NECO Chemistry Questions and Answers 2018 | NECO OBJ & Theory Answers.
NECO Chemistry Questions and Answers 2018 | This page contains list of Chemistry Questions that will be asked for the June/July 2018 Chemistry Examination. Stay focus and read through.
NECO Chemistry Questions and Answers 2018.
The National Examinations Council is an examination body in Nigeria that conducts the Senior Secondary Certificate Examination and the General Certificate in Education in June/July and December/January respectively.
Possible Chemistry Practical Questions
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CHEMISTRY OBJ :
1-10 DCBBCBBEDC
11-20 CADECEBBDC
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
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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
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