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Chemistry Past Questions

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77 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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77 questions

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Question 11

waec 2006

Considered the reaction: H⁺_(aq) + OH ^- _(aq) → H₂O
_(l). The energy change taking place in the reaction above is enthalpy of

Aformation

Bhydration

Cneutralization

Dsolution

View Explanation & Discuss

Question 12

waec 2006

Consider the reaction represented by the equation. 2NaHCO_3(s) \(\rightarrow\) 2Na₂CO _3(S) + CO _2(g) + H₂O_(g) what volume of carbon (IV)oxide at s.t.p is evolved when 0. 5 moles of NaHCO₃ is heated? [Molar volume = 22.4 dm³ at s.t. p]

A1.12dm³

B2.24dm³

C5.6dm³

D56.0dm³

View Explanation & Discuss

Question 13

waec 2006

If 20 cm3 of distilled water is added to 80cm 3 of 0. 50 mol dm-3 hydrochloric acid, the new concentration of the acid will be

A0.10mol dm^-3

B0.20mol dm^-3

C0.40mol dm^-3

D2.00mol dm^-3

View Explanation & Discuss

Question 14

waec 2006

If 1 mole of sodium contains 6 x 10²³ atoms, how many atoms are contained in 0.6 g of sodium? [Na = 23]

A1.56 x 10²³

B1.56 x 10²²

C3.6 x 10²³

D3.6 x 10²²

View Explanation & Discuss

Question 15

waec 2006

An atom ²³⁸₉₂X decays by alpha particle emission to give an atom Y. The atomic number and mass number of Y are

A90 and 234 respectively

B91 and 238 respectively

C92 and 236 respectively

D93 and 238 respectively

View Explanation & Discuss

Question 16

waec 2006

An element X has isotopic masses of 6 and 7. if the relative abundance is 1 to 12.5 respectively, what is the relative atomic mass of X?

A6.0

B6.1

C6.9

D7.0

View Explanation & Discuss

Question 17

waec 2006

How many orbitals are in the d-sub shell?

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Question 18

jamb 2006

In the diagram above, the respective activation energies for the catalyzed and uncatalyzed reactions in kJ are

A45 and 50

B50 and 45

C30 and 35

D40 and 45

View Explanation & Discuss

Question 19

jamb 2006

Which of the following functional groups will give gas bubbles when treated with a saturated solution of sodium hydrogen trioxocarbonate (IV)?

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Question 20

jamb 2006

2-methylbut-2-ene has the structure

View Explanation & Discuss

Question 21

jamb 2006

The oxidation of the compound above produces

A2-butanone

B2-butanal

C3-butanal

D3-butanone

View Explanation & Discuss

Question 22

jamb 2006

In the diagram above, mixture Y is

ANH₄NO_3(s) + CaSO_4(s),/sub>

BNH₄Cl_(s) + NaNO_2(s)

CNH₄NO_2(s) + Na₂SO_4(s)

DNH₄Cl_(s) + Ca(OH)_2(s)

View Explanation & Discuss

Question 23

jamb 2006

In the diagram above, gas X is

Ahydrogen

Bchlorine

Coxygen

Dhydrogen chloride

View Explanation & Discuss

Question 24

jamb 2006

5SO\(_2\)(g) + 2KMnO\(_4\)(aq) + 2H\(_2\)O(l) → K\(_2\)SO\(_4\) + 2MnSO\(_4\)(aq) + 2H\(_2\)SO\(_4\)(aq)
In the reaction above, the products give a

Apurple solution

Bpurple precipitate

Ccolourless precipitate

Dcolourless solution

View Explanation & Discuss

Question 25

jamb 2006

If the heat of combustion of hydrogen is -285.8kJ,
What is the heat of formation of water?

A+571.6 kJ

B-571.6 kJ

C-285.8 kJ

D+285.8 kJ

View Explanation & Discuss

Question 26

jamb 2006

Na\(_2\)CO\(_3\)(g) + 2HCl(aq) → 2NaCl(aq) + H\(_2\)O(l) + CO\(_2\)(g)
How many moles of sodium trioxocarbonate (IV) are there in a 25 cm\(^3\) solution which required 10cm\(^3\) of 0.05 mol dm\(^3\) hydrochloric acid solution to neutralize it?

A1.000 mole

B0.100 mole

C0.010 mole`

D0.111 mole

View Explanation & Discuss

Question 27

jamb 2006

In the electrolysis of CuSO\(_4\)(g) using platinum electrodes, the reaction at the anode is

A4H⁺ + 4e^- → 2H₂

B4OH^- + 4e^- → 2H₂O + O₂

C2OH - 2e^- → 2OH

D2OH^- + 2OH^- → 2H₂O + O₂

View Explanation & Discuss

Question 28

jamb 2006

In which of the following is the oxidation number of sulphur equal to - 2?

ASO₃

BS₈

CH₂S

DSO₂

View Explanation & Discuss

Question 29

jamb 2006

The solution that will conduct the highest amount of electricity is?

A0.5 mol dm^-3 of hydrochloric acid

B2.0 mol dm^-3 of hydrochloric acid

C0.5 mol dm^-3 ethanoic acid

D2.0 mol dm^-3 ethanoic acid

View Explanation & Discuss

Question 30

jamb 2006

Zinc and carbon rods are used as anode and cathode respectively in a

ALeclanche cell

Blead accumulator

CDaniel cell

Dvoltaic cell

View Explanation & Discuss

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