Ch 01 Chemistry & Measurements

Chemistry

The study of matter, its composition, structure, properties, reactions, and the energy involved in those reactions.

Matter

Anything that has mass (sometimes expressed as weight) and occupies space.

Chemicals

Substances that always have the same composition and properties, also referred to as substances.

Measurement

A comparison of some dimension of an object to a standard, usually expressed as a number followed by a unit.

Metric System

A decimal-based system of measurement used globally that includes meters, liters, and grams.

SI Units

The International System of Units, a modern form of the metric system that includes units like meter (m), liter (L), and kilogram (kg).

Scientific Notation

A method of expressing very large or very small numbers using powers of 10.

Significant Figures

The digits in a measurement that carry meaningful information about its precision.

Exact Numbers

Numbers obtained by counting or defined quantities that do not influence the number of significant figures in calculations.

Measured Numbers

Numbers obtained by using measuring devices; they include uncertainties.

Conversion Factor

A ratio that expresses how many of one unit are equal to another unit, used for converting between measurement systems.

Density

A measure of mass per unit volume of a substance, often expressed in grams per milliliter (g/mL) or grams per cubic centimeter (g/cm³).

Prefix (in Metric System)

A term placed before a unit to indicate fractional or multiple sizes, such as kilo- (thousand) or milli- (thousandth).

Equality

A statement that two different units represent the same quantity.

Rounding Off

The process of adjusting the digits of a number to reflect a certain number of significant figures.

Percent Factor

A ratio of parts to the whole expressed as a fraction of 100, often used in concentration calculations.

Significant Zeros

Zeros that are considered significant part of a number when determining precision.