1999 年
化學 · 共 50 題 · 點擊選項即時核對答案
Which of the following diagrams can represent a mixture of two compounds ? (In these diagrams, ● and ○ represent a nitrogen atom and an oxygen atom respectively.)
One mole of calcium bromide contains
Which of the following substances has the lowest boiling point ?
Element X and element Y belong to the first three periods of the Periodic Table. The compound formed between these two elements has the following electronic structure :
(Only outermost shell electrons are shown.) How many electrons are there in the outermost shell of an atom of X and that of Y ?
| X | Y | |
|---|---|---|
| 1 | 3 | |
| 1 | 5 | |
| 2 | 8 | |
| 3 | 5 |
Consider the information concerning particle X and particle Y listed below :
| Particle | Number of protons | Number of electrons | Number of neutrons |
|---|---|---|---|
| X | 16 | 16 | 18 |
| Y | 16 | 18 | 18 |
Which of the following statements is correct ?
The concentration of an aqueous solution of an acid is 1.0 M. 25.0 cm³ of this acid solution requires 37.5 cm³ of 2.0 M sodium hydroxide solution for complete neutralization. What is the basicity of the acid ?
Substance X gives identical product(s) when treated with dilute sulphuric acid or concentrated sulphuric acid. X may be
Iron can be produced from iron(III) oxide by the following reaction : Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g) What mass of iron(III) oxide is required to produce 2.1 g of iron ? (Relative atomic masses : O = 16.0, Fe = 56.0)
In which of the following reactions is the underlined reactant reduced ?
Which of the following statements concerning bromine and chlorine is INCORRECT ?