Unit 1: Matter and Measurement Study Guide

Vocabulary flashcards covering core matter classification, physical and chemical changes, separation methods, and scientific measurement concepts from the Unit 1 Study Guide.

Law of Conservation of Mass

A fundamental scientific law stating that in any physical change or chemical reaction, mass is neither created nor destroyed; the total mass of the reactants equals the total mass of the products.

Matter

Anything that has mass and takes up space.

Mass

A measure of the amount of matter that an object contains.

Substance

Matter that has a uniform and definite composition; also known as a pure substance.

Element

The simplest form of matter that has a unique set of properties and cannot be broken down into simpler substances by chemical means.

Compound

A substance that contains two or more elements chemically combined in a fixed proportion; it can be broken down into simpler substances by chemical changes.

Physical property

A quality or condition of a substance that can be observed or measured without changing the substance's chemical composition (e.g., melting point, density, color).

Chemical property

The ability of a substance to undergo a specific chemical change and form new substances (e.g., reactivity with oxygen).

Physical change

A change during which some properties of a material alter, but the chemical composition of the material remains unchanged (e.g., melting, cutting, grinding).

Chemical change

A change that produces matter with a different composition than the original matter, involving the rearrangement of atoms into new substances (e.g., rusting, decaying).

Solid

A state of matter that has a definite shape and a definite volume.

Liquid

A state of matter that has an indefinite shape, flows, yet has a fixed volume.

Gas

A state of matter that takes both the shape and the volume of its container, lacking a definite shape or definite volume.

Vapor

The gaseous state of a substance that generally exists as a solid or liquid at room temperature.

Reactant

A starting substance present at the beginning of a chemical reaction.

Product

A substance that is produced as a result of a chemical reaction.

Mixture

A physical blend of two or more components that are not chemically combined and can be separated by physical processes.

Solution

A homogeneous mixture of two or more substances consisting of a single phase, in which solute particles are uniformly dispersed within a solvent.

Solute

The dissolved substance in a solution.

Solvent

The dissolving medium in a solution.

Homogeneous mixture

A mixture in which the composition is uniform throughout, consisting of only a single phase.

Heterogeneous mixture

A mixture in which the composition is not uniform throughout, consisting of two or more distinct phases.

Phase

Any part of a sample with uniform composition and properties.

Chromatography

A physical separation technique that separates the components of a mixture based on the relative tendency of each substance to travel across the surface of another material.

Filtration

A physical process that separates a solid from a liquid in a heterogeneous mixture.

Distillation

A physical separation process in which a liquid is boiled to produce a vapor that is then condensed into a liquid to separate it from other components.

Chemistry

The scientific study of the composition, structure, properties, and changes of matter.

Scientific Notation

An expression of numbers in the form $m \times 10^n$, where $m$ is a coefficient greater than or equal to $1$ and less than $10$, and $n$ is an integer exponent.

Significant Figures

All the digits in a measurement that are known precisely, plus one final estimated digit.

Metric System

A decimal-based measurement system organized around multiples of $10$.

SI Unit

The International System of Units (Le Système International d'Unités), the standard modern metric system used worldwide by scientists.

Accuracy

A measure of how close a measured value comes to the actual, true, or accepted value of the quantity measured.

Precision

A measure of how close a series of measurements of the same item are to one another.

Mega-

A metric prefix denoting a factor of $10^6$ ($1\,000\,000$ times the base unit).

Kilo-

A metric prefix denoting a factor of $10^3$ ($1000$ times the base unit).

Deci-

A metric prefix denoting a factor of $10^{-1}$ ($\frac{1}{10}$ of the base unit).

Centi-

A metric prefix denoting a factor of $10^{-2}$ ($\frac{1}{100}$ of the base unit).

Milli-

A metric prefix denoting a factor of $10^{-3}$ ($\frac{1}{1000}$ of the base unit).

Conversion Factor

A ratio of equivalent values expressed with different units used to convert a quantity from one unit to another.

Kelvin

The SI base unit of temperature, based on absolute zero, where water freezes at $273.15\,\text{K}$ and which contains no negative temperature values.

Absolute zero

The zero point on the Kelvin temperature scale ($0\,\text{K}$ or $-273.15\,^\circ\text{C}$), representing the temperature at which all molecular motion theoretically ceases.

Density

An intensive physical property representing the ratio of the mass of an object to its volume, calculated as $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.