NECO Chemistry Past Questions & Answer 2017 Essay & Objectives Theory

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NECO Chemistry Past Questions & Answer 2017 essay, Firstly, this is the Past NECO Chemistry 2017 Objectives & Theory answers published for students who is searching for guidelines to pass the upcoming Chemistry examination scheduled for next week.

Sometime last month we published an article on Past NECO Chemistry Practical Specimen 2017 for students writing NECO practical and thousands of students sent us mail to thank us for giving out past questions which they studied before writing the exam.

Similarly,  the Essay & Objectives Theory NECO Chemistry 2017 answers has been published on this page to assist students who wants to use it to study.

WARNING: This is not the current NECO exam answers 2017. DO not use it as expo for examination malpractice because you will fail. Its for study purpose only.

Date for Writing NECO Chemistry Exam 2017: NECO Chemistry Past Questions & Answer 2017 essay

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Chemistry 2 (Essay) Thursday 6th July: 10am – 1pm

Chemistry 1 (Objective) Thursday 6th July: 10am – 1pm

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Chemistry Past Obj Answers: No Questions at all

01 – 10 = ACDBCBDBCA

11 – 10 = DBAADCDBCB

21 – 20 = DBCBCCDBAD

31 – 30 = BACBACBCCD

41 – 50 = BDACABDABD

Chemistry Past Theory Answer: The Questions are not Here

Question 3

1ai) An acid base indicator is a weak acid or weak base that exhibits a colour change as the concentration of hydrogen (H^+) or hydroxide (H^-) ions changes in an aqueous solution

1aii) Methyl-orange

1b)

i) Oxidizing agent

ii) Mixed anhydride

1ci)

Enthalpy of combustion is the heat evolved when one mole of a substance is completely burns in oxygen gas under standard conditions

1cii)

Enthapy of combustion is always negetive since it involvs a rise in temperature and heat of reactants is greater than the heat of products

1d)

Primary cell is a cell that cannot be re charged while secondary cell is a cell that can be recharged

1dii)

primary cell — daniell cell

secondary cell — lead accumulator

1e)

Mole is the unit of measurement in the International System of Units (SI) for amount of substance. The unit is defined as the amount of a chemical substance which contains as many representative particles, e.g., atoms, molecules, ions, electrons, or photons, as there are atoms in 12 grams of carbon-12 (12C), the isotope of carbon with relative atomic mass

1f)

n= V=40cm^3

c= 0.40moldm^3

n=cv/1000

0.40*40/1000 = 0.016mol

1g)

i) Platinum

ii) Carbon

1h)

i) Hydrogen bonds

ii) Vander waals forces

1i) Water(H2O) and Carbonmonoxide (Co)

1j) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^3 4s^2

2017 NECO Chemistry Questions and Answer Expo

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Question 3

3b)

In other words the oil is stained red. This is a specific test for fats if suden (iii) is added to fats a distinct red colouration is observed

3c)

Given 2502+02+2H20—>2H2SO4

1mole produce 2mole

1.3mole produce 3mole

moles of H2SO4=3mole

molar mass of H2SO4=(1+2)+32+(4*16)

=2+32+64 = 98gmol-^1

mole=mass/molar mass

mass and H2SO4=Mole*molar mass

=3*98 =294g

3di) DH2

Question 4

4ai) Thermal cracking

4aii) C4H8

4aiii) 

(I) H H. H

| | |

H-C-C-C=C

| | | |

H H H H

and

(II) H H

| |

H-C-C=C-C-H

| | | |

H H H H

NECO Chemistry Past Questions & Answer 2017 | Essay & Objectives Theory

4aiv)

I-normal butene

II -But-2-ene

Ni

4av)

C4H8 +H2 ——-> C4H10

250c

4b)

method

– rub the fat on a blank white paper

– pour Sudan (III) dye over the paper

-wash the paper under tap

Observation

– rubbing the fat on the paper produces a translucent color

-pouring sudan (III) will stain the blot red

Conclusion

– fat is present because sudan (III) can stain fat red

Question 5

5bi)

C(s) + O2(g) =====> Co2(g)

Co2(g) + C(s) =====> 2Co(g)

Fe2O3(s) + 3Co(g) =====> 2Fe(l) + 3Co2(g)

The limestone present decomposes as follows:

CaCo3(s) =====> CaO(s) + Co2(g)

Which is available to remove silicon(iv) oxide impurity

SiO2(s) + CaO(s) =====> CaSiO3(s)

5bii)

Faraday’s first law of electrolysis states that, the mass (m) of an element discharged during an electrolysis is directly proportional to the quantity of electricity (Q) passing through it.

NECO Chemistry Past Questions & Answer 2017 essay

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