Chapter 1-8: Key Vocabulary for Measurements and Units (Chemistry)

Vocabulary flashcards covering units, measurement concepts, accuracy vs. precision, uncertainty, Kelvin/Celsius, density, conversion factors, significant figures, and related topics from the lecture notes.

Unit

The label that tells you what quantity a number represents (e.g., cm, g, s); without a unit, a number has no meaning.

Measurement

A quantity that includes a number, a unit, and often an uncertainty describing its precision.

Uncertainty

The ± value attached to a measurement indicating the possible range of the true value and reflecting precision.

Accuracy

Closeness of a measurement to the true or accepted value.

Precision

How close a set of measurements are to each other.

Accepted value

The true value used as a reference for judging accuracy.

Kelvin

A temperature scale used in chemistry; an absolute scale frequently used by chemists.

Celsius

A temperature scale used in chemistry; commonly used alongside Kelvin.

Fahrenheit

A temperature scale that chemists generally do not use.

Measurement quantities

Quantities commonly measured in chemistry, such as length, mass, time, and temperature.

Density

A physical property defined as mass per volume; SI unit is kg/m^3.

Conversion factor

A ratio used to convert from one unit to another (e.g., 1 kg = 1000 g) enabling dimensional analysis.

Mass

A measure of the amount of matter in an object; commonly measured in grams or kilograms.

Volume

The amount of space occupied by a substance; common units include cm^3 and L.

Significant figures

The meaningful digits in a measurement that reflect its precision; used to express uncertainty.

Uncertainty notation example

A representation such as 12.0 cm ± 0.2 cm showing the precision of a measurement.

Four basic measurable quantities

Length, mass, time, and temperature—fundamental things you measure in chemistry.

Conductivity

A property that describes how well a material conducts electric current.