadmium / gold / mercury / bromine / potassium / chlorine / phosphorus / iodine / tungsten / sulfur / uranium / vanadium / yttrium / calcium / silicon / gallium / aluminum / manganese / chromium / platinum / francium / arsenic / germanium / antimony / tellurium / astatine / polonium / xenon / radium / curium / thorium / barium / strontium / plutonium / nobelium / bohrium / krypton / radon / rubidium / cesium / ununoctium / indium / thallium / ununtrium / scandium / seaborgium / rutherfordium / mendelevium / meitnerium / lawrencium / dubnium / hassium / copernicium / actinium / lanthanum / zirconium / californium / europium / thulium / titanium / einsteinium / molybdenum / americium / berkelium / ytterbium / selenium / holmium / hafnium / ununseptium / livermorium / ununpentium / flerovium / praseodymium / niobium / tantalum / technetium / rhenium / ruthenium

CHEMICAL REACTIONS and SIGNALS:

(1) CHEMICAL REACTION  is the process in which ATOMS rearrange themselves to produce NEW substances (a) During a chemical reaction the BONDS that hold ATOMS together may be FORMED (e.g. “synthesis” chemical reaction) or BROKEN (e.g. “decomposition” chemical reaction) (b) PROPERTIES of the ORIGINAL substances (the reactants) are DIFFERENT than those of NEW substances (the product) produced during the CHEMICAL REACTION (1) a CHANGE in PROPERTIES is a SIGNAL that a CHEMICAL REACTION may have occurred

(2) SIGNALS indicating a CHEMICAL REACTION may have occurred:  COLOR change (silver [Ag]changes to BLACK and copper [Cu]changes to GREEN when it TARNISHES)  ODOR change (milk that has soured)  TEMPERATURE change (exothermic and endothermic reactions)  PRECIPITATE (SOLID substance forming in a solution of two LIQUIDS) forms

 GAS forms (vinegar [CH3COOH] REACTS with baking soda [NaHCO3])

(3) CHANGES in STATES of matter (due to MELTING, freezing or BOILING) are NOT due to a CHEMICAL change, but rather a PHYSICAL change (4) The ONLY sure evidence of a CHEMICAL REACTION is the formation of a NEW substance