Chemistry · Ch 1 — Some Basic Concepts of Chemistry
Properties of matter and their measurement
Properties of matter and their measurement
Every kind of matter has its own set of characteristic properties, and these fall into two broad categories: physical properties and chemical properties. A physical property is one that can be measured or observed WITHOUT changing the substance's chemical composition — colour, odour, melting point, boiling point and density are all physical properties, since observing them leaves the substance chemically unchanged. A chemical property, in contrast, is one where the substance actually undergoes a chemical change and, in doing so, its chemical composition is altered — for example, coal burns in air to form carbon dioxide, or a magnesium wire burns in the presence of oxygen to form magnesium oxide (ill …
What this figure shows. A photographic figure showing a strip or coiled wire of magnesium metal burning in air with a characteristically brilliant white flame. It illustrates a CHEMICAL property/change: magnesium metal reacts with atmospheric oxygen — a chemical change that alters the substance's composition — to form magnesium oxide, a new substance with different properties from the original metal. The text uses it as the concrete example accompanying the definition of a chemical property, in contrast with physical properties (such as colour or melting point) which can be obser …