solid, liquid, and gas
is the phase or state of matter. The three fundamental phases of matter are solid, liquid, and gas see Figure 1.1 "The Phases of Matter" . Chemical properties are characteristics of matter that describe how matter changes form in the presence of other matter. Does a sample of matter burn? Burning is a chemical property. Does it behave violently when put in water? This reaction is a chemical property as well Figure 1.2 "Chemical Properties" . In the following chapters, we will see how descriptions of physical and chemical properties are important aspects of chemistry. If matter always stayed the same, chemistry would be rather boring. Fortunately, a major part of chemistry involves change. A physical change occurs when a sample of matter changes one or more of its physical properties. For example, a solid may melt Figure 1.3 "Physical Changes" , or alcohol in a thermometer may change volume as the temperature changes. A physical change does not affect the chemical composition of matter. A chemical change is the process of demonstrating a chemical property, such as the burning match in Figure 1.2 "Chemical Properties". As the matter in the match burns, its chemical composition changes, and new forms of matter with new physical properties are created. Note that chemical changes are frequently accompanied by physical changes, as the new matter will likely have different physical properties from the original matter.