Chemistry

Chemistry Section 15 The ground state is the lowest energy state of an atom, while excited states have higher energy. Absorption and emission spectra are used to identify the elements present in a sample. Electromagnetic radiation is emitted when electrons transition from higher energy levels to lower energy levels. The principal quantum number (n) specifies […]

Chemistry Section 14 The correct atomic weight sequence is Co > Ni > Fe. The limit of the visible spectrum is 3800 to 7600 A°. The wave-number of the second line in the Lyman series is 3R/4. The magnetic quantum number specifies the orientation of orbitals. The azimuthal quantum number defines the angular momentum of

Chemistry Section 13 50% inversion of configuration of molecules takes place in SN1 – reaction. The alkyl halide with the highest reactivity for a particular alkyl group is R-I. H3C+ is not a nucleophile. Among the given alkyl halides, (CH3)2 CH – X can follow both SN1 and SN2 mechanisms. When two moles of ethyl

Chemistry Section 12 Phosphoric acid can be produced by the reaction of PCI5, P2O3, and P2O5 with water. “Phosphorus” is derived from a Greek word meaning “Light bearing.” The poisonous allotropic form of phosphorus is “White phosphorus.” Acetic anhydride can be obtained by treating ethyl alcohol with P2O5 and H2SO4. Thermal decomposition of phosphorous acid

Chemistry Section 11 In base-catalyzed carbonyl reaction, catalyst increases nucleophilic character. Alkali metals are named due to basic oxide and hydroxides solubility. Formula of Chile saltpetre is NaNO3. Beryllium oxide (BeO) is amphoteric. Li differs due to small size, high charge density, and less electropositivity. Carbonates of lithium are unstable due to low electropositivity. Radium

Chemistry Section 10 An element with electronic configuration 1s2 2s2 2p2 belongs to Group IV-A. Among the given ions, Cl- is stable in aqueous solution. Atoms of the same element with the same atomic number but different mass numbers are called isotopes. Shielding effect across a period remains constant. A higher value of electron affinity

Chemistry Section 9 Lipids are soluble in organic solvents. Animal and vegetable fats are triesters formed from glycerol and fatty acids. Triglycerides are easily hydrolyzed by enzymes called lipases. Saponification is the hydrolysis of fat or oil with an alkali. Enzymes from the same organism that catalyze the same reaction but are chemically distinct are

Chemistry Section 8 Compounds with added water molecules are called hydrates. A solution of Na2SO4 will be neutral. A 1 molar solution of glucose in water contains a weight of 180g/dm3 of glucose. Water of crystallization can be removed by heating. Na2SO4 is a salt that does not hydrolyze. Molality is the concentration unit independent

Chemistry Section 7 The state of matter with the lowest density is gas. Solid particles only possess vibrational motion. Plotting 1/V on the X-axis and pressure on the Y-axis results in a straight line. One mole of an ideal gas at 546.5 K and 2 atm pressure has a volume of 22.414 dm3. None of

Chemistry Section 6 An exothermic reaction releases heat energy to the surroundings. An endothermic reaction absorbs heat energy from the surroundings. The activation energy is the energy required to initiate a chemical reaction. A catalyst increases the rate of a chemical reaction by lowering the activation energy. The rate of a chemical reaction is the