IGCSE Chemistry: Specimen Questions with Answers 91 - 94 of 240
Question number: 91
Question
Bases are ________ in nature.
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | rigid |
|
| b. | rough |
|
| c. | slippery |
|
| d. | elastic |
|
Answer
c.Explanation
Bases are ‘slippery’ in nature. When you rub soap in your hand, your hands turn slippery. This is because soaps comprises of bases.
Question number: 92
Write in Short
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Describe a test, other than measuring pH, which can be carried out on both acid solutions to confirm the explanation given in (b) (i) for the different pH values of the two acids.
Complete the following equations for reactions of these two acids.
Explanation
Question number: 93
Write in Short
carbon dioxide
Explanation
A compound made up of molecules containing one carbon atom and two oxygen atoms is an carbon di oxide. Carbon dioxide is normally found as a gas that is breathed out by animals and absorbed by green plants.
Question number: 94
Question
14 moles of oxygen atoms contain ________ atoms. Given:
[Give your answer correct to two decimal places]
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | 84.29 |
|
| b. | 84.27 |
|
| c. | 84.28 |
|
| d. | 84.26 |
|
Answer
c.Explanation
Avogadro number is the number of atoms or molecules present in one mole of a substance.
The value of Avogadro number is
Therefore the number of atoms present in 1 mole of oxygen atoms is
Thus, the number of atoms present in moles of oxygen atoms