2004 年

How many elements does ammonium dichromate consist of ?

X, Y and Z are three consecutive elements in the Periodic Table. X forms a stable anion X⁻, while Z forms a stable cation Z⁺. Which of the following statements about X, Y and Z is correct ?

The relative atomic masses of hydrogen and oxygen are 1.0 and 16.0 respectively. Which of the following statements concerning 36.0 g of water is correct? (Molar volume of gas at room temperature and pressure = 24 dm³; Avogadro constant = 6.02 × 10²³ mol⁻¹)

Which of the following substances is the poorest electrical conductor ?

Decomposition of KClO₃(s) at elevated temperatures gives KCl(s) and O₂(g) as the only products. What is the volume of O₂(g) produced, measured at room temperature and pressure, when 63.1 g of KClO₃(s) undergoes complete decomposition? (Relative atomic masses: O = 16.0, Cl = 35.5, K = 39.1; molar volume of gas at room temperature and pressure = 24 dm³)

In which of the following compounds does sulphur exhibit the lowest oxidation number ?

Which of the following pairs of ions would react together to form a white precipitate?

Which of the following combinations concerning the properties of gases is INCORRECT ?

The relative atomic mass of element X is 74.9. It forms an oxide containing 24.3% of oxygen by mass. What is the mole ratio of X to oxygen in the oxide ?