Particle Theory, Properties, and Classification of Matter

Vocabulary flashcards reviewing particle theory, states of matter, physical and chemical properties, physical and chemical changes, and the classification of matter into pure substances and mixtures.

Matter

Anything that has mass and takes up space (volume).

Solid

A state of matter where particles are held very tightly together by strong forces of attraction, have vibrational motion, cannot be easily compressed, and possess a definite shape and volume (rigid).

Liquid

A state of matter where particles are close together but can move with moderate forces of attraction, having a definite volume but no definite shape, and flowing freely without being easily compressed.

Gas

A state of matter where particles are far apart with little attraction, free to move quickly in all directions, have no definite shape or volume, expand to fill any container, and can be easily compressed.

Physical Property

A characteristic or description of a substance that may help to identify it, observed or measured without forming a new substance.

Qualitative Physical Properties

Properties of a substance that can be observed directly with the senses, such as physical state, odour, colour, texture, and lustre.

Quantitative Physical Properties

Properties of a substance that are measured and given a numerical value, such as mass, volume, and temperature.

Clarity

A qualitative physical property describing how much light passes through an object: transparent (clear), translucent (cloudy), or opaque (no light passes through).

Lustre

A qualitative physical property describing the ability of an object to reflect light, ranging from dull to shiny (high lustre).

Malleability

The ability of a substance to be hammered or bent into different shapes without breaking.

Brittle

The ability of an object to break apart or shatter easily, as opposed to being flexible.

Ductility

The ability of a substance to be stretched into wire.

Melting Point

The temperature at which a substance changes its state from a solid to a liquid.

Viscosity

The measure of how easily a liquid flows; a substance that does not flow easily (like honey) has a high viscosity.

Solubility

The ability of a substance to dissolve in another substance.

Hardness

The resistance of a substance to being scratched, evaluated on a scale of $1$ to $10$, with diamond being rated as a $10$.

Conductivity

The ability of a substance to conduct or transfer electricity or heat.

Density

The amount of matter that occupies a certain amount of space.

Chemical Property

The ability of a substance to change (react) and form new substances.

Combustibility

A chemical property that describes the ability of a substance to burn in air, requiring oxygen to do so.

Reactivity

A chemical property describing the ability of a substance to react easily with other substances, such as air, water, or acid.

Light Sensitivity

A chemical property where a substance interacts with light to form new substances (such as hydrogen peroxide changing into water and oxygen gas).

Physical Change

A change in which the composition of the substance remains the same and no new substances are produced (e.g., ice melting, dissolving sugar, chopping wood).

Chemical Change

A change in the starting substance(s) that produces one or more new substances (e.g., fireworks, cooking/baking, burning).

Precipitate

A new solid that is formed inside a liquid as evidence of a chemical change.

Mixture

A combination of $2$ or more substances with different particles in varying proportions that can be separated by physical methods.

Solution (Homogeneous Mixture)

A mixture that is uniformly mixed and shows only $1$ visible phase (e.g., Kool-Aid, coffee, milk, salt + water, stainless steel).

Mechanical Mixture (Heterogeneous Mixture)

A mixture in which $2$ or more phases are visible (e.g., oil + water, vegetable soup, cereal + milk, can of fizzy pop, chocolate chip cookie).

Pure Substance

A category of matter composed of only $1$ type of substance ($1$ type of particle) that can be written with a chemical symbol or formula and cannot be separated by physical methods.

Element

A pure substance consisting of only $1$ type of particle called an atom, which cannot be broken down to simpler forms, is found on the Periodic Table, and is written as a symbol (e.g., sodium = $\text{Na}$, gold = $\text{Au}$).

Compound

A pure substance composed of $2$ or more elements combined, which can be separated using chemical methods or reactions and is written as a chemical formula (e.g., salt: $\text{NaCl}$, water: $\text{H2O}$).