IGCSE Chemistry: Specimen Questions with Answers 103 - 106 of 240

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Question 103

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Short Answer▾

All metal nitrates decompose when heated. A few form a nitrite and oxygen. Most form the metal oxide, oxygen and a brown gas called nitrogen dioxide

Suggest why the nitrate of the metal, named in (a) (i) , decomposes less readily than lead (II) nitrate

[2 Marks]

Explanation

Because lead (II) nitrate is supports heating more than lithium nitrate.

Question 104

Question

MCQ▾

In the reaction between and , a pungent smelling gas is formed. Identify the gas.

Choices

Choice (4)

a.

b.

c.

d.

Answer

a.

Explanation

The reaction between and occurs as follows:

So we get , i.e.. ammonia as a gaseous product.

Now ammonia is a pungent smelling gas.

So the pungent smelling gas produced in the reaction between and is NH3.

Question 105

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Statement

True-False▾

Sulphuric acid is used to make fire extinguisher.

Answer

TRUE

Explanation

Sulphuric acid is used to make fire extinguisher.

In the soda-acid fire extinguisher, carbon dioxide is generated by mixing sulfuric acid with a solution of sodium bicarbonate.

So, the statement is true.

Question 106

Question

MCQ▾

Before the theory proposed by Newton, what was the idea regarding bonding of atoms?

Choices

Choice (4)

a.

2 atoms collide and form a bond

b.

Atoms have hooks to which they get attached and form a bond

c.

2 atoms overlap with each other to form a bond

d.

None of the above

Answer

b.

Explanation

Before the theory proposed by Newton, the idea regarding bonding of atoms was that the atoms have hooks to which they get attached and form a bond. The scientists in those days probably got influenced by the hand of the pirates where a hook was attached to one of their hands.

The Atoms Have Hooks

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