HEAT = Measure of total energy of substance which depend on amount of substance
-flow from high temperature to low temperature object

TEMPERATURE = Measure of average kinetic energy of particle in substance

• measure in Kelvin (K)
  -Absolute temperature is directly proportional to average kinetic energy of particle

Enthalpy
-Heat content of substance
-Chemical reaction that take place at constant pressure where the heat is released or absorbed, measured with enthalpy change (ΔH)

•  q = m x c x ΔT     
  

  q=heat (J)
  m= mass (g)
  c=specific heat capacity(4.18 Jg-1 K-1)
  ΔT = change in temperature (K)

STANDARD ENTHALPY CHANGE OF FORMATION
-1 mol of substance formed from its element at 298K,1atm

• H2(g)+S(s)+2O2(g) --> H2SO4(l) ΔHf = -811 kJ mol-1

•  ΔH Fomation =  Product - Reactant
  

STANDARD ENTHALPY CHANGE OF COMBUSTION
-I mol of substance completely burn in oxygen at 298 K,1 atm

• C2H4(g) + 2O2(g) --> 2CO2(g) + 2H2O(l) ΔH = -1411 kJ

•  ΔH Combustion = Reactant - Product
  

EXOTHERMIC
-heat from system released to surrounding
-surrounding temperature increase.(ΔH = +)
-Combustion,neutralisation

• Reactant is mores stable than product

ENDOTHERMIC- Temperature from surrounding is absorbed into system
-temperature surrounding decrease. (ΔH = - )
-Photosynthesis, thermal decomposition method

• Product is more stable than reactant

STANDARD MOLAR ENTHALPY OF ATOMISATION
-1 mol of separate gaseous atom is form from the element in standard state

• Na(s) --> Na(g)

STANDARD MOLAR ENTHALPY OF NEUTRALISATION
-I mol of water is form in reaction between 1 mol dm-3 acid and 1 mol dm-3 alkali in standard state

• H+(aq) + OH-(aq) --> H2O(l)

STANDARD MOLAR ENTHALPY OF LATTICE
-1 mol of crystallline solid ionic compound turn to separate gaseous ion

• NaCl (s) --> Na+(g) + Cl- (g)

-State that enthalpy change for reaction depends only on differences between enthalpy of product and enthalpy of reactant --

• ΔH = Product - Reactant
  

• 
  
  • ΔH B = ΔH A + ΔH C

Law of conservation of energy
-Energy can be neither created nor destroyed; it can be transformed from one form of energy to another.

EFFECT ON ENERGY CHANGE
-rearrangement equation = no effect
-reversing equation= changes the sign
-mutiplication equation = energy change is mutiplied
-division equation = energy change is divided
-adding two equations= energy change added together
-subtracting two equations =the energy changes are subtracted

AVERAGE BOND ENTHALPY
-the average amount of energy needed to break a specific type of bond, measured over a wide variety of different gaseous molecules.
-Bond formation = ΔH -
-Bond breaking = ΔH +

• ΔH = Reactant - Product