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化學 · 共 135 題 · 點擊選項即時核對答案
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| Both dry ice and quartz exist in the form of discrete molecules. | Carbon and silicon atoms have the same number of electrons in their outermost shells. |
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| When a piece of iron wire coupled with a piece of tin wire is left in the air for a long period of time, the iron wire does not corrode. | Tin prevents iron from corrosion by sacrificial protection. |
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| The basicity of ethanoic acid is four. | One molecule of ethanoic acid contains four atoms of hydrogen. |
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| Nylon softens on heating. | Nylon is a condensation polymer. |
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| Huge quantities of carbon dioxide produced by the burning of fossil fuels cause the greenhouse effect. | Carbon dioxide can trap the solar energy which is re-radiated from the earth’s surface to the atmosphere. |
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| If a student accidentally spills some hydrochloric acid on his hand, he should immediately wash his hand with sodium hydroxide solution. | Sodium hydroxide solution can neutralise hydrochloric acid. |
For Questions 45–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| Panadol is an antacid. | Panadol contains acetylsalicylate as the active ingredient. |
For each of the following questions, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| Hydrogen chloride has a lower melting point than sodium chloride. | In each molecule of hydrogen chloride, a hydrogen and a chlorine atom are joined together by a covalent bond. |
For each of the following questions, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| At room temperature and pressure, the molar volume of oxygen gas is greater than that of hydrogen gas. | The relative atomic mass of oxygen is greater than that of hydrogen. |
For each of the following questions, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.
| 1st statement | 2nd statement |
|---|---|
| Iron reacts with chlorine to form iron(II) chloride. | Iron is a reducing agent in this reaction. |