Neco Gce 2016 Chemistry Obj And Theory Answers – Nov/Dec Expo

CHEMISTRY OBJ
1CDCCEBBBCB
11EADBCAECDD
21ECDCACAEAB
31DDDBAABBCD
41CDCBCDCDCA
51CEEEEBCBBB

1ai)
i)1s^2 2s^2 2p^6 3s^2 3p^5
ii)halogens.
ii)iodine (531) has the Existing ability

1aii)
i)by Electroplanting the Iron
ii)by painting the iron
iii)by lubricating the iron

1bi)
Geometric Isomerism is the existences of compound with the same muscular formular but are not identical because different spatial arrangement of the compound atoms

1bii)
H H
I I
Cl- c- c- Cl
I I
H H
1,2 dichlorine ethane
2,2 dichlorine ethane

1biii)
when the concentration decreases the conductivity of electrolytes increases.

1ci)
total moles =3+3+2=100
Moles fraction of Nitrogen=2/10=1/5

1cii)
the law of definite proportion

1ciii)
The law of definite proportion states that all pure samples of a particular chemical compound contains similar elements combination remain the same proportion By mass.

1civ)
i)Sieving
ii)Sublimation

1di)
Zn+AgNo3 ZnNo3+Ag

1dii)
Zinc id oxidized

1diii)
Ag (solvent) is Reduced

2ai)
**Component of producer gases are the mixture of flammable gases (principally carbon monoxide and hydrogen) and nonflammable gases (mainly nitrogen and carbon dioxide) made by the partial combustion of carbonaceous substance.

**Component of water gas Water gas is produced from synthesis gas, which is composed of carbon monoxide and hydrogen. Syngas is a useful product but requires careful handling due to its flammability and the risk of carbon monoxide poisoning

2ci)
amorphous form of carbon include:
i)Wood charcoal
Ii)Animal charcoal
iii)Soot
iv)Lamp block

2cii)
uses of diamond
I)it is used in making jewelry
ii)it is used in cutting glass

3ai)
Hydrocarbons are compound of hydrogen and carbon only.

3b)
i)carbon(iv)oxide co2 react with water I.e dissolves in water to form trioxocarbonate(iv)acid (soda water) which is a weak diabasic acid while carbon(ii)oxide react with Oxygen I.e burns in AIT with a faint blue flame forming carbon (ii)oxide
ii)co2 react with red hot carbon I.e if co2 is passes over a red -hot carbon,it is red used to carbon(iv)oxide while carbon (ii)oxide react with haemoglobin

3ci)
i)T
ii)S
iii)P
iv)Q

3cii)
electrovalent bond

3di)
spin quantum number
Ii)principal quantum number
ii)magnetic quantum number
iv)azimatal quantum number

3dii)
addition polymerization
Condensation polymerization

4ai)
1)Esterification involves the reaction between an alkanol and alkanoic acid while neutralization involves an acid and a base.
2)Esterification produces ester and water as product while neutralization produces salt and water only.

4aii)
i) petroleum
ii)diesel
iii) kerosene

4bi)
The rate of a chemical reaction can simply define as change in concentration over the change in time and is a metric of the “speed” at which a chemical reactions occurs

4bii)
Collision theory, theory used to predict the rates of chemical reactions, particularly for gases. i.e The collision theory is also based on the assumption for a reaction to occur it is necessary for the reacting species (atoms or molecules) to come together or collide with one another.

4d)
i)Catalytic cracking
ii)Thermal cracking

5bi)
in Fats:
are solid at room temperature
made by animals, mostly
are more saturated.

In Oils:
are liquid at room temperature
are made by plants, mostly
are less saturated.

5bii)
i)Ethanoic acid is vinegar smelling liquid. The lower carboxylic acids are liquids whereas higher ones are solids.
ii)Ethanoic acid is sour in taste. Other lower carboxylic acids are also sour in taste.
iii) Ethanoic acid has boiling point 391 K. Carboxylic acids have higher boiling points than corresponding alcohols, aldehydes and ketones.
iv) Acetic acid is soluble in water, i.e., it is miscible with water in all proportions. The lower carboxylic acids are soluble in water but solubility in water decreases with increase in molecular weight.

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