Verified 2017 Neco GCE Chemistry Obj & Theory Answers

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100% VERIFIED CHEMISTRY OBJ ANSWERS
1-10: AAEBBDCAAC
11-20: ABBEBDDBCD
21-30: BABDCECEEC
31-40: CBDEBBBCBB
41-50: AECBBEDBDE
51-60: ACEBDCCEDB
100% VERIFIED CHEMISTRY THEORY ANSWERS
2a)
(i) Temporary hardness – Dissolved calcium hydrogencarbonate
(ii) Permanent hardness -Dissolved calcium sulfate.
(2bi)
(i) Temporary Hardness can be Removed By Boiling
(ii) Permanent hardness can be removed by use of washing soda (sodium carbonate); ion exchange; the use of polyphosphate water softeners.
(2bii)
-Advantages:
(i) Calcium ions in the water are good for children’s teeth and bones.
(ii) The soothe it forms is good for ceramics purposes.
-Disadvantages:
(i) It is more difficult to form a lather with soap.
(ii) Scum may form in a reaction with soap, wasting the soap.
(2ci)
A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent.
(2cii)
(2ciii)
(i) Anthracite Coal
(ii) Bituminous coal
(iii) Subbituminous coal
(2civ)
Coal tar
(2di)
(i) Zinc is not a transition metal because it forms only Zn2 ions with all the 3d electrons present.
(ii) Zn not a transition metal, because it forms only Sc3 ions with n d-electrons
(2dii)
Fine chemicalChemical substances prepared to a very high degree of purity for use in research and industry.
(2diii)
(i) dyes
(ii) perfumes

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(3ai)
Petroleum Gas and Petrol>Kerosene>Diesel>Asphalt 
(3aii)
I. Asphalt 
II. Kerosene
III. Petroleum Gas and petrol 
Iv. Asphalt 
(3bi)
I. Ethene
II. Propene 
(3bii)
(i) Structural Isomerism 
(ii) Stereo Isomerism 
(3biii)
19R – 1s² 2s² 2p6 3s² 3p6 4s¹
10S – 1s² 2s² 2p6
24T – 1s² 2s² 2p6 3s² 3p6 4s² 3d4
(3biv)
Group 6
(3ci)
I. AgNO3 and BaCl2
II. Bacl2 and Na2SO4
III. Ca(NO3)2 and H2CO3
(3cii)
(i) Filtration 
(ii) Flocculation
(iii) Disinfection
(3d)
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