Karnataka SSLC Science (KSEAB) cheat sheet

Combination: A + B → AB (e.g., CaO + H2O → Ca(OH)2, highly exothermic). Decomposition: AB → A + B, driven by heat, light, or electricity.

Thermal decomposition of FeSO4 gives Fe2O3 + SO2 + SO3; electrolysis of water gives H2 (cathode, double volume) and O2 (anode).

Displacement: more reactive metal displaces less reactive one (Fe + CuSO4 → FeSO4 + Cu). Double displacement exchanges ions (AgNO3 + NaCl → AgCl↓ + NaNO3).

Oxidation = gain of oxygen or loss of hydrogen/electrons; reduction = loss of oxygen or gain of hydrogen/electrons. Both occur together in a redox reaction.

Rusting of iron needs both oxygen and moisture; 4Fe + 3O2 + xH2O → 2Fe2O3·xH2O. Prevent by painting, galvanising, or alloying.

Balancing uses hit-and-trial on atoms; never change subscripts. State symbols (s), (l), (g), (aq) and conditions are written above the arrow.

Exothermic reactions release heat (respiration, burning); endothermic absorb heat (photosynthesis, decomposition of CaCO3).

Fe + H2O(steam) → Fe3O4 + H2; metals above hydrogen in reactivity series displace H2 from dilute acids, but Cu, Ag, Au do not.

Acid: produces H3O+ in water (Arrhenius) or donates a proton (Brønsted). Base: accepts proton or gives OH−. Acid + base → salt + water (neutralisation).

pH scale 0–14: pH < 7 acidic, pH = 7 neutral, pH > 7 basic. pH = −log10[H+]; each unit change is a tenfold change in H+ concentration.

Metal + acid → salt + H2. Metal carbonate/bicarbonate + acid → salt + H2O + CO2 (limewater turns milky). Metal oxide/hydroxide + acid → salt + water.

Acid + base → salt + water. Common salts: NaCl, Na2SO4, CuSO4, NaHCO3 (baking soda), Na2CO3·10H2O (washing soda).

Chlor-alkali process (electrolysis of brine) gives Cl2 at anode, H2 at cathode, NaOH near cathode. Used for PVC, soap, bleach.

Bleaching powder: CaOCl2 (from Ca(OH)2 + Cl2). Baking powder: NaHCO3 + tartaric acid. Plaster of Paris: CaSO4·½H2O, set by adding water.

Acid rain (pH < 5.6) due to SO2, NO2; damages buildings (marble corrosion) and aquatic life. Antacids neutralise stomach HCl; tooth enamel (Ca3(PO4)2) erodes below pH 5.5.

Strong acids (HCl, H2SO4, HNO3) ionise completely; weak acids (CH3COOH, H2CO3) partially. Strong bases: NaOH, KOH; weak base: NH4OH.

Metals: lustrous, malleable, ductile, sonorous, good conductors. Non-metals: brittle, poor conductors (except graphite). Mercury is a liquid metal; bromine a liquid non-metal.

Reactivity series (high→low): K, Na, Ca, Mg, Al, Zn, Fe, Pb, (H), Cu, Hg, Ag, Au, Pt. Metals above H displace H2 from dilute acids.

Metal + O2 → metal oxide. Reactive metals (Na, K) react with cold water; less reactive (Fe, Zn) react with steam; Cu, Ag, Au do not react with water.

Ionic bond: metal loses electrons (cation), non-metal gains (anion), e.g., NaCl. Metals conduct because of free electrons; ions conduct in molten/aqueous state.

Thermite reaction: Fe2O3 + 2Al → 2Fe + Al2O3 (used to weld railway tracks). Al is used for extraction of Cr, Mn from their oxides.

Metallurgy: concentration (froth flotation, magnetic separation) → roasting (sulphide) or calcination (carbonate) → reduction (C, CO, or electrolysis for K, Na, Ca, Al) → refining (electrolysis).

Alloys: steel (Fe + C), brass (Cu + Zn), bronze (Cu + Sn), solder (Pb + Sn), amalgam (metal + Hg). Alloying improves strength and corrosion resistance.

Corrosion: rusting of iron (Fe2O3·xH2O) and tarnishing of Ag (Ag2S). Galvanising (Zn coating) and electroplating protect metals.

Carbon is tetravalent (4 valence electrons), forms strong covalent bonds with itself (catenation) and other elements (tetravalency), giving millions of compounds.

Homologous series: same functional group, differ by CH2 (14 u). Alkanes CnH2n+2, alkenes CnH2n, alkynes CnH2n−2; C1–C4 are gases, C5–C17 liquids, C18+ solids.

Functional groups: −OH (alcohol), −CHO (aldehyde), −COOH (carboxylic acid), −CO− (ketone), −X (halide). Isomers have same formula, different structure (e.g., C4H10, C5H12).

