Class 12 Chemistry

Solid State Class 12 Chemistry

Solid State (ठोस अवस्था) – Important Formulas

1. Density (d) = ZM / a³N_A
2. Packing Efficiency = (Volume of atoms / Volume of unit cell) ×100
3. Edge length (Simple Cubic) a = 2r
4. Edge length (BCC) a = 4r/√3
5. Edge length (FCC) a = 2√2 r
6. Atoms in SC = 1
7. Atoms in BCC = 2
8. Atoms in FCC = 4
9. Coordination number (SC) = 6
10. Coordination number (BCC) = 8
11. Coordination number (FCC) = 12
12. Packing efficiency (SC) = 52.4%
13. Packing efficiency (BCC) = 68%
14. Packing efficiency (FCC) = 74%
15. No. of Tetrahedral voids = 2N
16. No. of Octahedral voids = N
17. Radius ratio (Octahedral) = 0.414
18. Radius ratio (Tetrahedral) = 0.225
19. Radius ratio (Cubic) = 0.732
20. Bragg’s equation: nλ = 2d sinθ
21. Interplanar distance: d = a/√(h²+k²+l²)
22. Volume of unit cell = a³
23. Mass of unit cell = ZM/N_A
24. Density = mass/volume
25. Z = number of atoms per unit cell
26. M = molar mass
27. N_A = 6.022 ×10²³
28. Fraction of corner atoms = 1/8
29. Fraction of face centred atoms = 1/2
30. Fraction of body centred atom = 1

Solutions Class 12 Chemistry

Solutions (विलयन) – Important Formulas

1. Molarity (M) = moles of solute / volume of solution (L)
2. Molality (m) = moles of solute / mass of solvent (kg)
3. Mole fraction (X_A) = moles of A / total moles
4. X_A + X_B = 1
5. % by mass = (mass of solute / mass of solution) ×100
6. % by volume = (volume of solute / volume of solution) ×100
7. ppm = parts of solute / 10⁶ parts of solution
8. ppb = parts of solute / 10⁹ parts of solution
9. Raoult’s Law: P_A = P°_AX_A
10. Relative lowering of vapour pressure = (P°-P)/P°
11. (P°-P)/P° = X_B
12. Elevation in boiling point: ΔT_b = K_bm
13. Depression in freezing point: ΔT_f = K_fm
14. Osmotic pressure: π = CRT
15. π = (n/V)RT
16. van’t Hoff factor: i = observed / calculated
17. Molar mass = wRT / πV
18. Henry’s Law: P = K_HX
19. ΔT_b = iK_bm
20. ΔT_f = iK_fm
21. Normality (N) = equivalents / volume
22. M = n/V
23. m = w/M × 1000/W
24. X_A = n_A/(n_A+n_B)
25. P = X_AP°_A
26. Total Pressure = P_A+P_B
27. Osmotic pressure ∝ concentration
28. R = 0.0821 L atm mol⁻¹ K⁻¹
29. K = 273 + t°C
30. Colligative properties depend on number of particles

Electrochemistry Class 12

Electrochemistry (वैद्युत रसायन) – Important Formulas

1. E_cell = E°_cathode − E°_anode
2. ΔG = −nFE_cell
3. ΔG° = −nFE°_cell
4. E°_cell = (0.0591/n) logK
5. Nernst Equation: E = E° − (0.0591/n) logQ
6. Conductance (G) = 1/R
7. Specific conductance (κ) = G × (l/A)
8. Molar conductivity (Λ_m) = κ × 1000/M
9. Equivalent conductivity = κ × 1000/N
10. Resistivity (ρ) = 1/κ
11. R = ρl/A
12. Cell constant = l/A
13. Λ_m = Λ°_m − K√c
14. Faraday constant (F) = 96500 C
15. m = ZIt
16. Z = E/F
17. Q = It
18. E = w/n
19. Λ_m = λ⁺ + λ⁻
20. Degree of dissociation α = Λ_m/Λ°_m
21. Kohlrausch Law
22. EMF = Potential difference
23. E = IR
24. ΔG° = −RT lnK
25. K = antilog(nE°/0.0591)
26. I = Q/t
27. Oxidation at anode
28. Reduction at cathode
29. Galvanic cell E° > 0
30. Electrolytic cell needs energy

Chemical Kinetics Class 12

Chemical Kinetics (रासायनिक गतिकी) – Important Formulas

1. Rate = −d[A]/dt
2. Rate = d[P]/dt
3. Rate law: Rate = k[A]^m[B]ⁿ
4. Order = m + n
5. Molecularity
6. First order: k = 2.303/t log(a/a−x)
7. Half life (1st order): t½ = 0.693/k
8. Zero order: k = x/t
9. Half life (0 order): t½ = a/2k
10. Second order: k = 1/t [(1/a−x) − (1/a)]
11. Half life (2nd order): t½ = 1/ka
12. Arrhenius eqn: k = Ae^−Ea/RT
13. logk = logA − Ea/2.303RT
14. Ea = 2.303R (logk₂ − logk₁)/(1/T₁ − 1/T₂)
15. k ∝ e^−Ea/RT
16. R = 8.314 J/mol K
17. Rate constant unit depends on order
18. Temperature ↑ → rate ↑
19. Catalyst lowers Ea
20. Integrated rate eqn
21. Rate ∝ concentration
22. Pseudo first order reaction
23. t½ independent of concentration (1st)
24. t½ ∝ concentration (0 order)
25. t½ ∝ 1/concentration (2nd)
26. Reaction mechanism
27. Activation energy (Ea)
28. Collision theory
29. Frequency factor (A)
30. Effective collision