Introduction to Chemistry: Matter, Measurement, and Properties

Vocabulary practice flashcards covering fundamental chemistry principles, classification of matter, properties, SI units, measurements, density, scientific notation, and accuracy versus precision.

Matter

Anything that occupies space and has mass.

Chemistry

The science that studies the structure of matter and its transformations.

Pure substance

A substance with a constant, fixed composition and distinct properties (e.g., pure water).

Mixture

A combination of two or more pure substances in which each substance retains its distinct chemical identity.

Homogeneous mixture

A mixture with a uniform composition throughout, such as a solution of salt ($NaCl$) in water.

Heterogeneous mixture

A mixture with a non-uniform composition throughout, such as a mixture of oil and water.

Element

A substance that cannot be broken down into simpler substances by chemical means.

Compound

A substance composed of atoms of two or more element species chemically bound in definite proportions, which can only be separated by chemical methods.

Classification of Matter

The organization of matter into mixtures (homogeneous and heterogeneous) and pure substances (compounds and elements), showing how they are separated by physical or chemical methods.

Physical property

A property that can be measured or observed without changing the composition or identity of a substance.

Chemical property

A property whose observation or measurement requires a chemical transformation to occur.

Extensive property

A property that depends on the amount of matter being examined.

Intensive property

A property that does not depend on the amount of matter being examined.

SI Base Units

The standard international system of units: length in meters ($m$), mass in kilograms ($kg$), time in seconds ($s$), electric current in amperes ($A$), temperature in kelvins ($K$), amount of substance in moles ($mol$), and luminous intensity in candelas ($cd$).

SI Prefixes

Prefixes used to scale units: Mega ($M = 10^6$), Kilo ($k = 10^3$), Deci ($d = 10^{-1}$), Centi ($c = 10^{-2}$), and Milli ($m = 10^{-3}$).

Mass

A measure of the quantity of matter that constitutes an object; its SI unit is the kilogram ($kg$), though grams ($g$) are commonly used ($1\,kg = 1000\,g$).

Weight

The force exerted by gravity on an object.

Volume

A derived unit equal to length cubed ($m^3$), commonly measured using liters ($L$) where $1\,L = 10^{-3}\,m^3$ ($1000\,cm^3 = 1000\,mL = 1\,dm^3 = 1\,L$).

Density

An intensive property defined as mass divided by volume ($\rho = \frac{\text{mass}}{\text{volume}}$), typically expressed in $g/cm^3$ for solids and liquids and $g/L$ for gases ($1\,g/cm^3 = 1\,g/mL = 1000\,kg/m^3$).

Kelvin temperature scale

The SI temperature scale where absolute zero is $0\,K$ ($-273.15\,^\circ C$), the freezing point of water is $273.15\,K$ ($0\,^\circ C$), and the boiling point of water is $373.15\,K$ ($100\,^\circ C$).

Scientific notation

A notation expressing numbers in the form $N \times 10^n$, where $N$ is a number between 1 and 10 and $n$ is an integer exponent (e.g., $6.022045 \times 10^{23}$).

Significant figures

The meaningful digits in a measured or calculated quantity that reflect the precision of the measurement.

Accuracy

How close a measured result is to the true or accepted value of the quantity being measured.

Precision

The closeness of agreement among repeated measurements of the same quantity under identical conditions.

Accuracy and Precision Comparison

Target diagrams illustrating (a) accurate and precise results, (b) precise but inaccurate results caused by systematic error, and (c) results that are neither accurate nor precise.