IB Chemistry: Types and States of Matter | IB化学：物质的类型与状态详解

📚 IB Chemistry: Types and States of Matter | IB化学：物质的类型与状态详解

In IB Chemistry, understanding the types and states of matter is fundamental to every later topic. This article explains how matter is classified, how its physical state is determined, and why changes of state occur.

在IB化学中，理解物质的类型和状态是后续所有主题的基础。本文将解释物质如何分类、其物理状态如何决定，以及状态变化为何发生。

1. Matter and Classification | 物质与分类

Matter is classified by its composition and whether its components are chemically combined.

物质根据其组成以及组分是否发生化学结合进行分类。

A pure substance has a fixed composition and distinct properties. It can be an element or a compound.

纯净物具有固定的组成和独特的性质。它可以是元素或化合物。

A mixture consists of two or more substances that are physically intermingled but not chemically combined.

混合物由两种或多种物质物理混合而成，但并未发生化学结合。

Mixtures are either homogeneous (uniform throughout, e.g. salt water) or heterogeneous (visible distinct phases, e.g. sand and iron filings).

混合物可以是均一的（整体均匀，如盐水）或非均一的（可见不同相态，如沙子和铁屑）。

2. Elements, Compounds and Mixtures | 元素、化合物与混合物

Elements are substances that contain only one type of atom. Oxygen gas (O₂) is an element.

元素是只含一种原子的物质。氧气（O₂）是元素。

Compounds are substances formed when atoms of different elements combine in fixed ratios. Water (H₂O) is a compound.

化合物是由不同元素的原子按固定比例结合形成的物质。水（H₂O）是化合物。

Mixtures contain two or more substances that can be separated by physical methods, such as filtration, distillation or chromatography.

混合物含有两种或多种物质，可通过过滤、蒸馏或色谱等物理方法分离。

In a mixture, each component keeps its own chemical identity; in a compound, the components lose their original properties.

在混合物中，各组分保持自身化学性质；在化合物中，组分失去原有性质。

3. Chemical Symbols and Formulae | 化学符号与化学式

Chemical symbols are shorthand for elements, e.g. Na for sodium, Cl for chlorine.

化学符号是元素的简写，例如 Na 代表钠，Cl 代表氯。

Chemical formulae show the ratio of atoms in a compound. For example, H₂O contains two hydrogen atoms and one oxygen atom.

化学式表示化合物中原子的比例。例如 H₂O 含有两个氢原子和一个氧原子。

Molecular substances use subscripts to show the actual number of atoms in a molecule, e.g. CO₂, NH₃.

分子物质用下标表示分子中实际原子数目，例如 CO₂、NH₃。

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