Chapter 1: An Introduction to Chemistry

Chem 30A

Chemistry

The study of the structure and behavior of matter

Value

A number and a unit that together represent the result of a measurement or calculation. The distance of a particular race, for example, may be reported as a value of 100 meters

Unit

A defined quantity based on a standard. For example, in the value 100 meters, meters is the unit

Base Units

The seven units from which all other units in the SI system of measurment are derived

Mass

The amount of matter in an object. Mass can also be defined as the property of matter that leads to gravitational attractions between objects and therefore gives rise to weight.

Weight

A measure of the force of gravitational attraction between an object and a significantly large object, such as the moon or Earth.

Matter

Anything that has mass and ocupies space.

Absolute Zero

Zero Kelvin (0 K), the lowest possible temperature, equivalent to -273.15C. It is the point beyond which motion can be detected.

Precision

The closeness in value of a series of measurements of the same entity. The closer the values of the measurements, the more precise they are. How

Accuracy

How closely ameasured value approaches the true value of a property.