UPMSP High School Science cheat sheet

Combination reaction: two or more reactants form a single product, e.g. CaO + H2O → Ca(OH)2 with heat released.

Decomposition reaction: one reactant breaks into two or more products; thermal decomposition of CaCO3 gives CaO + CO2 on heating.

Displacement reaction: a more reactive element replaces a less reactive one in a compound, e.g. Fe + CuSO4 → FeSO4 + Cu.

Double displacement reaction: ions exchange partners, e.g. Na2SO4 + BaCl2 → BaSO4 (white precipitate) + 2NaCl.

Oxidation is loss of electrons or gain of oxygen; reduction is gain of electrons or loss of hydrogen; both occur together in redox reactions.

Balancing equations conserves mass: atom counts of each element must be equal on both sides; never change subscripts, only coefficients.

Exothermic reactions release heat (respiration, combustion); endothermic reactions absorb heat (decomposition of calcium carbonate).

Corrosion (rusting of iron needs both oxygen and moisture) and rancidity (oxidation of fats/oils) are slow oxidation processes; antioxidants and nitrogen flushing slow rancidity.

Acids release H+ (H3O+) in water, turn blue litmus red, and have pH below 7; bases release OH-, turn red litmus blue, and have pH above 7.

pH scale runs 0-14; pH 7 is neutral. Lower pH means higher H+ concentration; each unit change is a tenfold change in H+ concentration.

Strong acids (HCl, H2SO4, HNO3) ionise completely; weak acids (acetic acid, carbonic acid) ionise partially.

Neutralisation: acid + base → salt + water, e.g. HCl + NaOH → NaCl + H2O; the reaction is exothermic.

Metal carbonate/bicarbonate + acid gives salt + water + CO2, e.g. NaHCO3 + HCl → NaCl + H2O + CO2; the gas turns limewater milky.

Metal + acid gives salt + hydrogen gas, e.g. Zn + dilute H2SO4 → ZnSO4 + H2; burning splint gives a pop sound.

Common salt (NaCl) is raw material for NaOH (chlor-alkali process), chlorine, HCl, and washing soda; NaOH with CO2 gives Na2CO3·10H2O.

Bleaching powder is CaOCl2 from Cl2 + dry slaked lime; baking powder is NaHCO3 plus a mild edible acid; plaster of Paris is CaSO4·½H2O.

Metals are malleable, ductile, sonorous, and good conductors; non-metals are brittle, poor conductors (except graphite), and mostly gases or soft solids.

Reactivity series (decreasing): K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au; a metal displaces any metal below it from its salt solution.

Metals above hydrogen in the series react with dilute acids to give hydrogen; copper, silver, and gold do not.

Metal oxides are generally basic (Na2O, MgO); non-metal oxides are generally acidic (CO2, SO2); amphoteric oxides like Al2O3 and ZnO react with both acids and bases.

Ionic bonding: metal atoms lose electrons to form cations, non-metal atoms gain electrons to form anions; the lattice gives high melting points.

Extraction: highly reactive metals by electrolysis, moderately reactive by reduction with carbon, less reactive metals found native or extracted by displacement.

Roasting heats a sulphide ore in air (ZnS → ZnO); calcination heats a carbonate ore in limited air (CaCO3 → CaO).

Alloys are homogeneous mixtures that modify properties: brass is Cu + Zn, bronze is Cu + Sn, solder is Pb + Sn, and steel is Fe + C.

Carbon forms four covalent bonds, giving catenation (chains/rings) and tetravalency, the basis of the huge number of organic compounds.

Saturated hydrocarbons (alkanes, CnH2n+2) give substitution reactions with halogens in sunlight; unsaturated ones (alkenes, alkynes) give addition reactions.

General formulas: alkane CnH2n+2, alkene CnH2n, alkyne CnH2n-2; the first members are methane, ethene, and ethyne.

Functional groups: alcohol -OH, aldehyde -CHO, ketone -CO-, carboxylic acid -COOH, and halo- substituents; the suffix of the name reflects the group.

Ethanol is produced by fermentation of sugar with yeast; it reacts with sodium to give hydrogen and is oxidised by alkaline KMnO4 to ethanoic acid.

