IGCSE Chemistry Paper-1: Specimen Questions with Answers 74 - 76 of 99

Passage

In the below questions. Complete the following puzzle.

Complete the Puzzle Above

Question 74 (5 of 6 Based on Passage)

Question

MCQ▾

TOP TO DOWN: At position 50, a gas with many industrial applications, important for plant growth. Belongs to group VA

Choices

Choice (4)

a.

Carbon

b.

Phosphorous

c.

Oxygen

d.

Nitrogen

Answer

d.

Explanation

Nitrogen is important to the chemical industry. It is used to make fertilizers, nitric acid, nylon, dyes and explosives. A colorless, odorless gas. Its electronic configuration is 1s2 2s2 2p3

Hence period = 2 + 3 = 5A

Completed Puzle Given in the Question

Question 75 (6 of 6 Based on Passage)

Question

MCQ▾

ACROSS: At position 46, an element with atomic number 6.

Choices

Choice (4)

a.

Nitrogen

b.

Neon

c.

Silicon

d.

Oxygen

Answer

d.

Explanation

Carbon is a chemical element with symbol and atomic number . On the Periodic table, it is the first (row 2) of six elements in column (group) 14, which have in common the composition of their outer electron shell. It is nonmetallic and tetravalent — making four electrons available to form covalent chemical bonds.

Completed Puzle Given in the Question

Question 76

Question

MCQ▾

What is the Chemical formula and chemical name of vinegar?

Choices

Choice (4)

a.

Carbonic acid - H2 CO3

b.

Acetic acid - CH3COOH

c.

Lactic acid - CH3CH (OH) COOH

d.

Nitric Acid - HNO3

Answer

b.

Explanation

Acetic acid has a chemical formula CH3COOH . Vinegar is roughly 3 – 9 % acetic acid by volume, making acetic acid the main component of vinegar apart from water. Vinegar is now mainly used as a cooking ingredient. Historically, as the most easily available mild acid, it had a great variety of industrial, medical and domestic uses, some of which (such as its use as a general household cleanser) are still promoted today.

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