LESSON 5.1

• Chemical reaction


  Molecules of the reactants come in contact with one another
• Chemical reaction


  1. Bonds between atoms are broken

  2. New bonds can form
• Activation energy


  Energy needed to break the bonds apart
• Energy lower than reactants


  Heat is given off, reaction is exothermic
• Energy of products higher than reactants


  Heat is absorbed, reaction is endothermic
• Fossil fuels


  Combustible materials that took millions of years to form underneath the earth
• Fossil fuels


  Also called convenience fuel
• Types of fossil fuels

  • Coal
  • Petroleum
  • Methane gas (natural gas)
• Fossil fuels


  • Extensively used due to their technical convenience and economy
• Biogas


  Produced by the anaerobic decomposition of organic materials by bacteria
• Biogas


  Combustible gas consisting mostly of inflammable hydrocarbon gas called methane
• Geothermal energy


  Heat obtained from underneath the earth and carried to the surface as steam
• Geothermal energy


  • Heat may be close enough to the surface manifested in volcanoes, geysers, hot springs, and boiling pools
• Hydroelectric energy


  Moving water is the source of energy
• Hydroelectric energy


  1. Moving and falling water is used to turn waterwheels

  2. Turning waterwheels were used to turn millstones
• Voltaic cells


  Undergo electrochemical processes to produce electrical energy
• Types of voltaic cells

  • Dry cells
  • Lead storage batteries
  • Fuel cells
• Photovoltaic cells


  Usually used for powering homes
• Solar energy


  Used directly from the sun
• Solar energy system


  Solar cells convert incoming radiant energy from the sun directly into electrical energy
• Biomass


  Formed from plant and animal materials
• Traditional form of biomass


  • Firewood
• Biomass


  Wood is burned directly to provide heat and energy
• Saponification


  Process in which triglycerides are combined with a strong base to form fatty acid metal salts during the soap-making process
• Today, soaps are prepared from oils and fats from vegetables and plants like coconut oil
• Saponification


  The process of making soap is called saponification
• Cleaning agents


  Substances which are usually liquids, powders, sprays, or granules
• Cleaning agents


  • Used to remove dirt, dust, stains, bad smells, and clutter on surfaces
  • Used for health purposes to remove offensive odors and kill bacteria
• Emulsions


  Colloidal dispersion of liquids in a liquid
• Emulsions


  • An emulsifying agent is needed for the formation of emulsion
  • Important for maintaining the stability of the emulsions
  • Oil and grease are not soluble in water but can form a colloidal dispersion
• Cosmetics


  Pharmaceutical products used for improving skin appearance and body odor
• Forms of cosmetics


  • Lotions
  • Creams
  • Powders
• Cosmetics


  • Used for cleansing, protecting, and moisturizing the skin
• Lanolin


  Extracted from the waxes obtained from wool, used in the manufacture of hand and face lotions to help retain water and soften the skin
• Deodorants


  Substances applied to the body to prevent bad odor caused by bacterial breakdown or perspiration
• Antiperspirants


  Affect odor as well as prevent sweating induced by the sweat glands
• Ingredients commonly used in personal care products

  • Phenols and phenol derivatives
  • Aliphatic alcohols
  • Ethyl acetate
  • Fragrant esters
  • Alpha hydroxyl acids