1a) nucleons is the collective name for two important sub-atomic particles:neutrons and protons
1b) Graham's law of diffusion states that at a constant temperature and presure,the rate of diffusion of a gas is
inversely proportional to the square
root of it density
1c)
because when aluminum is exposed to
moist air,a thin continuous coating of
aluminum oxide is formed, which
prevents futher attack of the aluminium
by atmospheric oxygen and water or
steam under normal conditions
1d)
i) electron - affinity
ii) electron - negativity
iii) ionization - energy
1e)
i) the molecule of real gases occupies
space and there are forces of the
attraction between them
ii) real gases do liquefy when their
temperature droops.
1f)
i)used in seperation of different
component of crude oil.
ii)it is used for separating acetonic
from water
iii) it is used for obtaining different
gases from air for industrial use.
1g)
i)concentration of ions in electrolyte
ii)the nature of the electrode
iii)the position of ions in the
electrochemical series
1h)
i)substitution reaction
ii)addition reaction
1i)
i)carbon dioxide
ii)water vapour
iii) carbon monoxide
1j)
i)centrifugation
ii)sieving
iii)evaporation to dryness
==============================
====
2a)
i) isotopy
ii) they have the same number of
proton (atomic number) but different
mass number
iii) oxygen,carbon
iv)1s^2,2s^2,2p^6,3s^2,3p^5
2bi)
PHYSICAL PROPERTIES
METAL
i) high melting and boiling point
ii) they are good conductor of heat and
electricity
NON-MATEL
i)they have lower melting and boiling
point
ii)they are poor conductors of heat and
electricity.
CHEMICAL PROPERTIES
METAL
i) they form basic and ampheric oxides
ii)the react by electron lose or donation
of electron
NON-METAL
i)the form acidic oxides
ii)the react by sharing and accepting
electrons
2bii)
i) Al2 O3(Aluminum oxide)
ii) sodium hydride (NaH)
iii)zinc trioxocarbonate(iv)ZnCo3
iv)silicon tetrachloride (SiCl4)
2ci)
i) variable oxidation states
ii) complex ion formation
iii) they possess strong metallic
bonding
2cii)
1s^2,2s^2, 2p^6, 3s^2, 3p^6, 3d^10,
4s^2
2ciii)
Zinc is not considered as a typical
transition element bacause it has only
one oxidation state of +2, it metallic ion
are not coloured and it is not used as a
catalyst.
2d)
Na2Co3 + MgCl2 ---->2NaCl + MgCo3
1mole 1mole 2mole 1mole
molar mass of Na2 Co3 = 2 * 23 + 12 *
1 + 16 * 3 = 46+12+48 = 106g
==============================
====
5ai)
Na2S2O3 ===>2 + 2x + 6 = 0
2x = 6 - 2 = 4
X = 4/2
X = 2
The oxidation number of sulphur is 2
5aii)
Rhombic&monoclinic
5aiii)
- Both are tetravalent
- both are allotrope of carbon
5bi)
CO2&Chloroflorocarbon
5bii)
There is increase in sun radiation
reaching the earths surface ie Global
warming
5biii)
ThunderStorm
5iv)
I2KNo3. -------->2KNO3 + O2
2AgNo3 --------->. 2Ag + 2No
5ci)
Calcium chloride in a solution can give
rise to crystal using
filteration&evaporation to dryness. The
sol is filtered into filtrate&residue b4
evaporation to dryness takes place.
5cii)
- Because of presence of hydrogen
bonding in NH3
- Because Iodine as higher molecular
mass than chlorine
5di)
Mol of Nacl = Mass / MM
= 5.85/ 58.01
= 0.1mol
From the equation
2mol of Nacl gives 2mol of HCL, 0.1mol
of Nacl gives 0.1mol of Hcl
Vol of Hcl = 0.1 x 22.4 = 2.24mol/dm^3
==============================
No 3
(I) % of carbon = 100 - 14.3 =85.7%
=> C/12.0 , 4/1.0
=> 85.7/12.0 , 14.3/1.0
7.142. , 14.3
Decide both sides by the smallest
7.142/7.142. , 14.3/7.142
1. , 2
=> E. F =CH2
II) (CH2)n = molar mass
But n =volume /molar mass
2.24/22.4 = 0.1mol
Molar mass = mass/amount = 7.0/0.1 =
70g/mol^-1
3ai)
structral isomerism is the existance of
two or more compounds ( known as
isomers) with the same molecular
formula but different molecular
structures
3ai)
i) tertiary alkanol
ii) secondary alkanol
iii) primary alkanol
3bi)
i) 2[CH3 CH2 COOH ] 2K(s)---->
ii) [CH3 CH2 COO ] K + H2
i) 2[CH3 CH2 COOH ] +2 K(s) ------>
2[ CH3 CH2 COO ] K + H2
ii) CH3 CH2 COOH + C4 H9OH
HEAT---->CH3 CH2 COO C4 H9 + H20
H2SO4
iii)CH3 CH2 CH2 CH20H + H^+
KMnO4------> CH3 CH2 CH2 CH2 - 0H
EXCESS
3bii)
i) potassium ethanoate,hydrogen
ii) butyl propanoate and water
iii) enthanal
3c)
the percentage composition of the
hydrocarbon
= 100
H + C = 100
14.3 + C =100
C= 100 - 14.3
C= 85.7%
==============================
====
(4ai)
calcium chloride, CaCl2
(4aii)
to the unknown ssubstance in a gas
jar, add
small quantity of lime water. if the gas
is carbon
(iv)oxide, it turns lime water milky
while carbon
(ii) oxide has no effect
(4bi)
oxygen is releasedf abundantly from air
and
nitrogen is produced by the reaction of
potassium trioxonitrate(v) with
concentrated
hydrochloric acid
(4bii)
oxygen gas rekindle a lighted splint
while
nitrogen does not
(4ci)
Bauxite is preferred because it is
readily
available in the earth crust
(4cii)
-trioxosilicate(iii)
-carbon(iv)oxide (4ciii)
-it helps to purify the bauxite
(4civ)
it is difficult to extract aluminium by
chemical
reduction of aluminium oxide in
amphoteric
(4cv)
AL2O3+NaOH=>Na2O + Al+ H20

CHEM-OBJ
1-10 caacabcdbc
11-20 babaadbdca
21-30 bccaabcdcb
31-40 abcbcccbbc
41-50 abdbbbaabb

Thank's for read our article WAEC 2016/2017 CHEMISTRY QUESTIONS AND ANSWERS
Created at 2016-04-18 05:20:24
Tags: 2016 , 2017 , answers , Chemistry , questions , Waec

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