护理入学考试化学练习卷（附答案）

What is an acid–base indicator?

1. AA substance that changes colour depending on pH
2. BA device that measures temperature
3. CA gas given off by acids
4. DA substance that neutralises every acid

哪种气体构成了地球空气的大部分？

1. A氧气
2. B二氧化碳
3. C氢气
4. D氮气

Which of these is a polyatomic ion?

1. AOxide, O²⁻
2. BSodium, Na⁺
3. CSulfate, SO₄²⁻
4. DChloride, Cl⁻

下列哪项描述的是强酸？

1. A它只部分释放氢离子
2. B它总是浓度很高
3. C它在水中完全电离
4. D它的 pH 高于 7

What is the molar mass of sulfuric acid, H₂SO₄ (H = 1, S = 32, O = 16 g/mol)?

1. A50 g/mol
2. B96 g/mol
3. C98 g/mol
4. D49 g/mol

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. AAbout 36 g dissolves and about 14 g stays undissolved
2. BAll 50 g dissolves
3. CAbout 14 g dissolves and about 36 g stays undissolved
4. DNone of the salt dissolves

J.J. Thomson's cathode ray experiments led to which discovery?

1. AAtoms contain small, negatively charged particles
2. BAtoms have a dense, positively charged nucleus
3. CElectrons occupy fixed energy levels
4. DThe nucleus contains uncharged neutrons

Which statement correctly distinguishes a scientific law from a scientific theory?

1. ALaws apply only to chemistry, theories only to biology
2. BA law describes what happens; a theory explains why it happens
3. CA law is only a guess, while a theory is a proven fact
4. DA theory becomes a law once it is proved