CHEMISTRY

• SPONTANEOUS PROCESS occur so as to decrease the energy of the system. This explains why a ball rolls down a hill and also explains why a large number of exothermic reactions are spontaneous.
• Melting of ice is SPONTANEOUS.
• Dissolution of ammonium nitrate in water is also spontaneous and endothermic.
• Decomposition of Mercury III aside is an endothermic reaction

  that is nonspontaneous at room temperature and Spontaneous when temperature increases.
• EXOTHERMICITY focus the spontaneity of a chemical reaction cannot be based solely on the basis of the energy changes in the system.
• ENTROPY, measure of the randomness or disorder of a system.
• The great the disorder of the system, the stronger the entropy
• The more ordered the entropy, the lesser the entropy.
• ENTROPY is the processes that lead to an increased in entropy of the system; MELTING, VAPORIZATION, DISSOLVING, HEALING.
• A positive value of ΔS indicates that the process leads to an increase in entropy of the universe.
• Entropy change (ΔS) = Entropy of products - Entropy of reactants
• Entropy change of the surroundings (ΔSsurr) = -ΔH/T
• HYDRATION is the process that leads to a decreased of entropy.
• UNIT OF ENTROPY; in an isothermal process, the change in entropy is the change in heat divided by the absolute temptemperature.
• Standard entropy values have been measured in J/k • mole
• EXOTHERMIC, movement of the heat from the system to the surroundings.
• ENDOTHERMIC, the system absorbs energy from the surroundings
• The most stable Carbon is GRAPHITE
• 1 atm = 760 mmHg and at 25° C
• DEVICES USED FOR MEASURING PRESSURE: Water Barometer, Mercury Barometer, Aneroid Barometer.
• Aneroid barometer does not use any liquid or gas as its measuring medium.
• COMBUSTION PROCESS:

  $CH₄(g) +$$2O₂(g) -> CO₂(g) +$$2H₂O(/) ∆H° =$$-840 kJ$
• ACID BASE REACTION:

  H^+ (aq) + OH^-(g) -> H₂O(\) ∆H° = -56.2 kJ
• ∆H° subscript of F Graphite= 0
• • In state changes, entropy change is given by; ∆S =  S (subscript of f) - S (subscript of i)
• THE SECOND LAW OF THERMODYNAMICS:

  The entropy of the universe increases in a spontaneous process and remains unchanged in a equilibrium process.
• FOR A SPONTANEOUS PROCESS:

  $∆Sᵤₙᵢᵥ =$$∆Sₛᵧₛ +$$∆Sₛᵣᵣ > 0$
• FOR A EQUILIBRIUM PROCESS:

  $∆Sᵤₙᵢᵥ =$$∆Sₛᵧₛ +$$∆Sₛᵣᵣ=$$0$
• ENTHALPY; overall energy of the system
• ENTHALPY is the sum of internal energy and the product of pressure and volume.
• MATTER: occupies space and has mass
• You cannot determine the internal energy of a substance.
• Can't determine the Value of U (Internal energy)
• EQUATION OF ENTHALPY:

  $H=$$U +$$PV$ 
• Enthalpy


  Sum of internal energy and the product of pressure and volume
• Mole


  Grams to weight or the numerically equal of the atomic
• Exothermic


  Movement of the heat from the system to the surroundings
• Open System


  The system wherein actually a free or exchange interaction of mass and energy
• Closed system


  Free exchange between system and the surroundings but there's no exchange of "mass" only energy
• Equilibrium process

  The balance of all things