Class 10 — Science — Formulas

Combination: A + B → AB | Decomposition: AB → A + B

Displacement: A + BC → AC + B | Double displacement: AB + CD → AD + CB

Oxidation: gain of O2 / loss of H2 / loss of electrons

Reduction: loss of O2 / gain of H2 / gain of electrons

Balanced equation: equal atoms of each element on both sides

Acid + Base → Salt + Water (neutralisation)

Acid + Metal → Salt + H2 | Acid + Metal oxide → Salt + Water

Acid + Metal carbonate → Salt + Water + CO2

pH scale: 0 to 14 | pH < 7: acidic | pH = 7: neutral | pH > 7: basic

Washing soda: Na2CO3·10H2O | Baking soda: NaHCO3

Plaster of Paris: CaSO4·½H2O | Bleaching powder: CaOCl2

Reactivity series (decreasing): K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au

Displacement: more reactive metal displaces less reactive from its salt solution

Thermit reaction: Fe2O3 + 2Al → 2Fe + Al2O3 + heat

Galvanisation: coating iron with zinc

Low reactivity extraction: heating in air | High reactivity: electrolysis

Alkanes: CnH(2n+2) | Alkenes: CnH(2n) | Alkynes: CnH(2n-2)

Combustion: CnH(2n+2) + O2 → CO2 + H2O + heat

Oxidation: CH3CH2OH + [O] → CH3COOH

Esterification: CH3COOH + C2H5OH → CH3COOC2H5 + H2O (conc. H2SO4 catalyst)

Saponification: ester + NaOH → alcohol + sodium salt (soap)

Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2 (sunlight, chlorophyll)

Aerobic respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

Anaerobic (muscles): C6H12O6 → 2C3H6O3 (lactic acid) + energy

Anaerobic (yeast): C6H12O6 → 2C2H5OH + 2CO2 + energy

Chambers in human heart: 4 | Filtering unit of kidney: nephron (~1 million per kidney)

Reflex arc: receptor → sensory neuron → spinal cord → motor neuron → effector

Thyroid → thyroxine (regulates metabolism)

Pancreas → insulin (regulates blood sugar)

Gonads → testosterone (male), estrogen (female)

Plant hormones: auxin (growth) | gibberellin (elongation) | cytokinin (division) | abscisic acid (inhibition)

Chromosome number in human gamete: 23

Chromosome number in zygote: 46

Menstrual cycle: about 28 days | Gestation period: about 9 months

Pollination: transfer of pollen from anther to stigma

Fertilisation: fusion of male and female gametes

Monohybrid cross ratio: 3:1 (phenotypic) | 1:2:1 (genotypic)

Dihybrid cross ratio: 9:3:3:1 (phenotypic)

Sex chromosomes: XX (female) | XY (male)

P(male child) = 1/2 | P(female child) = 1/2

Mirror formula: 1/v + 1/u = 1/f | Magnification (mirror): m = -v/u = h'/h

Lens formula: 1/v - 1/u = 1/f | Magnification (lens): m = v/u

Refractive index: n = c / v_medium

Snell's law: n1 sin i = n2 sin r

Power of lens: P = 1/f (f in metres) | Unit: dioptre (D)

Combination of lenses: P = P1 + P2 + ...

Myopia: image in front of retina → corrected by concave lens (negative power)

Hypermetropia: image behind retina → corrected by convex lens (positive power)

Dispersion: white light splits into VIBGYOR through prism

Scattering: shorter wavelengths scatter more (blue sky, Rayleigh scattering)

Electric current: I = Q/t (A) | Potential difference: V = W/Q (V)

Ohm's law: V = I × R

Resistance: R = ρ × (L/A), where ρ = resistivity

Series: R = R1 + R2 + R3 | Parallel: 1/R = 1/R1 + 1/R2 + 1/R3

Power: P = VI = I^2R = V^2/R | Energy: E = Pt

1 kWh = 3.6 × 10^6 J | Joule's law: H = I^2Rt

Force on current-carrying conductor: F = BIL (magnitude)

Fleming's left-hand rule: F, B, I mutually perpendicular (used for motor)

Fleming's right-hand rule: used for induced current (generator)

AC frequency in India: 50 Hz | AC: direction reverses periodically | DC: unidirectional

10 percent law of energy transfer: only 10% of energy at one trophic level passes to the next

Food chain: producers → primary consumers → secondary consumers → tertiary consumers

Ozone: O3 | Ozone protects from UV radiation | CFCs cause ozone depletion