NABTEB G.C.E CHEMISTRY ANSWERS need our helps and friendship whatapps us on 08105782796 1ai. 1.Temperature 2. Concentration 3. Pressure 4. Surface area of reactants ii. Effective collision 1b. Grahams law of diffusion states that the rate of diffusion of a gas is inversely proportion to the square röot of its vapour density or relative ii. He, CH4 find N2 He = 2, CH4 =16, N2 =28 N2 ---> He because the least relative molecular mass will difuse faster ci. Hard water is defined as the one that does not leather readily with soaps cii. 1. Temporary hardness 2. permanent hardness iii. 1. Boiling 2. Distillation 2ai. In the lower part of the blast furnace, the coke is oxidified by the oxygen in the hot air blast to carbon(iv)oxide C(s) + 02(g) ---> C02(g) on moving up the furnance, the oxygen in the air leassens and the carbon(iv) oxide react with more coke and reduced to carbon (ii)oxide C02(g) + Cs --->2C0 The carbon(ii) oxide then react with iron(iii)oxide and reduce it to iron. Fe203(g) + 3C0(g) ---> 2Fe(l) + 3C02(g) while the function of the limestone is to remove impurities, such as silica in the form of a slag. CaCo3(s) -----> Ca0(s) +C02(g) SiO2(s) + Ca0(s) ---> Casio3(s) aii. CaC03(s) + 2HCL(aq) ---> Cacl2(aq) + H20(l) + C02(g) initial mass = 3.5g, remained mass = 2.5g reacted mass = 3.5 - 2.5 = 1.0g molar mass of marble (Cac03) = 40 + 12 +(16*3) = 40 + 12 + 48 = 100gmol^-1 mole of marble = mass(g)/molar mass = 1/100 =0.01mol 1mole ------ 22.4dm^3 0.01mole ----- y y = 0.01 * 22.4 =0.224dm^3 concentration of marble = mass (g)/volume =0.01/0.224 = 0.0446moldm^-3 rate of the reaction = amount of marble(moldm^-3)/time taken(s) =0.0446 moldm^-3 s^-1/time 2bi. It is because tetraoxosulphate (vi) acid has two replaceable hydrogen ion which make it possible to form acidic and normal salt unlike trioxonitrate(v) acid which has one replaceable hydrogen ion. Ii. Copper reacts readily with H2SO4 because it is one of the passive metals which embraces corrosive ability of acid iii. It is because of their surface area because the more or higher the surface area the fast the rate of chemical reaction. Zinc dust has more surface are than zinc granules. 2c. i. Aluminium, lead(ii) iodide solution and magnessium ii. Hydrogen iii. Magnessium and hydrogen iv. Magnessium di. 1. They exhibit catalytic activities 2. They are complex ions 3. They possess variable oxidation state ii. 1. Sodium 2. Copper 3ai. Hydrocarbon is a compound that contains carbon and hydrogen only 2bii. Two chemical properties of methane 1. It burns in air to produce carbon(iv) oxide and water. It is known as combustion reaction CH4(g) + 202(g) ---> C02(g) + 2H20 2. It reacts with chlorine in the presence of sunlight to produce photocatalyst(chloromethane) CH4(g) + CL2(g) ----> CH3CL(aq) + Hcl ci. Saponification fat or oil + caustic alkali ----> soaps + propane -1,2,3 triol. ii. Esterification Alkanoic acid + alkanol -----> ester + water CH3C00H + C2H50H--- >CH3C00C2H5 + H20 iii. Polimerization 2ncH2 = CH2 ---> (CH2 - CH2 - CH2- CH2)n iv. Neutralization base + acid ---> salt + water NaoH(aq) + Hcl(aq) --- Nacl(aq) + H20 d. C 88.9/12 7.4 7.4/7.4 1 H 11.1/1 11.1 11.1/7.4 2 =1:2 its empirical formula =CH2 4ai. 1. Proton 2. Electron 3. Neutron ii. ZnS04.7H20 relative molecular mass = 65 + 32 + 64 + 7*18 =65 + 32 + 64 + 126 =287 percentage of water of crystallization = 128/287 * 100% = 44.6% bi. Atomic orbital is defined as a diagram which shows or indicates revolvement of electron round the diagram ii. 1. Mx = 100% - 28.9% = 71.1% My = 100% - 21% =79% Mx : My = 71.1 : 79 = 1 : 1 2. Law of multiple proportion c. Four chemical reactions of ethane 1. C2H6 +02 --> C02 + H20 2. C2H6 + Cl2 --> C2H5Cl + Hcl 3. C2H6 + H20 --> C2H50H + H2 4. C2H6 + HN03 --> C2H5N02 + H20 4C. Ii. The electrolysis of brine yields hydrogen and chlorine at the electrodes, and a concentrated solution hydroxide. Using graphite as electrodes at the anode : chlorine is liberated 2CL^-1(aq) ---> CL(g) + 2e^- at the cathode : the sodium ions which are attracted to the cathode form a loose association with the mercury to produce sodium amalgam 2Na/Hg(l) + 2H20(l) ---> 2Na0H(aq) + 2Hg(l) + H2(g) need our helps and friendship whatapps us on 08105782796
Posted on: Thu, 28 Nov 2013 10:48:21 +0000
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