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  • Energetics
    • Conservation of energy law
      • Energy cannot be created or destroyed. It can only be transformed from one form to another.
    • Enthalpy
      • Specific for heat content.
        • The symbol for energy is H.
          • The symbol for enthalpy change is ^H
            • Endothermic reactions require an energy input, this means that ^H will be positive.
            • Exothermic reactions release energy which means that ^H will be negative.
    • Standard Conditions
      • Temperature of 298K (25 degrees Celsius)
      • Pressure of 1atm
      • Solutions of conc. 1moldm-3
      • Substances in their standard/most stable states.
      • Standard conditions are used to obtain values for standard enthalpy change.
        • Standard molar enthalpy change of combustion:
          • The enthalpy change when one mole of a substance burns completely in oxygen under standard conditions.
        • Standard molar enthalpy change of formation:
          • The enthalpy change when one mole of a compound forms from its elements in their standard states understand conditions.
    • Determining enthalpy changes in aqueous solution:
      • ^H = -mc^T         n
        • Enthalpy Change (KJ or J)
        • m = total mass of the solution (g) or V for total volume of solution.
        • c  = Specific heat capacity of water = 4.18Jg-1 Degree Celsius or 4.18Jg-1K
        • ^T = Temperature change (Degree Celsius or K)
        • n = Number of moles
    • Hess's Law
      • The total energy change that occurs when a system changes from one state to another is independent of the route taken.
      • Enthalpy Cycles
        • A
          • D
            • C
          • D
            • C
    • Bomb Calorimeters
      • Accurate values of enthalpy changes of combustion can be obtained using a bomb calorimeter.
        • The apparatus is specifically designed to avoid heat losses by surrounding the 'bomb' first with water and then an insulating air jacket.
          • Heating the sample in excess oxygen at high pressure ensures that combustion goes to complete combustion.


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