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.

576.

The bonding pair of electrons in a Hydrogen Chloride molecule is pulled towards the chlorine atom because 

A.

chlorine has a larger atomic size

B.

chlorine has a larger atomic mass

C.

chlorine is more electronegative

D.

there is no bonding orbitals within the hydrogen atom

Correct answer is C

The chlorine atom is much more electronegative than the hydrogen atom, which makes this bond polar.

577.

What is the total number of shared pair of electrons in the compound above?

A.

5

B.

8

C.

10

D.

12

Correct answer is D

Each double bond has two pairs of valence electrons shared to form a covalent bonding. Also, every C-H bond, has 2 valence elctrons involved. Drawing the Lewis structure, you see that the above compound has 12 valence electrons shared.

578.

The atomic number of an isotope of hydrogen is equal to its mass number because it

A.

has a totally filled valence shell

B.

has a high charge to mass ratio

C.

does not contain neutrons

D.

exhibits isotopy

Correct answer is C

No explanation has been provided for this answer.

579.

Which of the following electron configurations represents the transition element Chromium \(_{24}Cr\)?

A.

\(1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{4}\)

B.

\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{6}\)

C.

\(1s^{2}2s^{2}2p^{6}3s^{2}3d^{4} 4s^{1}\)

D.

\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}\)

Correct answer is D

Electronic configuration of Chromium: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}\)

580.

Common Salt (NaCl) is used to preserve foods. Which of the following properties can be used to determine its purity before use?

A.

Solubility in water

B.

Melting point

C.

Relative density

D.

Crystalline nature

Correct answer is B

No explanation has been provided for this answer.