IGCSE Chemistry: Specimen Questions with Answers 126 - 128 of 240
Question number: 126
Question
Which of the following is Not a good absorber of sound?
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | Curtains |
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| b. | Wooden doors |
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| c. | Metal Cupboards |
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| d. | Cushions |
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Answer
c.Explanation
Correct option is C because Soundproofing is any means of reducing the sound pressure with respect to a specified sound source and receptor.
There are several basic approaches to reducing sound: increasing the distance between source and receiver, using noise barriers to reflect or absorb the energy of the sound waves, using damping structures such as sound baffles, or using active antinoise sound generators. And metal cupboard comes under category of sound proofing.
Question number: 127
Question
Lanthanides and actinides are ________ in nature.
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | Non metallic |
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| b. | Metallic |
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| c. | None of the above |
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| d. | Question does not provide sufficient data or is vague |
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Answer
b.Explanation
Lanthanides and Actinides are metallic in nature.
Question number: 128
Question
1 mole of any gaseous substance occupies ________ litres at S. T. P.
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | 22.4 |
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| b. |
|
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| c. | Question does not provide sufficient data or is vague |
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| d. | All of the above |
|
Answer
a.Explanation
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Molar volume of a gas is the volume occupied by 1 mole of gas at the standard temperature and pressure (S. T. P. ). One mole of a gas occupies litres or at S. T. P.
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S. T. P means standard temperature and pressure. At S. T. P. , the value of temperature is or and that of pressure is of Hg or .
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Thus one mole of any substance occupies litres at standard temperature and pressure.