Chemistry Neco 2015 Answers Available Now!!!

By 01:36 Tue, 16 Jun 2015 Comments


=============================================

Wednesday 17th June Paper III & II: Objective

& Essay –

Chemistry – 10:00am – 1:00pm

OBJ TYPE C

1B-The collision between the gas molecules

2A-1s^22s^22p^63s^23p^5

3B-negatively charged ion

4D-High pressures

5C-40

6D-I^-(aq)

7A-addition reaction

8A-can reach completion and by changing the conditions can go back to give the starting substances as products

9D-K^+

10A-calcium hydrogen trioxocarbonate(iv)is decomposed by heat

11D-Monoclinic

12D-Tetraoxosulphate(vi)acid

13A-chromatography

14E-separating funnel

15D-Have the same number of valence electrons

16D-The distance between the comparison

17A-acid

18E-SO4^2-

19D-2.24

20C-210.2

21C-oxidation

22C-benzophenol

23E-methyl propanoate

24D-zinc

25A-cooordiate covalent

26D-increase

27B-16.2

28B-beryllium and boron

29B-m proportional as It

30B-electrons

31A-hydrogen and chlorine

32D-(-15)

33C-oxidation power

34A-H2S

35D-oxidation number

36D-iron

37D-6

38E-thermal oxidation

39B-150

40B-boyle's

41C-nature reactants

42A-H2O(l)->H2O(s)

43D-hydrogenation

44C-C4H10

45B-calcium

46A-brass

47B-carbon

48A-K2CO3

49B-32

50C-lactic

51B-monobasic

52D-Trioxonitrate(V)

53E-(238)(92)U

54C-helium

55D-54

56D-lithosphere

57C-efflorescence

58C-2,3-dimethylhexane

59B-glucose

60A-fructose

Chem-Type A

1-10: AEDBAEABCD

11-20: AACCAAEAAE

21-30: AADDBBADAA

31-40: DABADDACAD

41-50: ADBCEED - BB

51-60: ADCDEDCDED

==================

CHEMISTRY OBJ obj type c

1-10. BABDCDAADA

11-20.DDAEDDAEDC

21-30. CCEDADBBBB

31-40. ADCADDDEBB

41-50. CADCBABABC

51-60. BDECDDCCBA

===================

chem-Type D

1-10: CDAAAEABAE

11-20: DDCACDCCAA

21-30: EED - ADBCAE

31-40: DBADDCADAA

41-50: ACBDAADDCB

51-60: ECCDECBBCD

1a. Physical change

i. It is easily reversible.

ii. No new substance are formed.

iii. There is no change in the mass of a substance involved in

such a change.

iv. It does not involve any great heat change except the heat

changes which occur during changes of state, e.g the heat of

dissolution and the latent heats of fusion and vaporization.

CHEMICAL CHANGE.

i. It is not easily reversible.

ii. Entirely new substances are always produced.

iii. there is a change in the mass of a substance that

undergoes such a change.

iv. A considerable amount of heat change is usually involved.

1ii)

GASES DENSER DAN AIR IS THROUGH

DOWNWARD DELIVERY

ii)LESS dense,upward delivery

Gases insoluble and less dense

-Collection by water

1bi) HCL gas and ammonia gas

1bii) highly soluble in water

1biii)

==> Compound:

I) Element are chemically combined

II) It is homogeneous

==> Mixture:

I) Are physically combined

II) It is heterogeneous

1ci) An isotope is a form of a chemical element

whose atomic nucleus contains a specific

number of neutron s, in addition to the

number of proton s that uniquely defines

the element.

The nuclei of most atom s

contain neutrons as well as protons. (An

exception is the common form of hydrogen,

whose nucleus consists of a lone proton.)

Every chemical element has more than one

isotope.

