2004 年
化學 · 共 41 題 · 點擊選項即時核對答案
Which of the following combinations concerning the set-up shown below is correct after a current has flowed through the external circuit for some time ?
| Mass of anode | Colour intensity of the copper(II) sulphate solution | |
|---|---|---|
| increases | no change | |
| decreases | no change | |
| increases | decreases | |
| decreases | decreases |
What is the percentage by mass of nitrogen in the fertilizer (NH₄)₂HPO₄ ?
Ethane can be prepared by heating ethanol with excess concentrated sulphuric acid. The reaction involved can be represented by the equation: CH₃CH₂OH → CH₂=CH₂ + H₂O (conc. H₂SO₄) The type of reaction involved in the preparation is
Ethene can be prepared by heating ethanol with excess concentrated sulphuric acid. The reaction involved can be represented by the equation: CH₃CH₂OH → CH₂=CH₂ + H₂O (conc. H₂SO₄) Which of the set-ups shown below can be used to collect the ethene produced? (Relative atomic masses: H = 1.0, C = 12.0, N = 14.0, O = 16.0)
Refer to the melting points and boiling points of four substances at 1 atm pressure as listed in the table below:
| Substance | Melting point/°C | Boiling point/°C |
|---|---|---|
| argon | −189 | −186 |
| bromine | −7 | 59 |
| chlorine | −101 | −35 |
| sulphur dioxide | −75 | −10 |
Which substance exists as a liquid at −90°C and 1 atm pressure?
Refer to the melting points and boiling points of four substances at 1 atm pressure as listed in the table below:
| Substance | Melting point /°C | Boiling point /°C |
|---|---|---|
| argon | −189 | −186 |
| bromine | −7 | 59 |
| chlorine | −101 | −35 |
| sulphur dioxide | −75 | −10 |
Which of the following chemical bonds/attractive forces exist(s) in all four substances at 25°C and 1 atm pressure ?
The atomic number of element X is 15. It has only one isotope with a mass number of 31. Which of the following statements concerning X is correct ?
Which of the following substances can decolourise acidified potassium permanganate solution ?
Which of the following processes is/are involved in the production of whisky ?
Which of the following substances, when dissolved in water, gives a solution with pH greater than 7 ?