Important Chemistry Concepts

Chemistry

• More stable alkenes release less energy during catalytic hydrogenation.
• Ethylene reacts with dilute alkaline KMnO4 at 273 K to create ethylene glycol.
• Atomic number 113 belongs to group 13 and period 7, placing it in the Boron family.
• A greater reduction potential signifies a weaker reducing power.
• Electron-withdrawing groups increase the acidic strength of acids.
• Half-life is inversely proportional to the rate constant.
• CaCl2 has the highest van't Hoff factor, leading to a maximum freezing point depression.
• Homoleptic complexes bind a metal to only one type of donor group, K3[Co(C2O4)3] is an example.
• Aromatic compounds exhibit position isomerism but not metamerism.
• Six large chloride ions are unable to be accommodated around Si4+ and therefore SiCl62- does not exist.
• For the same alkyl group, the boiling points of alkyl halides decrease in the order : RI > RBr > RCl > RF
• n-Hexane and n-pentane form an ideal solution.
• Complex bond angles: BeCl2 is 180°, BF3 is 120°, CH4 is 109.5°, NH3 is 107°, and H2O is 104.5°.
• N2Cl reacts with HBF4 to produce N2BF4, BF3, and N2.

Thermodynamics

• Phase transitions are isothermal, with ΔG = 0 at equilibrium, ΔSsystem > 0, and ΔStotal = 0.
• As temperature increases, the equilibrium constant for exothermic reactions decreases.

Organic Chemistry

• Carbon atoms at bridgeheads do not contain enolisable hydrogen.

Nuclear Chemistry

• O2 contains 32 nucleons

Physics

• In single-electron species, energy is proportional to Z^2/n^2.
• Solar cells operate without any bias.
• In n-type semiconductors, ne >> nh.
• The emf of a battery relates to its internal mechanisms and is non-electrostatic.
• The equivalent capacitance in a series becomes C/2, and the breakdown voltage doubles.
• The moment of inertia of a rod about a perpendicular axis at its midpoint is ML^2/12.
• A constant pressure accompanies increased temperature and volume.
• Power consumption is zero in AC circuits containing only capacitors or inductors.
• A neutral body gains a positive charge when it loses electrons, thereby slightly decreasing its weight.
• The areal velocity of a planet (dA/dt) relates to its angular momentum (L).
• The velocity of electromagnetic waves in free space is c = 1/√(μοεο).

Optics

• When an object is placed at 2f of a first lens, the image forms at 20 cm behind.

Measurement

• Least Count = 0.02 mm

Wave Optics

• Fringe width and wavelength are related by β = Dλ/d.

Electricity

• The circuit redrawn with 2 kΩ gives a current of 2 mA with a 12 V battery.

Units

• 1 Kilowatt hour = 3.6 × 10^6 J
• Critical angle C is more for yellow because it has more wavelength
• Av/v = 3 (dl/I)

Biology

• Albugo candida causes white spots on mustard leaves, while Aspergillus is a lab weed.
• Sleeping sickness is from Trypanosoma, a flagellated protozoan.
• Biological names originate from Latin regardless of origin.
• Threonine represents an essential amino acid.
• In angiosperms, the egg apparatus consists of 2 synergids and 1 egg cell.
• A population possesses birth and death rates; individuals cannot.
• Net primary productivity is biomass accessible for heterotroph consumption.
• The first irreversible reaction in glycolysis, conversion of glucose to glucose-6-phosphate, is catalyzed by hexokinase.
• Selaginella and Salvinia are pteridophytes showing precursor events to seed habits.
• Microscopic analysis mandates grinding living tissue in trichloroacetic acid.
• Collagen is abundant in the animal world, and RuBisCO in the biosphere.
• Columnar epithelium supports secretion and absorption in the stomach and intestines.
• The cerebellum, the hindbrain's largest part, maintains a convoluted surface for more neurons.
• Plant growth remains indeterminate through meristematic cells, which facilitates open growth forms.
• Haemophilia: A sex-linked recessive disorder impacting a single protein in blood clotting cascades.

Genetics

• The construction of recombinant DNA involved linking an antibiotic resistance gene with Salmonella typhimurium plasmid
• β-Thalassemia is controlled by a single gene HBB on chromosome 11
• Drosophila melanogaster reproduces rapidly in simple mediums demonstrating sexual differentiation.

Human Anatomy

• Four parathyroid glands, located on the thyroid gland's rear, release parathyroid hormone (PTH) to stimulate bone resorption.
• Monomeric antibodies feature four intrachain disulphide bonds in their light chains.
• Each breast contains 15–20 mammary lobes, joined by mammary ducts to form ampulla connected to lactiferous ducts.
• Hormonal changes drive cyclical changes within the ovary and uterus.
• Right and left bundle branches produce Purkinje fibers for ventricular musculature.
• Red muscle fibres store plenty of oxygen for ATP production facilitated by a large number of mitochondria.

Cell Biology

• The Lac-Z gene encodes β-galactosidase to produce blue-colored products.
• Chains A and B are produced separately in E. Coli, and disulphide bonds are made between them to produce insulin

Ecology

• Nile perch introduction in Lake Victoria led to cichlid fish elimination,

Botany

• Earthworms assist breakdown of organic matter and soil loosening.
• Multicarpellary, apocarpous gynoecium exists in Michelia,
• Outer layer of a pollen grain(exine) has prominent apertures called germ pores where sporopollenin is absent