1cii)

=> Atomic Mass(x) | 35 , 37

=> R.abundance (f) | 75 + 25 = 100

=> Atomic by R.A(fx) | 2625 , 925

Total of (Fx) = 2625 + 925 = 3550

RAM = 3550/100

= 35.5

"Note: they are in tabular form

The sign (,) means Next line"

1ciii) Hudrogen gas , tetrachloromethane,methane

1civ)

I) High boiling point and Melting points

ii) Soluble in water & insoluble in organic solvent

(2ai)

Ionization energy

(2aii)

Atomic radius

(2aiii)

Ionization energy increases across the period because the number of electronic shell increases

Atomic radius iincreases because the number of increases

(2aiv)

-Diffusion

-Brownian motion

-Osmosis

(2bi)

Gay lussac's law of combining volume states that the volumes of gases which take part in a chemical reaction bear a simple ratio to one another and to the volume of the gases

(2bii)

Given; nN2=0.64

nCO2=0.5

nO2=0.375

PT=PN2+PCO2+PO2

Molar mass of N2=14*2=28

Molar mass of CO2=12+16*2=44

Molar mass of O2=16*2=32

PN2=(nN2/(nN2+nCO2+nO2))PT

PN2=(0.64/(0.64+0.5+0.375))*760

PN2=(0.64/1.515)*760

PN2=321'mmHg

PCO2=(0.5/1.515)*760

=251mmHg

PO2=(0.375/1.515)*760

=188mmHg

(2ci)

The basicity of an acid is the number of replaceable hydrogen ion in one molecule of an acid

(2cii)

Tetyraoxosulphate(vi)acis is corrosive because its concentrated form causes serious burnt

(2ciii)

Acid salts-KHCO3

Basic salt-Na2CO3

(2di)

Deliquescence substance is a substance when exposed to the atmosphere absorb water from the atmosphere and suddenly turn to solution

(2dii)

Calcium

3a)

Diamond

-Diamond is tetrahedral in nature

-Diamond is the hardest substance

Graphite -Graphite is a crystalline solid

-Graphite has a low melting point

3b)

-Limestone is used to produce the carbon

( iv ) oxide

-Ammonia is used as catalyst

3ci)

Heavy chemicals -> Dye

Fine chemicals -> H2SO 4

3cii )

I- The higher the surface area of

reactants, the higher the rate of

reaction . Reactants in powered form

reacts faster than solid form

II -Catalyst helps to speed up the rate of

chemical reaction

III -Temperature ; The higher the

temperature of reacting vessels ,the higher the

rate of reaction

3d)

-Because they have i 8 ncompletely filled

3d- orbital

-Because they exhibit co-ordinate bond

between molecules -Because they have

magnetic domain

3e)

-Natural gas; It is used for cooking

-Bitumen; It is used for candle wax

5ai)

-Evaporation

-Combustion

-Carbon cycle

5aii )

I- Cathode is the negative electrode

through which current enters . Anode is

the positive electrode through which current

leaves

II -Conductors are solids which allow the

passage of electricity . Electrolyrtes are

solutions which conduct electricity

III -Strong acid is the acid which ionizes

completely in water. Concentrated acid is the

acid which contains no water dilution

5bi)

Mass of copper( m )= MQ /nF

0. 16 =( 63. 5* Q) /( 2* 96500 )

Q=( 0 . 16* 2* 96500 ) /63. 5

Q=486 . 30 Q =I* t

48i 6. 30 =I* ( 15* 60)

I=486 . 30 /900

I=0 . 54A

5bii )

Burning : oxygen is not required for burning while

Rusting : oxygen is required

for rusting

5biii )

-By electrolysis

-By putrification of ores

5ci) Sulphur

5cii )

-Bauxite

-Cryolite

5ciii )

-It speeds up the rate of chemical reaction

-It is not used up in reaction

----------------------COMPLETED-----------------------


DOWNLOAD NOW

DOWNLOAD MUSIC





Related Article

Comment
Name




.....................

Please LOGIN or REGISTER To Gain Full Access To This Article