Saturated hydrocarbons burn with a clean blue flame; unsaturated give a sooty flame. C + O2 → CO2 (complete); 2C + O2 → 2CO (incomplete, toxic).

Ethanol: C2H5OH, bp 78 °C, miscible with water; used in alcoholic drinks, as fuel, solvent. Fermentation: C6H12O6 → 2C2H5OH + 2CO2 (zymase).

Ethanoic acid (CH3COOH): weak acid, reacts with NaHCO3 giving CO2, with ethanol forms ethyl ethanoate (esterification, H2SO4 catalyst).

Soaps are salts of long-chain fatty acids (RCOONa); form micelles in water. Detergents (sulphonates) work even in hard water because their Ca/Mg salts are soluble.

Hard water forms scum with soap. Soap is made by saponification: fat + NaOH → soap + glycerol.

Nutrition: autotrophic (photosynthesis) vs heterotrophic (holozoic, saprophytic, parasitic). Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2 (chlorophyll, sunlight).

Human digestive tract: mouth (salivary amylase) → stomach (HCl, pepsin) → small intestine (bile, pancreatic juice, lipase, trypsin) → large intestine. Absorption via villi.

Respiration: glycolysis in cytoplasm; aerobic respiration in mitochondria gives 38 ATP; anaerobic in muscle gives lactic acid (cramp); in yeast gives ethanol + CO2.

Human respiratory system: nostrils → trachea → bronchi → bronchioles → alveoli (site of gas exchange). Diaphragm and ribs drive breathing; alveoli have thin walls and rich capillaries.

Human heart: 4 chambers; right side pumps deoxygenated blood to lungs, left side pumps oxygenated to body. Double circulation; valves prevent backflow. Heartbeat ~72/min.

Blood: plasma, RBC (haemoglobin, O2 transport), WBC (immunity), platelets (clotting). Blood vessels: arteries (thick, high pressure), veins (valves), capillaries (exchange).

Excretion: kidneys filter blood; nephron is the functional unit. Urine formation: filtration → reabsorption → secretion. Dialysis replaces kidney function.

Plants: xylem transports water/minerals upward (transpiration pull), phloem transports food (translocation). Stomata control gas exchange and water loss.

Neuron: dendrite (receives) → cell body → axon → axon terminal. Sensory neuron carries impulse to CNS; motor neuron carries impulse to effector; interneuron connects them.

Reflex action: rapid, involuntary response via reflex arc (receptor → sensory neuron → spinal cord → motor neuron → effector). Protects body from harm.

Synapse: junction between neurons; impulse crosses via neurotransmitter (chemical). Myelin sheath speeds conduction.

Human brain: cerebrum (thinking, memory), cerebellum (balance, posture), medulla (respiration, heartbeat, blood pressure), hypothalamus (temperature, hunger, hormones).

Endocrine glands: pituitary (master), thyroid (thyroxine, needs iodine), pancreas (insulin, glucagon), adrenal (adrenaline), gonads (sex hormones).

Hormones are chemical messengers secreted into blood, act on target organs. Feedback control maintains hormone levels (e.g., insulin lowers blood glucose).

Plant hormones: auxin (growth, phototropism), gibberellin (stem elongation), cytokinin (cell division), abscisic acid (dormancy, stress).

Tropisms: phototropism (light), geotropism (gravity), hydrotropism (water), thigmotropism (touch). Nastic movements (e.g., touch-me-not) are non-directional.

Asexual modes: binary fission (Amoeba, Paramecium), budding (yeast, Hydra), fragmentation (Spirogyra), regeneration (Planaria), spore formation (Rhizopus), vegetative propagation (potato, sugarcane).

Sexual reproduction involves gametes and meiosis, producing genetic variation. Fertilisation may be external (fish, frog) or internal (humans, reptiles, birds).

Flower parts: sepals, petals, stamens (anther + filament), carpel (stigma, style, ovary). Pollination (self or cross) → fertilisation → seed and fruit.

Human male: testes produce sperm and testosterone; sperm duct, seminal vesicle, prostate, urethra. Human female: ovaries produce ova and oestrogen/progesterone; fallopian tube is site of fertilisation.

Menstrual cycle ~28 days; ovulation around day 14; menstruation if no fertilisation. Placenta exchanges nutrients, gases, wastes between mother and embryo.

Contraception: barrier (condom), hormonal (pills), intrauterine device, surgical (vasectomy, tubectomy). Prevents STDs as well as pregnancy.

STDs: gonorrhoea, syphilis (bacterial), HIV/AIDS, warts (viral). Spread by sexual contact; prevention by safe practices.

Variation arises from DNA copying errors and sexual reproduction; helps species survive environmental change.

Mendel's laws: dominance (F1 shows dominant trait), segregation (alleles separate in gametes), independent assortment (traits inherited independently).

Monohybrid cross ratio: 3:1 phenotypic, 1:2:1 genotypic. Dihybrid cross ratio: 9:3:3:1. Genotype vs phenotype.

