1.简单
原子中哪种粒子带正电荷?
- A质子
- B电子
- C中子
- D光子
2.简单
How many electrons are shared in a double covalent bond?
- A8
- B2
- C4
- D6
3.简单
元素的原子序数告诉你什么?
- A1 摩尔该元素中的原子数
- B每个原子中的中子数
- C原子核中质子和中子的总数
- D每个原子中的质子数
4.中等
Potassium forms K⁺ ions and sulfur forms S²⁻ ions. What is the name and formula of their compound?
- APotassium sulfide, KS₂
- BPotassium sulfate, K₂SO₄
- CPotassium sulfide, K₂S
- DPotassium sulfite, KS
5.中等
88 g 二氧化碳(摩尔质量 44 g/mol)是多少摩尔?
- A2 mol
- B3872 mol
- C44 mol
- D0.5 mol
6.中等
A radioactive isotope has a half-life of 5 days. A sample starts with 80 g. How much is left after 10 days?
- A10 g
- B40 g
- C0 g
- D20 g
7.困难
Why are the radioactive tracers used for medical imaging usually chosen to have short half-lives?
- AThey emit only alpha particles, which are harmless inside the body
- BThey give a strong signal for imaging but leave the body's tissues exposed only briefly
- CThey stay active for many years, so a single dose can be used for every future scan
- DShort half-life isotopes are not radioactive
8.困难
在反应 CuO + H₂ → Cu + H₂O 中,哪种物质被还原?
- A铜,因为它失去电子
- B水,因为它是生成的
- C氧化铜,因为铜得到电子
- D氢,因为它得到氧
答案
- 1. A · 质子
- 2. C · 4
- 3. D · 每个原子中的质子数
- 4. C · Potassium sulfide, K₂S
- 5. A · 2 mol
- 6. D · 20 g
- 7. B · They give a strong signal for imaging but leave the body's tissues exposed only briefly
- 8. C · 氧化铜,因为铜得到电子
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