IGCSE Chemistry: Specimen Questions with Answers 135 - 137 of 240

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Question 135

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Short Answer▾

Aluminum is used to make high voltage electricity cables

Details of Four Metals

The table shows some properties of four metals which could be used for overhead power cables.

Overhead Power Cables

Suggest why aluminum, rather than tungsten, is used in overhead power cables?

Explanation

Aluminum, rather than tungsten, is used in overhead power cable because has less melting point than tungsten.

Question 136

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Short Answer▾

Describe a test, other than measuring pH, which can be carried out on both acid solutions to confirm the explanation given in for the different pH values of the two acids.

Explanation

Question 137

Question

MCQ▾

Here are the steps given regarding purification of water for consumption:

Successive filters, Water plants, Settling tanks, Chlorination.

The correct order is:

Choices

Choice (4)

a.

b.

c.

d.

Answer

a.

Explanation

First, water from sea or river is brought through pipes to the water plants or water works. Second, this water is stored in “settling tanks” where most of the impurities settle down. Also potash alum is added to enhance sedimentation. Third, the water is made to pass through several filters. Last, the water is then chlorinated and passed for distribution. Chlorination kills majority of microorganisms like bacteria, etc.

Thus the correct order regarding purification of water for consumption is:

Water plants ⇾ Settling tanks ⇾ Successive filters ⇾ Chlorination

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