IGCSE Chemistry: Specimen Questions with Answers 120 - 123 of 240

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Question 120

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Short Answer▾

Impure water needs to be treated if it is to be used in the home.

Describe a chemical test for water.

test …

result …

Explanation

TEST Water can also be detected using blue anhydrous cobalt chloride.

RESULT

Question 121

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Short Answer▾

The structures of five atoms, A, B, C, D, and E, are shown below.

Structures of Five Atoms

Which structure has two neutrons in its nucleus? …

Explanation

Correct option is B because option B represent Helium (He) gas and helium gas has no. of electron is , no. of proton is and no. of neutron is .

Question 122

Question

MCQ▾

The first metal used by early man in “Chalcolithic period” was ________.

Choices

Choice (4)

a.

Silver

b.

Copper

c.

Iron

d.

Golden

Answer

b.

Explanation

  • Chalcolithic came from the Greek word “chalcos” which means “copper” and “lithos” which means “stone” .
  • The first metal used by the early man in “Chalcolithic period” was copper.

Question 123

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Short Answer▾

Substances can be classified as:

Elements can be divided into:

Define each of the following terms:element

Explanation

each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e.. the number of protons in the nuclei of its atoms.

Developed by: