Chemistry Lab/Physical Properties

Physical Properties is a projected new topic for Chemistry Lab in 2018.

Physical properties can be observed and measured without changing the composition of matter, just as physical changes occur without affecting the chemical composition of matter. Physical properties can range from a wide variety of topics; this wiki attempts to explain the most important physical properties.

The Materials Science page may also be useful for this topic, but many of the Materials Science topics are focused on the engineering standpoint of physical properties rather than the chemical standpoint.

Types of Properties
Chemical properties of matter describe its ability to undergo various reactions or chemical changes. Chemical properties require experimentation to discover, and are not readily apparent based on a material itself. For example, flammability is a chemical property, which describes how readily a material burns. Corrosivity is another chemical property, describing how readily a material reacts with oxygen and rusts.

Physical properties, meanwhile, can be observed based on a material itself. They do not require a reaction to be tested. Physical properties can further be divided into extensive properties, which depend on the amount of matter in a system, and intensive properties, which depend only on the material itself. For example, mass is an extensive property, while density is intensive.

Intensive Properties
As described above, intensive properties do not depend on the amount of a material.

Some basic intensive properties include temperature, pressure, and color.

Other more detailed intensive properties are described below.

Density
Density is an important property, especially when used to distinguish substances.

In the past, some Materials Science tests have included a density lab, which may also appear in future Chem Lab tests.

The formula for density is as follows: [math]D = m/V[/math]

Density therefore requires two measurements - mass, and volume.

Mass is fairly simple to measure, as most labs will provide fairly precise balances.

Volume may be calculated a number of ways. In some cases, a ruler or calipers can be used to measure the dimensions of fairly regular objects, such as rectangular prisms, cylinders, and spheres. Irregular objects can also be measured using the water displacement method, where the object is dropped into a known volume of water and the volume is measured from the change of water volume.

Competitors should also be able to use this equation in other directions, calculating either mass or volume from a known density and other value.

Extensive Properties
Extensive properties are affected by the amount of material.

Some basic extensive properties include mass and volume.

Other more detailed extensive properties are described below.