RBSE SS Chemistry flashcards
RBSE SS Chemistry · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Schottky defect
- A point defect in ionic solids in which one cation and one anion are missing from their lattice sites, decreasing the density of the crystal.
- Frenkel defect
- A point defect in which an ion leaves its lattice site and occupies an interstitial position, so the crystal density remains unchanged.
- Raoult's law
- For an ideal solution, the partial vapour pressure of each volatile component equals its mole fraction multiplied by the vapour pressure of the pure component at that temperature.
- van't Hoff factor
- The ratio of the observed colligative property to the value calculated for the same molar concentration assuming no dissociation or association; i is greater than one for dissociation.
- Azeotrope
- A liquid mixture that boils at constant temperature without changing composition, because its vapour has the same composition as the liquid; ethanol-water is a minimum-boiling example.
- Nernst equation
- It relates electrode potential to standard potential and reaction quotient: E = E° minus (0.0591/n) log Q at 298 K for a reaction involving n electrons.
- Kohlrausch law
- At infinite dilution, the molar conductivity of an electrolyte equals the sum of the limiting ionic conductivities of its ions multiplied by their stoichiometric coefficients.
- Fuel cell
- An electrochemical cell that converts the chemical energy of a continuously supplied fuel, such as hydrogen, and an oxidant directly into electrical energy with high efficiency.
- Order of reaction
- The sum of the powers of the concentration terms in the experimental rate law; it may be zero, fractional or negative and is not obtained from the balanced equation.
- Half-life
- The time required for the concentration of a reactant to fall to one half of its initial value; for a first-order reaction it equals 0.693 divided by k.
- Activation energy
- The minimum extra energy that colliding reactant molecules must possess to form products; a catalyst provides an alternative pathway with a lower activation energy.
- Inert pair effect
- The tendency of heavier p-block elements to show an oxidation state two units lower than the group maximum, because the ns² pair becomes reluctant to participate in bonding.
- Allotropy
- The existence of an element in two or more different structural forms in the same physical state, such as rhombic and monoclinic sulphur or white and red phosphorus.
- Lanthanoid contraction
- The steady decrease in atomic and ionic radii from lanthanum to lutetium caused by poor shielding by the increasing 4f electrons, making later lanthanoids smaller.
- Transition element
- An element whose atom or common ion has an incomplete d subshell; this explains variable oxidation states, colour, catalysis and complex formation.
- Spin-only magnetic moment
- The magnetic moment calculated from the number of unpaired electrons n using μ = √(n(n+2)) Bohr magnetons, ignoring orbital contribution.
- Chelate effect
- The extra stability of a complex formed by a polydentate ligand compared with a similar complex of monodentate ligands, largely due to favourable entropy of chelation.
- Crystal field splitting
- The energy separation Δo between the lower t₂g and higher e_g d orbitals when ligands approach a metal ion in an octahedral complex.
- SN2 mechanism
- A one-step nucleophilic substitution in which the nucleophile attacks the carbon from the side opposite the leaving group, giving inversion of configuration.
- Sandmeyer reaction
- The reaction of a diazonium salt with copper(I) chloride or bromide in the corresponding acid to form an aryl chloride or bromide with loss of nitrogen.
- Lucas test
- A test that distinguishes alcohols by the time taken to form a cloudy layer with concentrated hydrochloric acid and zinc chloride: tertiary fastest, primary slowest.
- Williamson synthesis
- The preparation of an ether by treating a sodium alkoxide with a primary alkyl halide through an SN2 reaction; tertiary halides give elimination instead.
- Aldol condensation
- The base-catalysed reaction of two carbonyl compounds having α-hydrogens to form a β-hydroxy aldehyde or ketone, which may lose water to give an α,β-unsaturated product.
- Cannizzaro reaction
- The disproportionation of an aldehyde lacking α-hydrogens in concentrated alkali, producing equal amounts of a carboxylate salt and a primary alcohol.
- Hofmann bromamide reaction
- The treatment of an amide with bromine and sodium hydroxide to give a primary amine containing one carbon atom fewer than the original amide.
- Carbylamine test
- A test for primary amines in which heating with chloroform and alcoholic potassium hydroxide produces a foul-smelling isocyanide.
- Denaturation
- The loss of the secondary, tertiary and quaternary structure of a protein by heat or pH change, without hydrolysis of its peptide bonds.
- Reducing sugar
- A carbohydrate that has a free aldehyde or ketone group and therefore reduces Tollens' or Fehling's reagent; glucose, fructose and maltose are examples.
- Addition polymerisation
- A polymerisation in which unsaturated monomers join through their double bonds without eliminating any small molecule, as in the formation of polyethylene.
- Vulcanisation
- The heating of natural rubber with sulphur to form sulphur cross-links between polymer chains, increasing strength, elasticity and resistance to temperature.
- Antiseptic
- A chemical applied to living tissue, such as skin or wounds, to kill or inhibit microorganisms; examples include iodine and dilute phenol.
- Micelle
- A spherical aggregate of soap or detergent molecules in water, with hydrophobic tails pointing inward and hydrophilic heads outward, which solubilises grease.