WAEC Chemistry Past Questions & Answers - Page 171

851.

Which of the following statements is true of the molecules of a gas under ideal conditions? The molecules

A.

move at random

B.

undergo inelastic collisions

C.

attract each other

D.

occupy a large volume

Correct answer is A

No explanation has been provided for this answer.

852.

Which of the following gases is light than air?

A.

CO2

B.

SO2

C.

HCI

D.

NH3

Correct answer is D

No explanation has been provided for this answer.

853.

When air is successively passed through sodium hydroxide solution, alkaline pyrogallol and then concentrated tetraoxosulphate (VI) acid, its remaining components are

A.

oxygen and water vapour

B.

oxygen and nitrogen

C.

carbon (IV) acid and noble gases

D.

nitrogen and noble gases

Correct answer is D

No explanation has been provided for this answer.

854.

What is the IUPAC name of the compound represented by the molecular formula NaCIO4?

A.

Sodium tetraoxochlorate (l)

B.

Sodium tetraoxochlorate (IV)

C.

Sodium tetraoxochlorate (VI)

D.

Sodium tetraoxochlorate(VII)

Correct answer is D

No explanation has been provided for this answer.

855.

How many atoms are there in one mole of hydrogen gas? [Avogadro's constant = 6.02 x 1023mol-1]

A.

1.2 x 10 23

B.

6.0 x 10 23

C.

1.2 x10 24

D.

6.0 x 10 24

Correct answer is C

One mole of hydrogen gas has 6.02 x 1023 molecules, and one molecule of hydrogen gas contains 2 atoms of hydrogen

therefore, one mole of hydrogen gas will contain 2 x 6.02 x10^23 atoms 

= 1.2 x 10^24 hydrogen atoms