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Chemistry Past Questions

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81 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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81 questions

Question 1 of 20 81 total questions

Question 21

jamb 1990

If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is?

A0.56 dm³

B5.60 dm³

C11.20 dm³

D22.40 dm³

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Question 22

jamb 1990

What volume of 11.0 M hydrochloric acid must be dilute to obtain 1 dm3 of 0.05 M acid?

A0.05 dm³

B0.10 dm³

C0.55 dm³

D11.0 dm³

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Question 23

jamb 1990

What is the concentration of H⁺ ions in moles per dm³ of a sodium of pH 4.398?

A4.0 χ 10^-5

B0.4 χ 10^-5

C4.0 χ 10^-3

D0.4 χ 10^-3

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Question 24

jamb 1990

2.0g of a monobasic acid was made up to 250 cm³ with distilled water. 25.00 cm³ of this solution required 20.00cm³ of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is?

A200 g

B160 g

C100 g

D50 g

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Question 25

jamb 1990

Na2C2O4 + CaCl2 → CaC2O4 + 2NaCl. Given a solution of 1.9g of sodium oxalate in 50g of water at room temperature, calculate the minimum volume of 0.1 M calcium oxalate using the above equation?

A1.40 χ 10² dm³

B14.0 χ 10² cm³

C1.40 χ 10^-2 dm^-2

D14.0 χ 10^-2 cm³

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Question 26

jamb 1990

Smoke consist of?

Asolid particles dispersed in liquid

Bsolid or liquid particles dispersed in gas

Cgas or liquid particles dispersed inliquid

Dliquid particles dispersed inliquid

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Question 27

jamb 1990

The solubility in moles per dm³ of 20g of CuSO₄ dissolve in 100 of water at 180°C is?

(Cu = 63.5, S = 32, O = 16)

A0.13

B0.25

C1.25

D2.00

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Question 28

jamb 1990

A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?

Ais deliquescent

Bis hygroscopic

Chas some molecules of water of crystallization

Dis efflorescent

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Question 29

jamb 1990

10.0 dm³ of air containing H₂S as an impurity was passed through a solution of Pb(NO₃)₂ until all the H₂S had reacted. The precipitate of PbS was found to weigh 5.02 g. According to the equation:

Pb(NO₃)₂ + H₂S → PbS + 2HNO₃ the percentage by volume of hydrogen sulphide in the air is?

(Pb = 207, S = 32, GMV at s.t.p = 22.4dm³)

A50.2

B47.0

C4.70

D0.47

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Question 30

jamb 1990

Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.
The relative abundance of the isotope of mass number 37 is?

A20

B25

C50

D75

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Question 31

jamb 1990

X(g) → X\(^-\)(g). The type of energy involved in the above transformation is?

Aionization energy

Bsublimation energy

Clattice energy

Delectron affinity

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Question 32

jamb 1990

Which of the following terms indicates the number of bonds that can be formed by an atom?

AOxidation number

BValence

CAtomic number

DElectronegativity

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Question 33

jamb 1990

.....................P....Q.....R......S
Proton..............13....16....17.....19
Electron............13....16....17.....19
Neutron.............14....16....35.....20

Which of the four atoms P,q,R and in S in the above data can be described by the following properties relative atomic mass is greater than 30 but less than 40; it has an odd atomic number and forms a unipositive ion in solution?

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Question 34

jamb 1990

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that?

Acollisions are perfectly elastic

Bforces of repulsion exist

Cforces of repulsion are in equilibrium

Dcollision are inelastic

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Question 35

jamb 1990

Equal volumes of CO,SO2, NO2 and H2S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?
(S = 32, C = 12, O = 16, N = 14, H = 1)

ACO, SO₂,NO₂,H₂S

BSO₂,NO₂,H₂S,CO

CCO,H₂S,SO₂,NO₂

DCO,H₂S,NO₂,SO₂

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Question 36

jamb 1990

The volume occupies by 1.58g of a gas at s.t.p is 500cm³. What is the relative molecular mass of the gas?

(G.M.V at s.t.p = 22.40dm³)

A28

B32

C44

D71

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Question 37

jamb 1990

If a gas occupies a container of volume 146 cm3 at 18°C and 0.971 atm, its volume in cm3 at s.t.p is?

A133

B146

C266

D292

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Question 38

jamb 1990

Which of the following is formed when maltose reacts with concentrated tetraoxosulphate (VI) acid ?

ACarbon (IV) oxide

BCoal tar

CCharcoal

DToxic fumes

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Question 39

jamb 1990

The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ?

A45

B55

C80

D100

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Question 40

jamb 1990

Alkaonic acids have low volatility compared with alkanols because they?

Aare more polar than alkaonls

Bhave two oxygen atoms while alkanols have one

Cform hydrogen bonds while alkanols do not

Dform two hydrogen bonds while alkanols form one

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