¶¶ Neco Gce 2017 Chemistry Obj And Essay Solution Answer – Nov/Dec Expo

WELCOME TO AYOSTUFFS GCE CHEMISTRY PORTAL
+++++++++++++++++++++++++++++++++++
REFRESH THIS PAGE EVERY 5MIN
++++++++++++++++++++++++++++++++

CHEMISTRY OBJ

1-10: AAEBBDCAAC

11-20: ABBEBDDBCD

21-30: BABDCECEEC

31-40: CBDEBBBCBB

41-50: AECBBEDBDE

51-60: ACEBDCCEDB

​====COMPLETED====​

2a)

---Temporary hardness is caused by dissolved calcium hydrogencarbonate 

---Permanent hardness is caused by dissolved calcium sulfate.

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

2bi) 

---Temporary Hardness can be Removed By Boiling

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

---Permanent hardness can be removed by ... washing soda (sodium carbonate); ion exchange; the use of polyphosphate water softeners.

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

2bii) 

 ​Advantages​ 

---Calcium ions in the water are good for children's teeth and bones. 

---Some brewers prefer using hard water for making beer.

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

2biii) 

 ​Disadvantages​ 

---It is more difficult to form a lather with soap.

---Scum may form in a reaction with soap, wasting the soap.

=======

2c)

A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent.

2cii)

Solving..... ✍🏽✍🏽

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

2ciii) 

---anthracite Coal

---bituminous coal

---subbituminous coal

2civ) 

The anthracite coal: They are the purest forms of coal

2di) 

--Zn not a transition metal, because it forms only Sc3+ ions with n d-electrons

Zinc doesn't show all the properties of transition elements cause 

1)it has complete D orbital 

2)it doesn't have variable oxidation states

2dii) 

 Fine chemicals are those chemicals manufactured in small quantities

 2diii)

AgBr

Mgcl2

Homogenous mixture is a mixture that is composed in equal amount of proportions .. eg CaCo3

Heterogenous is when it's unequal eg floodwater

Molar mass = 2×VD

 =2x68.75

=137.5g

Xcl3=137.5

X+3(35.5)=137.5

X+106.5=137.5

X=137.5-106.5

X=31g

The atomic mass of x is 31g

_____________________________

(3ai)

Petroleum Gas and Petrol>Kerosene>Diesel>Asphalt 

(3aii)

I.  Asphalt 

II. Kerosene

III. Petroleum Gas and petrol 

Iv. Asphalt 

(3bi)

I. Ethene

II. Propene 

(3bii)

(i) Structural Isomerism 

(ii) Stereo Isomerism 

(3biii)

19R - 1s² 2s² 2p6 3s² 3p6 4s¹

10S - 1s² 2s² 2p6

24T - 1s² 2s² 2p6 3s² 3p6 4s² 3d4

(3biv)

Group 6

(3ci)

I. AgNO3 and BaCl2

II. Bacl2 and Na2SO4

III. Ca(NO3)2 and H2CO3

(3cii)

(i) Filtration 

(ii) Flocculation

(iii) Disinfection

(3d)

Mass of NaCl

= mass of Nacl + mass of H2O

= (23 + 35.5) + 80g

= 58.5 + 80g = 138.5g

Hence 

Since 39.8g at 100°C = 35.9g at 15°C

138.5g at 100°C = Xg at 15°C

X = 138.5 × 35.9/39.8g

= 124.9g at 15°C

Hence mass of Nacl precipitated 

= 138.5 - 124.9g

= 13.6g of Nacl

___________________________

4b) le chatelier's principle states that for a reversible reaction in equilibrium, if any of the factors(temperature, concentration, pressure) keeping the system in equilibrium is altered, the system will shift to adjust the change

___________________

4bi) it will shift from left to right 

It will shift from left to right 

It will favor the forward reaction  by increasing the product

4iii)

Kc = [NH]2

   ----------

     {N2][H2]3

5a

i) increasing the surface area

  By adding catalyst to the reaction

5iii)

 If 100g of Caco3-----1mole of co2(22.4dm3)

4g------X

X=4*22.4/100

X=0.896dm^3

:.0.896dm^3 of CO2 was produced by 4g of Caco3

17.   Normal salt.... Na2co3

Acid salt... NaHSO4

Complex salt...Ca3[Co(Cl)6]2

KEEP REFRESHING..................
============================
ANSWERS LOADING...... STAY ONLINE

INVITE YOUR FRIENDS TO OUR WEBSITE