Neco 2016 CHEMISTRY (Obj And Theory) Answers – May/ July Expo Share This On Facebook

Obj Shall b€ uploaded by 9:30am Start Paying For Your Maths Now To Be Added To get Early delivery on time. ================================ MATHS RUNS Direct inbox N1,000 password N600 Send Your MTN Card, Subject, Phone Number To 08137827641 fully Solved Answers get to you 1am midnight ================================ Warning Dont send your payment details twice to the Above number else your payment will be invalid and you will not get the password. Be warned!!!. ================================ Chemistry-Answers ================================ (1ai) A mixture contains two or more constituents which can easily be seperated by physical methods (1aii) magnesium trioxonitrate(v) = Mg (NO3)2 molar mass of Mg(NO3)2 =(1*24) + 2 (14*1 + 16*3) =24 + 2 (14 + 48) =24 + 28 + 96 = 148g/mol % of nitrogen = 2*24*100/148 % of nitrogen = 48*100/148 % of nitrogen = 4800/148 % of nitrogen = 32.43% (1aiii) (i)calcium oxide (CaO) (ii)calcium choride (CaCl2) (1bi) CnH2n+1OH (1bii) hydrolysation (1biii) (i)displacement reaction (ii)double decomposition reaction (iii)decomposition reaction (iv)catalytic reaction (v)reversible reaction (1biv) (i)endothermic heat change (ii)exothermic heat change (1ci) (i)methyl orange (ii)phenolphthalein (iii)litmus (1cii) NH4Cl+Ca(OH)2----- >CaCl2+2NH3+2H2O (1ciii) it is collected by upward delivery (1civ) mass of gas = 1.58*22.4 = 35.392 vapour density = 35.392/1 relative molecular mass= V . D * 2 =35.392*2 relative molecular mass= 70.784 ================================ (2ai) ionization energy deals with electron loss while electron loss while electron afinity deals with electron gain (2aii) (i)they are used to dry gases (ii)they are used to recover valuable vapours from industrial effluents and refine petroleum (2bi) TABULATE: -RHOMBIC SULPHUR- (i)bright yellow in colour (ii)it is octohedral in shape -MONOCLINIC SULPHUR- (i)amber in colour (ii)it is needle like in shape (2bii) oxygen = 60% sodium = 40% oxygen 60/16 3.75/1.74 = 2 sodium 40/23 1.74/1.74 = 1 the emperical formula is NaO2 (2biii) sodium(iv)oxide (2ci) (i)x is hydrophobic region (ii)y is hydrophilic religion (2cii) (i)for laundry purpose (ii)for fuel (2ciii) (i)the distance of outermost electron from the nucleus (ii)the size of the positive nuclear charge (iii)the screening effect of inner electrons (2civ) period law states that the properties of the elements are a period function of their atomic number (2di) n---pentane----->n---butane----->2--- methylbutane---2,2--- dimethylpropane (2dii) (i)glucose (ii)galactose ================================ 4ai) electrolytic cell is a cell that consist of a container of electrolyte with two electrodes connected to a suitable direct current supply 4aii) i)daniel cell ii)Leclanché cell 4aiii) i)copper ii)tin 4aiv) action of dilute acide on zinc 4av) Zn+2HCl------>ZnCl+H2 4bi) i)dinitrogen(i)oxide(N2O) ii)nitrogen(v)oxide(N2O5) iii)nitrogen(iv)oxide(NO2) 4bii) charle's law states that the volume of a fixed mass of gas varies directly with the absolute(kelvin)temperature provided the pressure remains constant. 4biii) P1 V1 = P2 V2 given that P1 = 900mmHg P2 = 750mmHg V1 = 300cm^3 V2 = ? V2 = P1V1/P2 V2 = 900*300/750 V2 = 270000/750 V2 = 360cm^3 4biv) % composition carbon = 12/(12*6) + (1*6) *100% = 12/72+6 *100 = 12/78 * 100% = 1200/78% %composition of carbon = 15.38% 4c) TABULATE -THERMOPLASTS- i)it melts when heat is applied to it ii)highly recycled -THERMOSETS- i)does not melt when heat is applied ii)cannot be recycled ================================ 5ai) i)carbon monoxide and hydrogen ii)carbon monoxide,carbon dioxide,hydrogen and nitrogen 5aii) i)colloids is an intermediate between true solution and a suspension ii)condensation is the process by which water vapour in the air is changed to liquid water 5bi) CaC03+2HCl----->CaCl2+H2O+CO2 5bii) i)it is used in fire extinguishers ii)it is used in the manufacturing of mineral water iii)carbon(iv)oxide is used as a coolant in nuclear reactors 5biii) i)Cr2O7^-2 =2Cr + C-2*7) = -2 2Cr - 14 = -2 2Cr = -2 + 14 2Cr/2 = 12/2 Cr = 6 ii)Cr2{SO4}3 2Cr + 3 (-2*1 + -2*4) = 0 2Cr + 3 (-2 - 8) = 0 2Cr + 3 (-10) = 0 2Cr - 30 = 0 2Cr/2 = 30/2 Cr = 15 5ci) vulcanization is a chemical process of converting netural rubber or related polymers into more durable materials through the addition of sulphur or other equivalent curatives or accelerators 5cii) Time Taken(t) for 6.35g of copper (ii)tetraoxosulphate solution Cu^2^+ + 2c ------->Cu Q = 2*63.5*95600 Q = 12255500 Q = 1t 12255500/10 = 10*t/10 t = 1225550/60 = 204258.3 5ciii) Latex ================================ U Like It? Kindly Drop Your Comments Below& Hit Share