CIE Chemistry (US-0439): Specimen Questions with Answers 148 - 150 of 240

Question number: 148

True-False▾

Is the Following Statement True or False?

According to “Gay-Lussac’s Law of Combining Volumes”, the volume of solids and liquids are assumed to be zero in a chemical reaction.

Answer

TRUE

Explanation

The volume of solids and liquid does not change remarkably on slight change in temperature but volume of gases change tremendously. “Gay- Lussac’s Law of Combining Volumes” deals with volumes. Since there is no remarkable change in volume of solids and liquids, hence according to “Gay-Lussac’s Law of Combining Volumes”, the volume of solids and liquids are assumed to be zero in a chemical reaction.

Thus the given statement is true.

Question number: 149

MCQ▾

Question

Which statement about the substances used is correct?

Choices

Choice (4) Response

a.

The coating is plastic because it conducts electricity well

b.

The core is copper because it conducts electricity well

c.

The core is copper because it is cheap and strong

d.

The core is iron because it is cheap and strong

Answer

b.

Explanation

Correct Option is B i. e. The core is copper because it conducts electricity well. Because in this metal electron move freely inside it and in this metal resistance is also less as compared to other metals.

Question number: 150

MCQ▾

Question

Elements in the same group have the same valency.

Choices

Choice (4) Response

a.

False

b.

True

c.

Sometimes false

d.

Sometimes true

Answer

b.

Explanation

Correct option is true because this is the law of general chemistry is that Elements in the same group have the same valency.

Therefore, elements whose atoms can have the same number of valence electrons are grouped together in the periodic table of the elements. As a general rule, a main group element (except hydrogen or helium) tends to react to form a closed shell, corresponding to the electron configuration s2p6.

Image of valence electrons

Image of Valence Electrons

Image of valence electrons