2003 年
化學 · 共 33 題 · 點擊選項即時核對答案
Gallium (Ga) occurs naturally in two isotopic forms, ⁶⁹Ga and ⁷¹Ga. The table below lists the relative abundance of each isotope.
| Isotope | Relative abundance |
|---|---|
| ⁶⁹Ga | 60.2% |
| ⁷¹Ga | 39.8% |
What is the relative atomic mass of gallium ?
Which of the following substances will NOT react with bromine water ?
In the electrolysis of a copper(II) sulphate solution, copper is used as the anode and carbon as the cathode. Which of the following statements concerning this electrolysis is correct ?
Which of the following conversions is NOT a reduction ?
An organic compound has the following structure:
The systematic name of this compound is
Consider the following information about three elements, X, Y and Z.
| Element | Atomic number |
|---|---|
| X | 12 |
| Y | 16 |
| Z | 17 |
Which of the following statements concerning X, Y and Z is correct ?
Soap was prepared by heating fat with sodium hydroxide solution for some time. Concentrated sodium chloride solution was then added to the resulting mixture. The purpose of adding concentrated sodium chloride solution is
A sample of zinc granules of mass 1.8 g was added to 100 cm³ of 0.25 M hydrochloric acid. What is the theoretical volume of hydrogen produced at room temperature and pressure? (Relative atomic mass: Zn = 65.4; molar volume of gas at room temperature and pressure = 24 dm³)
Consider the following equation: 5H₂S + 2KMnO₄(aq) + 3H₂SO₄(aq) → 5S(x) + 8H₂O(y) + 2MnSO₄(z) + K₂SO₄(aq) Which of the following combinations is correct ?
| x | y | z | |
|---|---|---|---|
| s | aq | aq | |
| s | l | aq | |
| aq | aq | s | |
| aq | l | s |
An atom of element X has 20 protons while an atom of element Y has 7 electrons. What is the formula of the compound formed from X and Y ?