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.

306.

Calcium chloride is an ionic compound. Which of the following statements account for its ionic character?

I. Calcium has high ionization energy.  II. Calcium has low ionization energy. III. Chlorine has high electron affinity. IV. Chlorine has high Ionization energy.

A.

I and Il only

B.

I, II and IV only

C.

II, IIl and IV only

D.

I, II, III and IV

Correct answer is C

- CaCl2 is an ionic compound owing to the large electronegative difference between the calcium atom and chlorine atom, which is greater than 2.0. In calcium chloride, the calcium atom donates its two electrons and become cation whereas each chlorine atom gain one electron, donated by Calcium, and get a negative charge.

- Ionization energies are always positive numbers, because energy must be supplied (an endothermic energy change) to separate electrons from atoms.

Chlorine has a high ionization energy

- Chlorine has high electron affinity among the elements. Its high affinity can be attributed to its large atomic radius, or size. Because chlorine's outermost orbital is 3p, its electrons have a large amount of space to share with an incoming electron.

307.

Dilution factor is the?

A.

amount of distilled water that is added to the concentrated solution to dilute it

B.

Quantity of distilled water added to l dm\(^3\) of the concentrated solution to give the dilute solution

C.

number of times the volume of the concentrated solution is diluted to give the dilute solution

D.

act of diluting the concentrated solution to obtain the dilute solution

Correct answer is C

- Dilution Factor is the factor by which the stock solution is diluted. It may be expressed as the ratio of the volume of the final diluted solution (V2) to the initial volume removed from the stock solution (V1)

- The dilution factor is the total number of unit volumes in which your material will be dissolved.

308.

which of the following quantities is a molar quantity?

A.

Molarity

B.

Molar mass

C.

Mass concentration

D.

Molality

Correct answer is C

No explanation has been provided for this answer.

309.

Which of the following processes is not exhibited by atoms in order to attain more stable electron configuration?

A.

Gaining of electrons

B.

Hybridization of orbitals

C.

Losing electrons

D.

Sharing electron

Correct answer is B

- An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration.

- Hybrid orbitals are useful in the explanation of molecular geometry and atomic bonding properties and are symmetrically disposed in space.

310.

The atomic number of an atom would be equal to its mass number if 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

- The mass number of an atom is its total number of protons and neutrons