WAEC Past Questions and Answers - Page 1756

8,776.

Which of the following electronic structures belongs to a noble gas?

A.

1s22s2

B.

1s 22s22p4

C.

1s22s22p63s23p6

D.

1s22s22p2

E.

1s22s22p 63s23p3

Correct answer is C

\(1s^22s^22p^63s^23p^6\)

Which is Argon = 2,8,8

8,777.

The positive of an element in the Periodic Table is determined by

A.

its density

B.

its atomic radius

C.

its relative atomic mass

D.

the number of protons in its atom

E.

the number of neutrons in its atom

Correct answer is D

No explanation has been provided for this answer.

8,778.

Mg\(_2\) + 2HCI\(_{(aq)}\) → MgCI\(_{2(g)}\) + H\(_{2(g)}\).

From the equation above what mass of hydrogen would be produced if 12.0 g of magnesium reacted completely with dilute hydrochloric acid? (H = 1, Mg = 24)

A.

1.0g

B.

2.0g

C.

6.0g

D.

12.0g

E.

24.0g

Correct answer is A

Mg\(_2\) + 2HCI\(_{(aq)}\) → MgCI\(_{2(g)}\) + H\(_{2(g)}\).

24g Mg reacts with 2g H

1g Mg = \(\frac{2}{24}\)g H

12g Mg = \(\frac{2}{24} \times 12\)g H

= 1g H.

8,779.

When water is dropped on calcium carbide, the gaseous product is an

A.

alkane

B.

alkene

C.

alkyne

D.

alkanol

E.

alkanal

Correct answer is C

No explanation has been provided for this answer.

8,780.

How many faradays of electricity are required to liberate 9g aluminium? (AI = 27)

A.

0.1

B.

0.3

C.

1.0

D.

2.7

E.

3.0

Correct answer is C

No explanation has been provided for this answer.