Chemistry obj
1-10 caacabcdbc
11-20 babaadbdca
21-30 bccaabcdcb
31-40 abcbcccbbc
41-50 abdbbbaabb 3 ai)
structral isomerism is the existance of two or more compounds ( known as isomers) with the same molecular formula but different molecular structures
3 ai)
i) tertiary alkanol
ii) secondary alkanol
iii ) primary alkanol
3 bi )
i) 2 [ CH 3 CH 2 COOH ] 2K ( s) - - - - >
ii) [ CH 3 CH 2 COO ] K + H 2
i) 2 [ CH 3 CH 2 COOH ] +2 K ( s) - - - - - - > 2 [ CH 3 CH 2 COO ] K + H 2
ii) CH 3 CH 2 COOH + C 4 H 9 OH
HEAT- - - - > CH 3 CH 2 COO C 4 H 9 + H 20
H 2SO 4
iii )CH 3 CH 2 CH 2 CH 20 H + H ^ +
KMnO 4- - - - - - > CH 3 CH 2 CH 2 CH 2 - 0 H
EXCESS
3 bii )
i) potassium ethanoate,hydrogen
ii) butyl propanoate and water
iii ) enthanal
3 c )
the percentage composition of the hydrocarbon
= 100
H + C = 100
14. 3 + C = 100
C = 100 - 14. 3
C = 85. 7%
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1 a )
nucleons is the collective name for two important sub - atomic particles :neutrons and protons
1 b )
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
1 c )
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
1 d )
i) electron - affinity
ii) electron - negativity
iii ) ionization - energy
1 e )
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 .
1 f )
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 .
1 g )
i) concentration of ions in electrolyte
ii) the nature of the electrode
iii )the position of ions in the electrochemical series
1 h )
i) substitution reaction
ii) addition reaction
1 i )
i) carbon dioxide
ii) water vapour
iii ) carbon monoxide
1 j )
i) centrifugation
ii) sieving
iii )evaporation to dryness
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2a )
i) isotopy
ii) they have the same number of proton ( atomic number ) but different mass number
iii ) oxygen ,carbon
iv )1 s^ 2 ,2 s^ 2 ,2 p ^ 6 ,3 s ^ 2 ,3 p ^ 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) Al 2 O 3 ( Aluminum oxide)
ii) sodium hydride ( NaH)
iii )zinc trioxocarbonate (iv ) ZnCo3
iv )silicon tetrachloride (SiCl 4 )
2ci )
i) variable oxidation states
ii) complex ion formation
iii ) they possess strong metallic bonding
2cii )
1 s ^ 2, 2s ^ 2, 2 p ^ 6 , 3 s ^ 2, 3 p ^ 6 , 3 d ^ 10 , 4 s^ 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 )
Na 2Co 3 + MgCl 2 - - - - > 2 NaCl + MgCo3
1 mole 1 mole 2mole 1 mole
molar mass of Na 2 Co 3 = 2 * 23 + 12 * 1 + 16 * 3 = 46+ 12+48 = 106 g
106 g of Na 2 Co 3 produced 84 g of MgCo 3
; 106 g = 84 g
xg = 3 . 36 g
84 * x = 106 * 3 . 36
x = 106 * 3 . 36 / 84
x = 356 . 16 / 84
x = 4 . 24 g
4. 24 g of Na 2 Co 3 is needed to produce
3 . 36 g of MgCo 3
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5 ai )
Na 2S 2 O 3 ===> 2 + 2 x + 6 = 0
2x = 6 - 2 = 4
X = 4 /2
X = 2
The oxidation number of sulphur is 2
5 aii )
Rhombic & monoclinic
5 aiii )
- Both are tetravalent
- both are allotrope of carbon
5 bi )
CO 2 & Chloroflorocarbon
5 bii )
There is increase in sun radiation reaching the earths surface ie Global warming
5 biii )
ThunderStorm
5 iv )
I 2 KNo3 . - - - - - - - - > 2KNO 3 + O 2
2AgNo 3 - - - - - - - - - > . 2 Ag + 2No
5 ci )
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 .
5 cii )
- Because of presence of hydrogen bonding in NH 3
- Because Iodine as higher molecular mass than chlorine
5 di )
Mol of Nacl = Mass / MM
= 5 . 85/ 58 . 01
= 0 . 1 mol
From the equation
2mol of Nacl gives 2mol of HCL, 0 . 1 mol of Nacl gives 0 . 1 mol of Hcl
Vol of Hcl = 0 . 1 x 22 . 4 = 2. 24 mol /dm ^ 3
(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
