GENERAL CHEMISTRY II

• All chemical reactions involve energy changes
• Energy Transformation

  • The capacity to do work
  • In chemical reaction, energy is converted from one form to another
• Heat


  The transfer of energy from a body of higher temperature to a body of lower temperature

  
• Thermochemistry


  The study of heat changes in chemical reactions
• When you stand near the burning wood, you can feel the hot surrounding

  
• Law of Conservation of Energy

  • It governs all transformations of energy
  • The combined amount of matter and energy in the universe is always constant
• Photosynthesis

  Plants convert energy harnessed from the sun to chemical energy
• Types of Energy

  • Mechanical energy
  • Chemical energy
  • Electromagnetic
  • Sound
  • Nuclear
  • Electrical
• Mechanical Energy


  The sum of all potential energy and kinetic energy of a system
• Potential Energy

  Energy possessed by a system by its position and composition
• Kinetic Energy


  The energy associated with motion
• Mechanical energy is the sum of all potential energy and kinetic energy of a system
• Considering all factors are kept constant


  A 5-kg ball will have higher kinetic energy than a 1-kg ball
• Chemical Energy


  • A form of energy stored within the structural units of a chemical substance, usually in the chemical bonds
  • A type of potential energy
• Batteries and Explosives are present in chemical energy
• Other Forms of Energy (ESGNE)


  • Electromagnetic energy
  • Sound energy
  • Gravitational energy
  • Nuclear energy
  • Electrical energy
• Batteries

  it has stored chemical energy
• Lightning

  provides electrical energy
• Label the heat transfer processes

  A) convection

  B) conduction

  C) radiation

  
• Law of Conservation of Energy

  ● It governs all transformations of energy.

  ● The combined amount of matter and energy in the

  universe is always constant.
• Law of conservation of energy

  
  

  Governs all transformation of energy
• Enumerate the other types of energy

  Mechanical, Chemical, Electromagnetic, Sound, Nuclear, Electrical
• Enumerate the types of energy (MCESNE)

  Mechanical, Chemical, Electromagnetic, Sound, Nuclear, Electrical
• Heat Capacity (C)

  the amount of energy needed to change the

  temperature of a given substance
• System

  The specific portion of matter we are interested in
• Surroundings

  Everything in the universe except the system
• Given the following systems/processes, what types of

  energy may be associated with these processes?

  (CHOICES : mechanical, chemical, thermal, gravitational, nuclear, solar, electrical energy)

  1. batteries - chemical energy
  2. burning of coal - thermal energy
  3. dynamite (an explosive) - chemical energy
  4. sunlight - solar energy
  5. lightning - electrical energy
  6. powerplants - nuclear energy
  7. em spectrum - electromagnetic energy
• fill the box :

  A) mechanical

  B) electrical

  C) thermal

  
• fill the box :

  A) electrical

  B) radiant

  C) thermal

  
• fill the box :

  A) nuclear

  B) thermal

  C) chemical

  
• Law of Conservation of Energy

  ● The total energy of the universe is conserved.

  ● two important concepts in thermochemistry: system

  and surroundings
• Boundary

  separates the system and the surroundings
• name the parts

  A) surrounding

  B) surrounding

  C) system

  D) boundary

  
• Heat

  • the thermal energy transferred between two systems

  at different temperatures that interact with one

  another

  • a process quantity
• Unit for heat (J)

  the unit for heat is Joules (J)
• Temperature

  the measure of the average kinetic energy of atoms or

  molecules in the system
• Specific Heat Capacity (c)

  ● the amount of energy needed to raise

  the temperature of 1 gram of a given substance

  by 1 oC or 1 K.
• Molar Heat Capacity (cmol)

  ● the amount of energy needed to raise

  the temperature of 1 mole of a given

  substance by 1 oC or 1 K.
• Exothermic Reactions

  ● a chemical process that releases energy to the surroundings in the form of heat
• Exothermic reactions are reactions

  that release energy, usually in the

  form of heat or light.