Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

2,956.

What volume of oxygen measured at s.t.p would be liberated on electrolysis by 9650 coulombs of electricity?

(Molar volume of gas = 22.4 dm\(^3\), F = 96,500 C mol-)

A.

22.4 dm3

B.

11.2 dm3

C.

1.12 dm3

D.

0.560 dm3

Correct answer is D

For a diatomic divalent element like oxygen:

4 faraday (4 *  96,500) = 1 mole of the element  = Molar volume of gas = 22.4

: 4 *  96,500 = 22.4

  9650 = x 

: x = \(\frac{9650 * 22.4}{ 4 *  96,500}\)

x = 0.56dm\(^3\)

 

2,958.

Which of the following compounds is a base?

A.

CO2

B.

CaO

C.

H3PO3

D.

CH3COOCH3

Correct answer is B

No explanation has been provided for this answer.

2,959.

A few drops of concentrated HCI are added to about 10cm3 of a solution of pH 3.4. The pH of the resulting mixtures is?

A.

less than 3.4

B.

greater than 3.4

C.

unaltered

D.

the same as that of pure water

Correct answer is A

The addition of concentrated HCl to the solution makes the solution more acidic and the pH falls below the original value that is the pH value of the solution will now be less than 3.4.

2,960.

Which of the following atoms represents deuterium?

A.

No protons = 1, No of neutrons = 0, No of electrons = 0

B.

No protons = 1, No of neutrons = 0, No of electrons = 1

C.

No protons = 1, No of neutrons = 1, No of electrons = 1

D.

No protons = 1, No of neutrons = 2, No of electrons = 1

Correct answer is C

No explanation has been provided for this answer.