Ethanoic acid (acetic acid) is a weak acid; it reacts with NaHCO3 to give CO2 and with ethanol in the presence of acid to form an ester (sweet smell).

Soaps are sodium/potassium salts of long-chain fatty acids; their hydrocarbon tail dissolves grease while the ionic head dissolves in water, forming micelles.

Hard water forms scum with soap; detergents work in hard water because their calcium salts stay soluble.

Autotrophic nutrition: photosynthesis uses CO2 + H2O with chlorophyll and sunlight to give glucose + O2; it occurs in chloroplasts.

Stomata allow gas exchange; guard cells swell to open them in light and lose water to close them.

Human digestion: amylase in saliva digests starch; pepsin in the stomach digests protein in acid; bile emulsifies fats; lipase and trypsin act in the small intestine.

Human respiration: aerobic breakdown of glucose gives CO2 + H2O + much energy; anaerobic in muscles gives lactic acid and cramps; in yeast it gives ethanol + CO2.

Human transport: the heart has four chambers; arteries carry blood away from the heart, veins toward it, and capillaries allow exchange; double circulation keeps oxygenated and deoxygenated blood separate.

Xylem transports water and minerals upward; phloem transports food in both directions; transpiration pull drives water movement.

Nephron is the functional unit of the kidney: filtration in the glomerulus, selective reabsorption in the tubule, and urine formation.

Excretion in plants: stomata and lenticels lose gases and water; resins and gums are stored in old xylem.

Neuron parts: dendrite receives, cell body integrates, axon conducts, and the synapse transmits the impulse via neurotransmitters.

Reflex action is a rapid involuntary response through a reflex arc (receptor → sensory neuron → spinal cord → motor neuron → effector), bypassing the brain.

Cerebrum controls thinking and voluntary action; cerebellum controls posture and balance; medulla oblongata controls involuntary actions such as breathing.

Endocrine glands secrete hormones into the blood: pituitary (growth hormone), thyroid (thyroxine, needs iodine), pancreas (insulin), adrenal (adrenaline), and gonads.

Insulin lowers blood glucose; its deficiency causes diabetes mellitus; thyroxine regulates carbohydrate, protein, and fat metabolism.

Adrenaline prepares the body for emergencies by raising heart rate and breathing and releasing glucose into the blood.

Plant tropisms: phototropism is a response to light, geotropism to gravity, and hydrotropism to water; auxin promotes cell elongation on the shaded side.

Nastic movements such as the touch-me-not leaf are growth-independent responses to touch; abscisic acid inhibits growth and closes stomata.

Asexual modes: binary fission (Amoeba), multiple fission (Plasmodium), budding (yeast, Hydra), fragmentation (Spirogyra), regeneration (Planaria), and spore formation (Rhizopus).

Vegetative propagation in plants uses stems, roots, or leaves; examples are potato (tuber), sugarcane (stem), and Bryophyllum (leaf buds).

Asexual reproduction produces genetically identical offspring (clones) and needs no gamete fusion.

Sexual reproduction in flowering plants: pollen lands on stigma, a pollen tube reaches the ovule, and fertilisation forms a zygote that becomes the embryo; the ovule becomes the seed and the ovary the fruit.

Human male reproductive parts: testes produce sperm and testosterone; vas deferens carries sperm; prostate and seminal vesicles add fluid.

Human female parts: ovaries release ova; the fallopian tube is the site of fertilisation; the uterus supports the embryo; the placenta provides exchange.

Menstruation occurs about every 28 days when an egg is not fertilised; the uterine lining breaks down and is shed with blood.

Contraception methods include barrier (condom), hormonal (pills), intrauterine devices, and surgical sterilisation (vasectomy, tubectomy).

Mendel's law of segregation: two alleles of a gene separate during gamete formation so each gamete gets one allele.

Monohybrid cross of TT × tt gives F1 all Tt (tall) and F2 a 3:1 phenotypic and 1:2:1 genotypic ratio.

Dihybrid cross of two heterozygous parents gives F2 a 9:3:3:1 phenotypic ratio; independent assortment explains this.

Dominant allele expresses in the heterozygous state; recessive allele expresses only when homozygous; genotype is the allele pair, phenotype is the visible trait.

