护理入学考试化学练习卷（附答案）

What is an electrolyte?

1. AA substance that dissolves as whole molecules without forming any ions
2. BA metal that conducts electricity as a solid
3. CA gas that dissolves in blood
4. DA substance that forms ions and conducts electricity when dissolved in water

催化剂有什么作用？

1. A减慢反应并被消耗
2. B改变反应的产物
3. C加快反应而自身不被消耗
4. D提供反应的反应物

Which element exists naturally as diatomic molecules (two atoms joined together)?

1. ASodium
2. BHelium
3. COxygen
4. DIron

哪组系数能配平方程式 __H₂ + __O₂ → __H₂O？

1. A1, 2, 1
2. B1, 1, 1
3. C2, 1, 2
4. D2, 2, 2

Which nuclear process powers the Sun?

1. ACombustion of hydrogen gas with oxygen in its core
2. BFusion of hydrogen nuclei to form helium
3. CAlpha decay of helium
4. DFission of uranium into smaller nuclei

A reaction is at equilibrium. More of one reactant is added. According to Le Chatelier's principle, what happens?

1. AThe equilibrium shifts toward the reactants
2. BThe reaction stops completely
3. CNothing changes
4. DThe equilibrium shifts toward the products

Why are the radioactive tracers used for medical imaging usually chosen to have short half-lives?

1. AShort half-life isotopes are not radioactive
2. BThey give a strong signal for imaging but leave the body's tissues exposed only briefly
3. CThey stay active for many years, so a single dose can be used for every future scan
4. DThey emit only alpha particles, which are harmless inside the body

Ethene has the structure H₂C=CH₂. How many electrons are shared between the two carbon atoms?

1. A2
2. B8
3. C4
4. D6