Chemical Reactions Rxn Unit 5 Part 2 Chemical

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Chemical Reactions (Rxn) Unit 5 Part 2

Chemical Reactions (Rxn) Unit 5 Part 2

Chemical Rxns • When one or more substance changes into one or more NEW

Chemical Rxns • When one or more substance changes into one or more NEW substance. • Reactants (original substance) always on left Products (new substance) always on right

Example of chemical rxns:

Example of chemical rxns:

 • Chemical reactions are written as equations • Equations must be balanced because

• Chemical reactions are written as equations • Equations must be balanced because of the Law of Conservation of Matter • Matter can not be created nor destroyed in any chemical reaction

Chemical Symbols “ Yields” or “Produces”, used to separate the reactants from the products

Chemical Symbols “ Yields” or “Produces”, used to separate the reactants from the products + used to separate reactants and products from themselves Reversible Rxn (products can revert back) (s) or ( ) =solid state ( l ) =Liquid state (g) or ( ) =gaseous state (aq) = aqueous solution- a solid dissolved in a liquid heat is added catalysts- speed up Mn. O 2 chemical is added w/o changing the rxn

Indicators of Chem. Rxns • Release a gas (bubbles or smoke) • Changes COLOR

Indicators of Chem. Rxns • Release a gas (bubbles or smoke) • Changes COLOR • Change in energy (∆H) • Exothermic Rxn- Releases Energy – -∆H • Endothermic Rxn - Absorbs Energy +∆H • Formation of a Precipitate- • a solid that forms from 2 aqueous solutions

6 Types of Chemical Rxns • • • Combination/Synthesis Decomposition Single Replacement Double Replacement

6 Types of Chemical Rxns • • • Combination/Synthesis Decomposition Single Replacement Double Replacement Combustion Neutralization

Combination/ Synthesis • 2 or more reactants produce 1 product • A + X

Combination/ Synthesis • 2 or more reactants produce 1 product • A + X AX • A + X + Y AXY • Ex: Iron rusting • Fe + O 2 Fe. O 2 (rust)

Decomposition • 1 Reactant produces 2 or more products • AX A + X

Decomposition • 1 Reactant produces 2 or more products • AX A + X or AXY AX + Y • Ex: Decomposition • of water ELECTRICITY • H 2 O H 2 + 0 2

Single Replacement • Single element replaces another in a compound • AY + B

Single Replacement • Single element replaces another in a compound • AY + B BY + A Ex: Copper + Silver nitrate silver + copper (II) nitrate

Double Replacement • 2 Compounds react to form 2 new compounds • AX +

Double Replacement • 2 Compounds react to form 2 new compounds • AX + BY AY + BX • Ex: Pb(NO 3)2 + KI Pb. I 2 + KNO 3

Combustion • Hydrocarbon reacts with oxygen to produce carbon dioxide and water • Cx.

Combustion • Hydrocarbon reacts with oxygen to produce carbon dioxide and water • Cx. Hx + O 2 CO 2 + H 20 • Combustion reactions release ENERGY: light, heat, chemical energy (ex: ATP)

Types of Decomposition • Carbonates • Metal carbonate metal oxide + carbon dioxide •

Types of Decomposition • Carbonates • Metal carbonate metal oxide + carbon dioxide • Ex: Ca. CO 3(s) Ca. O (s) + CO 2 (g) • Hydroxides • Metal hydroxide metal oxide + water • Ex: Ca(OH)2 (s) Ca. O + H 2 O (g) • Chlorates • Metal chlorate metal chloride + oxygen • Ex: Na. Cl. O 3 Na. Cl + O 2 • Acids non-metal oxide + water • H 2 CO 3 (aq) CO 2 (g) + H 2 O (l)

Neutralization • Special type of double replacement between an acid & a base •

Neutralization • Special type of double replacement between an acid & a base • Acid + Base Water + Salt • Ex: HCl + Na. OH H 2 O + Na. Cl