护理入学考试化学练习卷（附答案）

Charles's law describes the relationship between which two properties of a gas, at constant pressure?

1. APressure and number of moles
2. BPressure and volume
3. CDensity and mass
4. DVolume and temperature

钠的化学符号是什么？

1. ANa
2. BS
3. CSo
4. DN

What is a cation?

1. AA positively charged ion
2. BA molecule with no charge
3. CA neutral atom
4. DA negatively charged ion

A student tests how temperature affects the rate of a reaction. What is the independent variable?

1. AThe temperature
2. BThe volume of acid, which is kept the same
3. CThe type of beaker used
4. DThe reaction rate

Which is larger, a sodium atom (Na) or a sodium ion (Na⁺)?

1. AIt depends on the temperature
2. BThe sodium ion
3. CThe sodium atom
4. DThey are the same size

According to the Brønsted–Lowry definition, what is an acid?

1. AA proton (H⁺) acceptor
2. BA proton (H⁺) donor
3. CA hydroxide ion donor
4. DAn electron pair donor

Pepsin digests protein in the stomach at about pH 2, but it stops working once food moves into the small intestine, where the pH is higher. Why?

1. APepsin is used up completely in the stomach, just like a reactant
2. BThe change in pH alters the shape of pepsin's active site
3. CPepsin only works on fats in the small intestine
4. DThe small intestine is too cold for any enzyme

Which compound contains both ionic and covalent bonds?

1. ASodium sulfate, Na₂SO₄
2. BSodium chloride, NaCl
3. CMethane, CH₄
4. DWater, H₂O