Obtaining energy from fuel

• One mole contains 6.022x10^23 particles, also called Avogadro's constant
• The molar volume of gas at standard lab condition is 24.8 L per mole
• Excess limiting reactants

  • The reactant that is completely consumed is the limiting factor, while the reactant that is not completely consumed is the excess reactant
  • Use the limiting reactant to calculate the amount of product formed
• Specific heat capacity of a substance is the measure of the amount of energy needed to increase the temperature of a specific quantity of that by 1 degrees
• Bomb calorimetry is used when the products or reactants are gaseous, it involves burning a fuel in a chamber and the heat transferring to the surrounding water
• Calibration factor is the amount of energy required to change the temperature of a solution by 1 degrees

  • Energy = voltage(volts) x current(amps) x time(s)
  • CF = E /Temp Change
• Chemical calibration instead uses a chemical reaction that releases a known amount of thermal energy

  • E = n x enthalpy
• The calibration factor helps determine the amount of energy responsible for the change in temperature

  • E = CF x change in temperature
• Energy transformation is the process in which a form of energy is converted into one or many other forms
• Energy efficiency is the measure of to describe the amount of useful energy converted, as energy can be lost as other less useful forms
• Often times the energy released when the food is burned is greater then the amount that is available for the body to use, due to

  • Incomplete oxidation or absorption
  • Energy is lost as heat energy