U4: Chemical Processes

Signs of a chemical reaction

• release of gas → bubbles

• color change

• precipitate → cloudy, opaque solution

• energy/heat change

Chemical change

rearrangement of the ways the atoms are grouped

Reactants

Chemicals present before reaction

Products

Chemicals formed by reactions

Law of Conservation of Mass

• Atoms are neither created nor destroyed

• Atoms are conserved in chem reaction

Ionic compounds

• metals + nonmetals

• crystalline solids

• water + ionic = aqueous

Molecular compounds

• nonmetal + nonmetal

• usually gases, sometimes liquid

What is solubility chart used for?

To determine if ionic compound will:

• dissolve in water

• form precipitate in double replacement

What is activity series chart used for?

To tell if an element can replace another in reaction

Types of Chemical Reactions

• Double Replacement

• Acid-Base

• Oxidation-Reduction (Redox)

  • Synthesis

  • Decomposition

  • Single replace

  • Combustion

Double Replacement

• Forms precipitate

• Reactants: 2 soluble ionic compounds

Oxidation-Reducation (Redox) Reaction

• Reaction involves the transfer of electron

LEO says GER

Loss of Electrons is Oxidation

Gain of Electrons is Reduction

Single replacement reaction

• a reaction where 1 element takes place of another element as part of compound

  • Metal always replaces metal

  • Non-metal always replace non-metal

Synthesis

combo of 2+ substances to form a compound

Decomposition

• compound breaks down to form 2+ simpler substances

• opposite of synthesis

• accomplished via heating/electric current

Combustion

• Substances react w/ oxygen gas in exothermic reaction

Formula:

hydrocarbon + O₂ gas + CO₂ gas → water vapor + energy