SCI 4THQUARTER

• Chemical Reaction

  • Takes place when new substances are formed
  • Is a process in which the law of conservation of mass applies
  • During a chemical reaction, atoms are rearranged
• Collision Theory


  1. Particles of reactants must collide with one another

  2. Colliding particles must have sufficient energy
• Collision Theory


  • Explains how a chemical reaction takes place
• Evidences of Chemical Reactions

  • Production of light
  • Evolution of gas
  • Temperature change
  • Change in intrinsic properties (color, odor)
  • Formation of precipitate
• Chemical equation


  • Chemist's shorthand for a chemical reaction
  • Distinguishes between reactants and products
• Reactants


  The starting materials; substances that are used up to form new substances in a chemical reaction
• Products


  The resulting (new) substance/s
• Chemical equation shows the symbols or formulas of the reactants and products, the phases (solid, liquid, gas) of these substances, and the ratio of the substances as they react

  
• Types of Chemical Reactions

  • Combination (Synthesis) Reaction
  • Decomposition Reaction
  • Single Displacement (Replacement) Reaction
  • Double Displacement (Metathesis) Reaction
  • Combustion (Burning) Reaction
  • Acid-Base Reaction
• Combination (Synthesis) Reaction


  2 or more reactants combine to form a single product
• Decomposition Reaction


  A single reactant breaks down into simpler ones (2 or more products)
• Single Displacement (Replacement) Reaction


  One element replaces another element from a compound. The more active element takes the place of the less active element in a compound.
• Double Displacement (Metathesis) Reaction


  The positive ions (cations) and negative ions (anions) of different compounds switch places, forming two entirely different compounds.
• Combustion (Burning) Reaction


  Oxygen combines with a hydrocarbon (compound containing hydrogen and carbon) to form water and carbon dioxide.
• Acid-Base Reaction


  A special kind of double displacement reaction that takes place when an acid and base react with each other. The H+ of the acid reacts with the OH- of the base forming water and salt.
• In a combination reaction, two simple substances combine to from a single product.
• In a decomposition reaction, a compound breaks down into two or more simpler substances.
• In a single-replacement reaction, one element takes the place of another similar element in a compound.
• In a double-replacement reaction, two ionic compounds react by exchanging cation-anion partners. A double-replacement reaction generally produces an ionic precipitate, a gas, or a molecular compound.
• In a combustion reaction, a substance reacts with oxygen gas, giving off energy as light and heat.