1.简单
What does organic chemistry study?
- ACompounds based on carbon
- BOnly the noble gases
- CCompounds made of metals
- DOnly compounds found in plants
2.简单
What is gamma radiation?
- AA slow-moving electron
- BHigh-energy electromagnetic radiation with no mass or charge
- CA fast stream of protons from the nucleus
- DA stream of helium nuclei with a positive charge
3.简单
一个中性原子有 11 个质子。它有多少个电子?
- A10
- B11
- C12
- D22
4.中等
Which nuclear process powers the Sun?
- AAlpha decay of helium
- BFission of uranium into smaller nuclei
- CCombustion of hydrogen gas with oxygen in its core
- DFusion of hydrogen nuclei to form helium
5.中等
A reaction is at equilibrium. More of one reactant is added. According to Le Chatelier's principle, what happens?
- AThe reaction stops completely
- BThe equilibrium shifts toward the reactants
- CNothing changes
- DThe equilibrium shifts toward the products
6.中等
A solution has a pH of 10. What is its pOH at 25 °C?
- A14
- B24
- C10
- D4
7.困难
Which compound contains both ionic and covalent bonds?
- AMethane, CH₄
- BWater, H₂O
- CSodium sulfate, Na₂SO₄
- DSodium chloride, NaCl
8.困难
2090 J of heat is added to 50 g of water (specific heat 4.18 J/g·°C). By how much does its temperature rise?
- A5 °C
- B10 °C
- C41.8 °C
- D20 °C
答案
- 1. A · Compounds based on carbon
- 2. B · High-energy electromagnetic radiation with no mass or charge
- 3. B · 11
- 4. D · Fusion of hydrogen nuclei to form helium
- 5. D · The equilibrium shifts toward the products
- 6. D · 4
- 7. C · Sodium sulfate, Na₂SO₄
- 8. B · 10 °C
完整分步解答:请在 examproblems.com 上练习本主题。