护理入学考试化学练习卷（附答案）

How is percent yield calculated?

1. A(Actual yield ÷ theoretical yield) × 100
2. B(Mass of reactants ÷ mass of products) × 100
3. CActual yield − theoretical yield
4. D(Theoretical yield ÷ actual yield) × 100

下列哪一项是物理变化？

1. A牛奶变酸
2. B铁生锈
3. C面包烤成褐色
4. D水沸腾变成水蒸气

What are the units of molarity?

1. AMoles of solute per kilogram of the solvent used
2. BGrams of solute per 100 g of solution
3. CGrams of solute per litre of solution (g/L)
4. DMoles of solute per litre of solution (mol/L)

下列哪项描述的是吸热过程？

1. A它只在非常高的温度下发生
2. B它既不吸收也不释放任何能量
3. C它释放热量，所以周围环境感觉更暖
4. D它吸收热量，所以周围环境感觉更冷

A reaction has a theoretical yield of 20 g, but only 15 g of product is collected. What is the percent yield?

1. A75%
2. B5%
3. C25%
4. D133%

Which nuclear process powers the Sun?

1. AFusion of hydrogen nuclei to form helium
2. BAlpha decay of helium
3. CFission of uranium into smaller nuclei
4. DCombustion of hydrogen gas with oxygen in its core

将 2 mol H₂ 和 2 mol O₂ 混合，按 2H₂ + O₂ → 2H₂O 反应。哪种反应物是限量试剂？

1. A都不是，因为量相等
2. B水，因为它是产物
3. C氢气，因为 2 mol H₂ 只用掉 1 mol O₂
4. D氧气，因为氧气比氢气少

Why is gamma radiation used to sterilise sealed medical supplies such as syringes?

1. AIt heats the items to very high temperatures, so the microbes are burned away inside the pack
2. BIt is stopped by the packaging, so it only cleans the outside
3. CIt adds a protective chemical coating to the items
4. DIt passes through the packaging and kills microbes without making the items radioactive