HSC Chemistry Preparation Tips Part - I

1.Solid State Classification of Solids Classification of crystalline solids Unit cells, two and three dimensional lattices and number of atoms per unit cell and Number of Atoms in the unit cell : Unit cellsccbccfcchcp Number of atoms 1243 Packing efficiency : sccbccfcchcp 52.4%68 %74%74% Relation between radius (r) of an atom and edge length (a) of cubicunit cell : sccbccfcc =ar2=3r a4=ar2 2 Packing in solids Density of unit cellDensity of the crystal : =3Az Mda N Packing in voids of ionic solids Defects in crystal structure Electrical properties Magnetic properties 2.Solutions & Colligative Properties Types of solution Concentration of solution of solids in liquids Number of moles,mol Molarity =mol dm-3 (or M)Normality =gram eq.dm -3 =WnMnVgrameq.V Solubility of gases in liquids Solid solution Colligative properties andmolecular masses Lowering of vapour pressure Molality =mol kg -1 (or m) Raoults law: Psoln = x1 P0 nWt. of solvent inkg=1 0 21 0 2P P W MP WMElevation of boiling point ATb = Kbm and ATf = kf m ATb = Kb 21 2W 1000W M Depression of freezing point ATf = Kf Osmotic pressure At constant temperature : At constant concentration : 21 2W 1000W Mt=t2 21 1CCt=t2 21 1TT vant Hoff equation : t = CRT t = WRTMVnRTVt = vant Hoff factor (i) A At= = = =A A tb(ob) f(ob)ob thth ob b(th) f(th)T TMT T M( )(o = (< th obob thth(For dissociation)M M1(M M )n 1 M (| |o =|(>\ . oh thob thob(For association)M M1(M M )n 1 Mo =i 1(For dissociation)n 1| |o = |\ .n(1 i) (For association)n 1 Abnormal molecular mass Vant Hoff factor 3.Chemical Thermodynamics & Energetics Basic concepts in thermodynamics Nature of Heat and Work Internal Energy W = - P (V2 V1) = -P A V(For expansion) W = P (V2 V1) P A V(For compression) Wmax = - 2.303 nRT log10

Wmax = - 2.303 nRT log10 21VV12PP First Law of Thermodynamics Enthalpy AU = q + W H = U + PV AH = AU + PAV AH = AU + AnRT Enthalpy of physical changes Thermo chemistry Spontaneous processes (Irreversible processes) Gibbs free energy G = H TS revq HST TA= =AG = AH - TASA G0 = - 2.303 RT log10K A G = 0, the system is at equilibrium A G < 0, the process is spontaneousA G > 0, the process is non- spontaneous. Third law of thermodynamics. 4.Electrochemistry Redox Reaction Conductance in electronic solutions Resistance (R) Electrical conductance (G)or S Resistivity = OPotential difference (V)Electric current (I)= O11R = Oa( ) R cm1 Cell constant = cm-1(or m 1) Conductivity (k) Molar conductivity (m) =(k in -1

m-1 and C in mol m-3) OR a= Cell ConstantResistancekC m

(k in -1 m-1 and C in mol m-3) Kohlarauschs law : 0 Degree of dissociation Dissociation constant (ka)

+ = + 0 0.o =.m0( )=k 1000C.=. . .2mm0 0C( ) Electrochemical cells Electrolytic cells Galvanic or voltaic cells Electrode potentials and cells potential = 0 0 0cell red redE E (cathode) E (anode)+ ++= n n0M/MnM / M 100.0592E E log [M]n= 010 cell cell0.0592 [Pr oducts]EE logn [Reactants]G = nFEcell

G0 = - RTln K For spontaneous cell reaction : Ecell > 0; G < 0 A = 0 0cellGn FE=010 cell0.0592E log Kn5. Chemical Kinetics Rate of reaction For a reaction, aA + bB cC + dD Average rate = Rate law : Rate = k [A]a [B]b

A A A A = = =A A A A1 [A] 1 [B] 1 [C] 1 [D]a t b t c t d t Dependence of rate on reactant concentration log0 (for first order reaction) t = (for first order reaction) = 2.303kt0t[A][A]0.693k k =(For zero order reaction) t =(For zero order reaction Molecularity of elementary reactions Collision theory and activation energy 0[A]2kt0[A] [A]t Temperature dependence of reaction rates (Arrhenius equation) K = Ae Ea/RT (Arrhenius equation) Log10k = log10A Log10

aE2.303RT Effect of catalyst on rates of reactions = a1 2 21 1 2k E (T T )k 2.303R T T6.General & Processes of Isolation of Elements Concentration ofan ore Oxidation reduction Refining of crude metal Extraction of Zinc Extraction of Iron Extraction of Aluminium Extraction of Copper 7. pBlock Elements Group 15 elements Group 16 elements Group 17 elements Group 18 elements Reference electrodes Common types of cells Fuel cells Electrochemical series Corrosion Thank You