(a) (i) Define nuclear fission.
(ii) A certain natural decay series starts with (^{238}_{92}U) and ends with(^{230}_{90}Th). Each step involves the loss of an alpha or a beta particle. Using the given information, deduce how many alpha beta particpes were emitted.
(b) Consider the equilibrium reaction represented by the following equation:
A(_{2(9)}) + 3B(_{2(9)}) (rightleftharpoons) 2AB(_{3(g)}); (Delta)H = + xkJmol(^{-1})
Explain briefly the effect of each of the following changes on the equilibrium composition: (i) increase in concentrat of B; (ii) decrease in pressure of the system; (iii) addition of catalyst.
(c) The lattice energies of three sodium halides are as follows:
|
Compound |
NaF | NaBr |
Nal |
|
Lattice energy/kJmol(^{-1}) |
890 | 719 | 670 |
Explain briefly the trend.
(d) State the property exhibited by nitrogen (IV) oxide in each of the following reactions:
(i) 4Cu + 2NO(_2) (to) 4CuO + N(_2);
(ii) H(_2)O + 2NO(_2) (to) HNO(_3) + HNO(_2).
(e) Iron is manufacturcd in a blast furnace using iron ore (Fe(_2)O(_3)), coke and limestone. Write the equation for the reaction(s) at the: (i) top of the furnace; (ii) middle of the furnace; (iii) bottom of the furnace.
(f) (i) Name two products of destructive distillation of coal. (ii) Give one use of each product in (f)(i).
Explanation
(a)(i) It is the splitting of a heavy nucleus into smaller nuclei accompanied by the release of large amount of energy.
(ii)(^{238}_{92}U) and ends with(^{230}_{90}Th) + (2^{4}_{2}He) + (2^{o}_{-1e}Th)
(alpha) [articles = 2
(beta) particles = 2
(b)(i) Equilibrium positicn shifts to the right and more of AB(_3) is formed or decrease in concentration of A(_2)
(ii) Equilibrium shifts to the left and more of A(_2) and; B(_2) formed / decrease in concentration of AB(_3)
(iii) No effect. Catalyst affects both forward and backward reactions equally.
(c) For a constant cation Na(^+) lattice energy decreases with ircreases in size of the anion / decrease in electronegativity of the anion.
F(^-), Br(^-), I(^-) increasing order of size. Hence the decreasing crder ofilattice energy.
(d)(i) NO(_2) is an oxidizing agent
(ii) NO(_2) is acting as an oxidizing as well as reducing agents OR acid anhydride.
(e)(i) Fe(_2) O(_3) + 3CO –> 2Fe + 3CO(_2)
(ii) CaCO(_3) —› CaO + CO(_2), CaO + SiO(_2) (to) CaSiO3
(iii) C + O(_2) —> CO(_2), CO(_2) + C (to) 2CO
(f) Coke I Coal Tar / Coal Gas /Ammonical Liquor
(ii) Coke — Solid fuels I production of water gas, extraction of ME Coal Tar — Synthesis of chemicals — perfumes, dyes, paints, drugs, plastic and explosives, etc. Coal Gas — as fuels in homes and industries
Ammonical liquor — production of (NH(_4))(_2) SO(_4) for fertilizer