1990 年
化學 · 共 34 題 · 點擊選項即時核對答案
Which of the following elements in the third period of the Periodic Table is the strongest reducing agent ?
A cation of a certain element has 22 electrons and a mass number of 55. If the charge on the cation is +3, the number of neutrons in the cation is
The atomic numbers of element X and element Y are 13 and 16 respectively. The formula of the compound formed between X and Y is likely to be
Which of the following combinations concerning the isotopes of an element is correct ?
| No. of protons | No. of neutrons | No. of electrons | |
|---|---|---|---|
| same | different | same | |
| same | same | different | |
| different | same | different | |
| same | different | different |
In going down the group VI elements of the Periodic Table, there is an increase in
Which of the following combinations is correct ?
The boiling points of some hydrocarbons are given in the table below:
| Hydrocarbon | Ethane | Ethene | Propene |
|---|---|---|---|
| Boiling point / °C | −89 | −104 | −48 |
If a mixture of these three hydrocarbons at −110°C is allowed to warm up gradually to −80°C, which of the following will happen?
The reaction between lead(II) nitrate solution and sodium hydrogencarbonate solution can be represented by the equation below : Pb²⁺(aq) + 2HCO₃⁻(aq) → PbCO₃(x) + H₂O(y) + CO₂(z)
| x | y | z | |
|---|---|---|---|
| aq | aq | aq | |
| aq | l | g | |
| s | aq | g | |
| s | l | g |
Which of the following contains the largest number of ATOMS at room temperature and pressure? (Relative atomic masses: H = 1.0, N = 14.0, Cl = 35.5; Molar volume of gas at room temperature and pressure = 24 dm³)
The molecular formula of a gas is X₃. If the Avogadro's Number is L mol⁻¹, how many molecules are there in 96 g of X₃ ? (Relative atomic mass of X = 16.0)
If 2 g of carbon dioxide gas contain x molecules, how many molecules are present in 2 g of helium gas ? (Relative atomic masses: He = 4.0, C = 12.0, O = 16.0)