Chemical Reactions

Chemical Reactions New substances being created due to bonds between atoms breaking, and/or the atoms bonding in new combinations The new substances will have new properties that are different from the properties of the original substances

Signs of a Chemical Reaction A spontaneous color change An odor is produced Energy change (temperature rises/falls, light is produced, a sound is produced) A gas is released A precipitate (solid) is produced ***Not all signs happen in each reaction***

Chemical Equations A shortened way to show the reaction that is taking place Equations use formulas to represent the reactants (what enters into the reaction) and the products (the results of the reaction) An arrow in the middle means a change has occurred (means “yields”)

Chemical Equations (con’t) 2 H2O 2 H2 + O2 Reactants Products Whatever elements start a reaction will be present at the end of a reaction, but in a different form/arrangement

Aluminum (Al) and Copper Chloride (CuCl2) solution Al + CuCl2  AlCl + Cu Aluminum + Copper Chloride  Aluminum Chloride + Copper

Sodium Bicarbonate (NaHCO3) and Calcium Chloride (CaCl2) (with water and BTB) White granules + white powder  white powder + white crystal + clear liquid + colorless gas Why does it turn from blue to yellow? BTB is an INDICATOR (a chemical that changes color to indicate the presence of another chemical) It changes from blue to yellow when carbon dioxide is present

Sodium Bicarbonate (NaHCO3) and Acetic Acid (CH3COOH) NaHCO3 + CH3COOH  NaC2H3O2 + H2O + CO2 Sodium Bicarbonate + Acetic Acid  Sodium Acetate + water + carbon dioxide

Sodium Chloride (NaCl) and Water (H2O) NaCl + H2O  NaCl + H2O salt + water  salt water solution

Homework Complete a 4 square vocabulary box for each of the following words: Reactant Product