Chemical Reactions

Chemical ReactionsA _________ ___________is the process in which one or more substances change to make one or more new _________. The properties of the new substances differ from the original _____________.Examples: Leaves changing colors and muffins (pg. 292)

Signs of Chemical Reactions• Gas formations, solid formations, energy changes, odor change and

color changes are examples of ___________ _____________. • A precipitate is a solid that is produced as a result of a ________

__________ in a solution. • Exothermic reactions are chemicals reactions in which ________ is

released. • Endothermic reactions are chemical reactions in which _______ is

taken in. (Video #1 for class) Glow Sticks and Antacid • The starting material in a chemical reaction are called reactants.

Vinegar (CH3COOH) + Baking Soda (NaHCO3) are reactants

• The substances formed in a chemical reaction are called products. Ex: Vinegar (CH3C00H) + Baking soda (NaHC03) = (Sodium Acetate) CH3COONa + Carbonic Acid (H2CO3)

Chemical Formulas and Equations

• All substances are formed from about 100 ________. • Each element has its own ________ symbol. Ex: Hydrogen

= H, Gold = Au• Each element is made up of an ______ that is composed of

________, ________, and ________.• A chemical _________ is a shorthand way to use chemical

symbols and numbers to represent a ___________. Ex. H20 = Water

• A chemical formula shows how many ______ of each kind of element is present in a molecule. Ex. H20 has two atoms of hydrogen and one atom of oxygen

Chemical Formulas and Equations

• A subscript is a number written ______ and to the ______ of a chemical symbol in an equation. Ex: H20

• A coefficient is a number that is placed ____________ of a chemical symbol or formula. Ex. 2H

• A Chemical Equation uses chemical symbols and formulas as a shortcut to describe a chemical reaction. Ex: 2H2 + 02 = 2H20

Balancing Chemical Equations

• Law of Conservation of Mass – The law that states that mass is neither created nor destroyed. The total mass of the _________ is equal to the total mass of the __________. (Baking Soda, Vinegar, and Scale Experiment)

• Law of conservation of energy – The law that states that energy cannot be _________ or __________. Energy can change forms. Ex: Glowsticks, Battery, Campfire

Types of Chemical Reactions• Synthesis Reaction – A reaction where two or more substances

combine to form one new compound. Ex: Hydrogen and Oxygen combine to form water (pg. 304)

• Decomposition Reaction – A reaction in which a single compound breaks down into two or more simpler substances. Ex. Water is hit with an electric current and breaks down into Hydrogen and Oxygen (pg. 305)

• Single-displacement Reaction – A reaction where an element replaces another element that is part of a compound. Zinc plus Hydrochloric Acid produces Zinc Chloride and Hydrogen (Demonstration) Pg. 305

• Double-displacement Reaction – A reaction in which two compounds react and two new compounds form. One of the elements that make up the two compounds switch places (pg. 307) (Video 3)