Terms: allele, dominant, recessive, homozygous, heterozygous, hybrid. Punnett square predicts offspring probabilities.

Sex determination in humans: XX female, XY male; father's sperm determines sex. Traits: dominant (free ear lobes, tongue rolling), recessive (attached lobes).

Evolution: gradual change in inherited traits over generations. Evidence: fossils, homologous organs (same origin, different function), analogous organs (different origin, same function).

Darwin's natural selection: variation, competition, survival of the fittest, reproduction. Acquired traits are not inherited (Weismann).

Speciation: geographic isolation, reproductive isolation, genetic drift, natural selection. Evolution is not 'progress' toward a goal.

Human evolution: Homo sapiens arose in Africa; evolutionary relationships studied by DNA sequence homology.

Laws of reflection: angle of incidence = angle of reflection; incident ray, reflected ray, normal lie in one plane. Plane mirror: virtual, erect, same size, laterally inverted.

Spherical mirrors: concave (converging, real or virtual image), convex (diverging, always virtual, erect, diminished). Mirror formula 1/v + 1/u = 1/f; magnification m = −v/u.

Sign convention: object distance u negative, focal length f negative for concave, positive for convex; real image v negative.

Refraction: bending of light due to change in speed. Snell's law: n1 sin i = n2 sin r. Refractive index n = c/v = sin i / sin r.

Refraction through glass slab: emergent ray parallel to incident ray; lateral displacement. Light bends toward normal when entering denser medium.

Lens formula 1/v − 1/u = 1/f; magnification m = v/u. Convex lens: converging, real or virtual; concave: diverging, always virtual, diminished.

Power of lens P = 1/f (metres), unit dioptre (D). Power of combination: P = P1 + P2 + ...

Total internal reflection occurs when light travels from denser to rarer medium and i > critical angle; used in optical fibres, diamonds.

Eye parts: cornea (refracts light), iris (controls pupil size), lens (fine focus), retina (rods and cones), optic nerve. Rods detect dim light; cones detect colour.

Accommodation: ciliary muscles change lens shape to focus near/far objects. Near point ~25 cm; far point infinity.

Myopia (short sight): image before retina; corrected by concave lens. Hypermetropia (long sight): image behind retina; corrected by convex lens. Presbyopia: loss of accommodation with age; bifocal lens.

Dispersion: white light splits into seven colours (VIBGYOR) through a prism because each colour has a different refractive index; red bends least, violet most.

Rainbow: dispersion + refraction + total internal reflection in water droplets; primary rainbow has red outside, violet inside.

Scattering: blue sky because shorter wavelengths scatter more (Rayleigh); red at sunset because blue is scattered away over long path.

Tyndall effect: scattering of light by colloidal particles (visible beam in dusty room, fog, smoke).

Atmospheric refraction causes twinkling of stars and advanced sunrise/delayed sunset; planets do not twinkle because they are extended sources.

Current I = Q/t (ampere). Conventional current flows from + to − terminal. Potential difference V = W/Q (volt). 1 V = 1 J/C.

Ohm's law: V = IR at constant temperature. Resistance R = ρL/A; ρ is resistivity (Ω·m), depends on material and temperature, not on shape.

Series: R = R1 + R2 + ...; same current through all. Parallel: 1/R = 1/R1 + 1/R2 + ...; same voltage across all.

Electric power P = VI = I²R = V²/R (watt). Energy = P × t; commercial unit kWh = 1 unit = 3.6 × 10⁶ J.

Heating effect: H = I²Rt (Joule's law). Used in electric iron, heater, fuse; fuse wire has low melting point and high resistance.

Electric current produces magnetic field; a compass deflects near a wire. Voltmeter connected in parallel, ammeter in series (low resistance).

Resistivity of conductors increases with temperature; semiconductors decrease. Alloys used in heating elements because of high resistivity and high melting point.

1 kWh = 1000 W × 3600 s = 3.6 × 10⁶ J. 1 A = 1 C/s. 1 Ω = 1 V/A.

Magnetic field lines run from N to S outside a magnet; they never intersect. Field is stronger where lines are closer (poles).

Right-hand thumb rule: thumb = current direction, curled fingers = magnetic field direction for a straight conductor.

Fleming's left-hand rule: forefinger = field, middle = current, thumb = force on conductor. Used for electric motor.

Fleming's right-hand rule: forefinger = field, thumb = motion, middle = induced current. Used for generator.

Electromagnetic induction (Faraday): changing magnetic field induces EMF; induced current direction opposes the change (Lenz's law).

Solenoid with current acts as a bar magnet; field inside is uniform. Electromagnet: soft iron core with coil; strength depends on current, turns, core.

Electric motor converts electrical to mechanical energy; generator converts mechanical to electrical energy (AC from coil rotating in field).

Domestic circuits: live (red/brown), neutral (black/blue), earth (green). Fuse and earth wire protect against overload and leakage; AC in India is 220 V, 50 Hz.