CIE Chemistry (US-0439): Specimen Questions with Answers 116 - 118 of 240

Question number: 116

Short Answer Question▾

Write in Short

Explain why iodine does not react with potassium bromide. [Total: 10 Marks]

Explanation

Iodine does not react with potassium bromide because the less reactive element is removed from the compound and replaced by the more reactive element. For example, if iodine is added to a solution of potassium bromide, then there is no reaction.

Question number: 117

MCQ▾

Question

According to “Vitalism theory”:

Choices

Choice (4) Response

a.

Vital force is responsible for the preparation of inorganic substances.

b.

Vitamins are inorganic substances.

c.

Vital force is responsible for the preparation of organic substances.

d.

Vitamins are organic substances.

Answer

c.

Explanation

  • According to “Vitalism theory”, the organic substances in nature are directly derived from the nature. They cannot be prepared artificially. There is some natural force which prepares these organic substances. This force was known as vital force.

  • Thus according to “Vitalism theory”, vital force is responsible for the preparation of organic substances. Organic substances such as urea, methane, chloroform, etc. cannot be prepared in the laboratory. Today this theory is invalid because thousands of organic compounds are being prepared in the laboratory.

Question number: 118

Short Answer Question▾

Write in Short

Complete the following sentences about isotopes using words from the list below

sentences about isotopes using words

Sentences About Isotopes Using Words

sentences about isotopes using words

Isotopes are atoms of the same element with the same number of…………………. .

And different numbers of…………………… Some isotopes such as uranium-235 are

……………………. Uranium can be used as a source of…………………… [4 Marks]

Explanation

Isotopes are the atoms of same element with the same no. of proton and different no. of neutrons. Some isotopes such as are radioactive. can be used as a source of energy. Because The Uranium Atom. … The isotope is important because under certain conditions it can readily be split, yielding a lot of energy. It is therefore said to be ‘fissile’ and we use the expression ‘nuclear fission’. Meanwhile, like all radioactive isotopes, they decay. As shown in figure given below.

The isotopes of hydrogen

The Isotopes of Hydrogen

The isotopes of hydrogen

The use of Uranium as nuclear fuel

The use of Uranium as nuclear fuel

The Use of Uranium as Nuclear Fuel

The use of Uranium as nuclear fuel