Composition of Mixtures · 混合物的组成
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| mixture/ˈmɪkstʃə/ | 混合物 | hùn hé wù |
| mass percent/mæs pəˈsent/ | 质量分数 | zhì liàng fēn shù |
When things are blended
- Salt water can be barely salty or nearly saturated.
- Unlike a pure compound, a blend has no fixed recipe.
- You can have any amount of each ingredient.
- To describe a blend, we measure how much of each part it holds.
当东西被混合时
- 盐水可以只有一点点咸,也可以接近饱和。
- 与纯化合物不同,混合物没有固定的配方。
- 每种成分都可以是任意的量。
- 要描述一份混合物,我们测量它含有每一部分多少。
Blends have no fixed formula
- A mixture 混合物 contains two or more substances in variable amounts.
- Each keeps its own identity and can be separated physically.
- Air, seawater, and steel are all mixtures.
混合物没有固定化学式
- 混合物含有两种或更多物质,量是可变的。
- 每种成分保持自己的身份,可以用物理方法分开。
- 空气、海水、钢都是混合物。
A mixture can have different proportions from one sample to another. · 混合物在不同样本中的比例可能不同。
Mixtures have variable composition, unlike pure compounds. · 混合物具有可变的组成，而纯化合物则不然。
The components of a mixture can generally be separated by... · 混合物的组分通常可以通过……分离。
Components keep their identity and separate physically (filtering, distilling). · 组分保持其原有性质并可通过物理方式分离（过滤、蒸馏等）。
Select all · 所有 that are mixtures. · 选择所有属于混合物的选项。
Seawater, air, and brass are mixtures; pure water is a compound. · 海水、空气和黄铜是混合物；纯水是化合物。
Mass percent of a component
- The mass percent 质量分数 of a component is:
- It tells you the concentration by weight.
某成分的质量分数
- 某成分的质量分数是:
- 它告诉你按重量计的浓度。
Element, compound or mixture? · 元素、化合物还是混合物？
Sort each sample into element, compound or mixture. · 将每个样本分类为元素、化合物或混合物。
A $200\ \text{g}$ solution is 15% sugar by mass. The mass of sugar (in g)? · 一种$200\ \text{g}$溶液含糖量为 15%（质量分数）。糖的质量是多少（单位 g）？
$0.15 \times 200 = 30\ \text{g}$.
An alloy is 60% iron and the rest carbon. The mass percent of carbon (in %)? · 某合金含 60% 的铁，其余为碳。碳的质量百分比（单位 %）是多少？
Percents sum to 100, so carbon is $100 - 60 = 40\%$. · 百分数总和为 100，因此碳的含量为$100 - 60 = 40\%$。
Working backward to amounts
- Knowing the total mass and one part's percent gives that part's mass.
- A reaction can reveal a hidden component's amount.
- Molar masses then convert those masses into moles.
反推各成分的量
- 知道总质量和某一部分的百分比,就得到那一部分的质量。
- 一个反应可以揭示某隐藏成分的量。
- 摩尔质量再把这些质量化成摩尔。
A sample holds $24\ \text{g}$ of carbon (molar mass 12). How many moles of carbon? · 某样本含有$24\ \text{g}$碳（摩尔质量 12）。碳的摩尔数是多少？
$n = m/M = 24/12 = 2\ \text{mol}$.
A $50\ \text{g}$ alloy is 30% copper by mass.
- Mass of copper: $0.30 \times 50 = 15\ \text{g}$.
- The remaining $35\ \text{g}$ is the other metal.
一块 $50\ \text{g}$ 的合金按质量含 30% 的铜。
- 铜的质量:$0.30 \times 50 = 15\ \text{g}$。
- 剩下的 $35\ \text{g}$ 是另一种金属。
A mixture's percent composition is not fixed -- it changes from sample to sample, unlike a pure compound. The mass percents of all components must add to 100%. And keep the mixture's total mass separate from any single component's molar mass; they play different roles.
混合物的百分组成不固定——它因样品而异,这与纯化合物不同。所有成分的质量分数必须加起来等于 100%。而且要把混合物的总质量与任何单一成分的摩尔质量分开;它们的作用不同。
A mixture holds two or more substances in variable amounts, each keeping its identity. The mass percent of a component is its mass over the mixture's mass, times 100. Because the total is fixed, the components' percents sum to 100%, and molar masses turn any component mass into moles.
混合物含有两种或更多物质、量可变,每种都保持自身身份。某成分的质量分数是它的质量除以混合物的质量再乘 100。由于总量固定,各成分的百分比之和为 100%,而摩尔质量能把任何成分质量化成摩尔。