护理入学考试化学练习卷（附答案）

氯、溴和碘是哪一族的例子？

1. A稀有气体
2. B碱金属
3. C过渡金属
4. D卤素

Which state of matter has a fixed volume but takes the shape of its container?

1. ALiquid
2. BSolid
3. CGas
4. DPlasma

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

1. AIron
2. BOxygen
3. CSodium
4. DHelium

When a nucleus emits a beta particle, how do its mass number and atomic number change?

1. AMass number falls by 4 and atomic number falls by 2
2. BMass number rises by 1 and atomic number stays the same
3. CBoth fall by 1
4. DMass number stays the same and atomic number rises by 1

At 20 °C, about 36 g of NaCl dissolves in 100 g of water. If 50 g of NaCl is stirred into 100 g of water at 20 °C, what happens?

1. ANone of the salt dissolves
2. BAll 50 g dissolves
3. CAbout 36 g dissolves and about 14 g stays undissolved
4. DAbout 14 g dissolves and about 36 g stays undissolved

To which family of organic compounds does ethanol, C₂H₅OH, belong?

1. AAlcohols
2. BCarboxylic acids
3. CAlkanes
4. DEsters

A solution contains 250 mg of a substance in every 5 mL. How many grams of the substance are in 100 mL?

1. A50 g
2. B5 g
3. C0.5 g
4. D5000 g

Raising the temperature by 10 °C can roughly double the rate of many reactions. What is the main reason?

1. AMany more collisions have at least the activation energy
2. BThe particles become larger and easier to hit
3. CThe reaction becomes more exothermic
4. DThe activation energy itself is lowered by the extra heat