Sex determination in humans is XY: the father contributes X or Y, so the father's gamete determines the child's sex.

Acquired traits (from environment or use) are not passed on; inherited traits are carried by genes on chromosomes in the gametes.

Speciation occurs when populations are reproductively isolated by geographic barriers, genetic drift, or natural selection.

Evolution evidence includes homologous organs (same origin, different function), analogous organs (different origin, same function), and fossils.

Laws of reflection: the angle of incidence equals the angle of reflection, and the incident ray, reflected ray, and normal lie in one plane.

For a spherical mirror of focal length f and object distance u and image distance v: 1/v + 1/u = 1/f, with sign convention distances measured from the pole.

Magnification m = h'/h = -v/u for mirrors; positive m means a virtual, erect image.

Concave mirrors form real inverted images beyond the focus and virtual erect images for objects within the focus; convex mirrors always form virtual, erect, diminished images.

Refraction: light bends toward the normal when entering a denser medium, and away when entering a rarer medium.

Snell's law: n1 sin i = n2 sin r; refractive index n = c/v = sin i / sin r for the pair of media.

Lens formula: 1/v - 1/u = 1/f; power P = 1/f (in metres), measured in dioptres (D); converging lens power is positive.

Lens magnification m = v/u; a convex lens forms a real inverted image when the object is beyond f, and a virtual magnified image when the object is within f.

Eye parts: cornea refracts most light, iris controls pupil size, lens fine-focuses, and the retina holds rods (dim light) and cones (colour).

The near point is about 25 cm and the far point infinity for a normal eye; the ciliary muscles change lens focal length (accommodation).

Myopia (short-sightedness) is corrected by a concave lens; hypermetropia (long-sightedness) is corrected by a convex lens; presbyopia is age-related loss of accommodation.

Dispersion splits white light into seven colours (VIBGYOR) because each colour has a different refractive index in glass.

A rainbow forms by dispersion, internal reflection, and refraction of sunlight in raindrops, with the sun behind the observer.

Atmospheric refraction causes the apparent flattening of the sun at sunrise and sunset and twinkling of stars.

Scattering of light makes the sky blue (shorter wavelengths scatter more) and the setting sun red (longer wavelengths travel farther).

The Tyndall effect is scattering of light by colloidal particles, visible as a beam passing through a dusty room.

Ohm's law: V = IR at constant temperature; resistance R in ohms, with V in volts and I in amperes.

Resistance R = ρL/A: it increases with length, decreases with cross-sectional area, and depends on the material's resistivity ρ.

Series circuit: R = R1 + R2 + ...; current is the same everywhere and voltage divides.

Parallel circuit: 1/R = 1/R1 + 1/R2 + ...; voltage is the same across branches and current divides.

Electric power P = VI = I²R = V²/R, measured in watts; electrical energy is P × t, and 1 kWh = 3.6 × 10⁶ J.

Joule's law of heating: heat H = I²Rt, the basis of electric heaters, irons, and fuses.

Current I = Q/t; one ampere is one coulomb per second; conventional current flows opposite to electron flow.

A fuse or circuit breaker protects circuits by melting or tripping when current exceeds a safe value; household wiring is parallel.

A current-carrying conductor produces a magnetic field; field lines around a straight wire form concentric circles and the field strength falls with distance.

Right-hand thumb rule: point the thumb along the current and the curled fingers give the direction of the magnetic field.

Solenoid: a current-carrying coil behaves like a bar magnet; inserting a soft iron core makes an electromagnet.

Fleming's left-hand rule gives the force on a current-carrying conductor in a magnetic field (forefinger field, middle finger current, thumb force).

Fleming's right-hand rule gives the direction of induced current; electromagnetic induction requires relative motion between conductor and magnet.

An electric motor converts electrical energy to mechanical energy; a generator converts mechanical energy to electrical energy using induction.

Domestic AC in India is about 220 V at 50 Hz; the direction of current reverses every half cycle.

Renewable sources: solar (photovoltaic cells), wind, hydro, biomass, and geothermal; fossil fuels (coal, petroleum) are non-renewable and release CO2 and pollutants.