1. PREPARED BY: NOR SYAFINAZ BINTI ABDUL GHANI MIC2A2 2010466248

2. THERMOCHEMISTRY

3.  Thermal energy is the energy associated with the random motion of atoms and molecules.  Heat is the transfer of thermal energy between two bodies that are different temperature.  Temperature is a measure of thermal energy.

4. Enthalpy of a system is the heat content of the system or the sum of the internal energy and the product of its pressure & volume. Also known as heat content. Enthalpy (H) is used to quantify the heat flow into and out of a system in a process that occurs at constant pressure ∆H˚=∑ H˚(products)-∑H˚(reactants) ∆H : heat given off or absorbed during a reaction at constant pressure.

5. Internal energy of reactant is greater than the product Heat released to the surrounding ∆H is negative exothermi c Internal energy of product is greater than the reactant Heat is absorbed from the surrounding ∆H is positive endothermic

6. ∆H<0 2H 2 (g) + O 2 (g) energy heat 2H 2 O(l) ∆H>0 2Hg (l) + O 2 (g) Energy heat 2HgO(s)

7. Energy released as heat when a compound undergoes complete combustion with oxygen under stated condition of temperature & pressure. The enthalpy of combustion Heat released when one mole water is formed when an acid reacts with a base under stated condition or during the neutralisation of strong acid by an alkali. The value is always negative The enthalpy of neutralisation The heat change when one mole of substance or a certain amount of solute dissolve in a certain amount of solvent. The enthalpy of solution The heat change when one mole of a compound is formed from its element s at stated temperature and pressure. The enthalpy of formation The enthalpy change in reaction when both reactantas and products are at their standard states at 298 K. The enthalpy of reaction

8. Calorimetry Measurement of heat flow. Calorimeter Apparatus that measures heat flow. Heat capacity The amount of energy required to raise the temperature of an object. Molar heat capacity Heat capacity of 1 mol of a substance. Specific heat capacity Heat capacity of 1g of a substance.

10. For any chemical change made in several steps, the net ∆H is equal to the sum of the ∆H values of the separate steps

11. Balance the equation(s). Sketch a rough draft based on ∆H values. Draw the overall chemical reaction as an enthalpy diagram. Draw a reaction representing the intermediate step. Check arrows. complete balancing – all levels must have same atoms Add axes and ∆H values.

12.  Enthalpy cycle used to calculate lattice enthalpy of an ionic compound  Two different routes to form an ionic compound.

13.  The enthalpy change when one mole of an ionic solid is formed from its gaseous ions.  The values are always negative because of formation of ionic bond.

14. CHEMICAL KINETICS

15.  The change in the concentration of a reactant or a product with time (M/s) A B reactant(-) product(+) rate of appearance = positive rate of dissapearance = negative

16.  Expresses the relationship of the rate of reaction to the rate constant and the concentrations of reactants raised to some powers. aA+bB→ cC+dD Rate = k [A] x [B] y  Order of reaction xth order in A yth order in B (x+y)th is the overall order

18.  Concentration of reactants – concentration of reactants increase, so does the likehood that reactant molecules will collide.  Temperature – at high temperature,reactants molecules have more kinetic energy,move faster and collide more often.  Catalyst – speed rxn by changing mechanism.  Activation energy – minimum amount of energy required for reaction.

19. k = A.e (-Ea/RT) E a = activation energy (J/mol) R = gas constant (8.314 J/K.mol) T = absolute temperature A = frequency factor

20.  At two temperature, T 1 and T 2 Ln k1/k2=Ea/R(1/T2-1/T1 )

21.  The overall progress of a chemical reaction represented by a series of elementary steps.  The sequence of elementary steps lead to product formation is the reaction mechanism.

22. MolecularityElementary reactionRate law UnimolecularA productRate = k[A] BimolecularA + A productRate = k[A] 2 Bimolecular A + B productRate = k[A][B] TermolecularA + A +A productRate = k[A] 3 TermolecularA + A + B productRate = k[A] 2 [B] TermolecularA + B + C product Rate = k[A][B][C]

23. CHEMICAL EQUILIBRIUM

24. Reacting species are the same phase i.e: N 2 O 2 (g) 2NO 2 (g) K’c = [ NO 2 ] 2 / [ N 2 O 2 ] Homogenous equilibrium Reactants and product are in different phases i.e: CaCo 3 (s) CaO (s) + CO 2 (g) K’c = [CaO] /[CaCo 3 ] The concentration of solid and pure liquid are not included in the expression for the equilibrium contant. Heterogenous equilibrium

25. K p = K c (RT) ∆n R = room pressure = 0.0821 ∆n = moles of gaseous products- moles og gaseous reactant

26.  If an external stress is applied to a system at equilibrium,the system adjusts in such a way that the stress is partially offset as the system reaches a new equilibrium position

27. changeShift equilibriumChange equilibrium constant Concentrationyesno PressureYesno VolumeYesno TemperatureYesyes catalystNono

28. IONIC EQUILIBRIUM

30. ᾱ = [H 3 O] / [acid] ᾱ = [H 3 O] / [acid] x 100

31. 1.For strong acid pH=-log [H] 2.For weak acid [H]=√KaC [OH]=√KbC 3.pH of Buffer pH= pKa-log[acid/salt] pOH=pKa-log[base/salt] pKa= -logKa 4. Kw = [H][OH] = Ka x Kb = 1 x 10 -4

32. PHASE EQUILIBRIUM

33.  A homogeneous system  Separated from other parts of system by a dinstinct boundary  3 phase of state solid liquid gaseous

34.  No boundary between subtances – hemogenous  i.e: g-g system : oxygen and nitrogen l-l system : water and ethanols-s system : gemstone

35.  Two substance with a boundary separating them  i.e: l-l : water and oil l-g : water and water vapour s-g : ice and water vapour s-l : ice and water

36.  3 substance with boundaries separating each other  i.e: s-l-g : ice, water and water vapour system

37.  The least number of independently variable constituents which must be specified so that composition of each and every phase is described.

38.  The smallest number of independent variables of components (temperature, pressure, concentration) which must be specified to define completely the remaining variables of the system

39. F = C – P + 2 More components, more degree of freedom More phases involved, less degree of freedom

40. Water and carbon dioxide

41. pressure, atm solid liquid 0.006 gas 0.01 temperature,( 0 c)

42. pressure, atm temperature, ( 0 c) solid liquid gas 5.1 -57

43. Two completely immisible solids (l-s)

44.  Eutectic mixture – a mixture of 2 or more subtance with melting point lower than any other mixture of the same subtance  Eutectic system – a mixture of chemical compounds or elements that has a single chemical composition that solidifies at a lower temperature than any other temperature

46. Deviation from raoult’s law

47. Negative deviation Vapour-composition diagram of solution have minimum point Boiling-composition diagram has maximum point Positive deviation Vapour-composition diagram of solution have maximum point Boiling-composition diagram has minimum point

48.  Partition coefficient= the ratio between the concentration of the solute in the two solvents is, experimentally constant.

49. Kc= [solute in upper layer]/[solute in the lower layer] Kc= X/volume of ether mass of substance-X/volume of water