CHEMICAL REACTIONS

• Combination reaction

  • two or more compounds combine to form one compound
  • A + B > AB
• Decomposition Reactions

  • the opposite of a combination reaction
  • complex molecules breaks down to simpler ones
  • AB > A + B
• Precipitation Reaction

  • two solutions of soluble salts are mixed resulting in an insoluble solid (precipitate) forming.
  • A + Soluble salt B > Precipitate + Soluble Salt C
• Neutralization Reaction

  • an acid and a base react with each other
  • product is always salt and water
  • Acid + Base > Salt + Water
• Combustion Reaction

  • oxygen combines with a compound to form CO2 and H2O
  • exothermic reaction : gives off heat
  • A + O2 > H2O + CO2
• Displacement Reaction

  • one element takes place with another element in the compound
  • A + BC > AC + B
• REDOX REACTIONS

  • Redox Reactions - involve the transfer of electrons between reactants leading to a change in oxidation states of the elements
  • in a redox reaction, one reactant loses electrons (is oxidized) while the other gains electrons (is reduced)
  • Reducing agent - species that is oxidized
  • Oxidizing agent - species that is reduced
• Factors that Increase Rates of Reactions

  • higher temperatures
  • higher concentration of reactants
  • larger surface area of reactants
  • addition of catalyst (substance that increases rate of reaction without consuming itself)
• Factors that Affect Solubility

  • temperature - e.g. milk dissolves in water
  • surface area of solute - e.g. sugar will dissolve faster than sugar cubes
  • pressure - e.g. carbon dioxide escapes from a soft drinks bottle when the bottle is opened due to a decrease in pressure