Pure Substances and Mixtures

30 vocabulary flashcards covering key terms and ideas from the lecture on pure substances and mixtures.

Pure Substance

A form of matter that cannot be separated by physical or ordinary chemical means and has a fixed composition.

Mixture

A combination of two or more substances that can be separated by physical means, with each substance retaining its own properties.

Element

The simplest type of pure substance, composed of only one kind of atom.

Atom

The smallest particle of an element that still retains the properties of that element.

Compound

A pure substance formed when two or more elements chemically combine in fixed proportions.

Molecule

The smallest unit of a compound (or some elements) that retains all the chemical properties of that substance.

Fixed Composition

A characteristic of pure substances in which the ratio of components is constant throughout.

Chemical Combination

The process by which atoms of elements bond to form compounds, producing new substances.

Physical Separation

Any non-chemical method (e.g., filtration, evaporation) used to separate components of a mixture.

Ordinary Chemical Means

Common laboratory reactions that can break down compounds but cannot separate elements further.

Hydrogen

A colorless, odorless element that bonds with oxygen to form water.

Oxygen

A gaseous element essential for combustion and a component of water.

Water (H₂O)

A compound consisting of two hydrogen atoms and one oxygen atom; often called the universal solvent.

Salt (NaCl)

A compound of sodium and chlorine widely used as table salt and preservative.

Sodium

A soft, highly reactive metal that forms the cation in table salt.

Chlorine

A yellow-green poisonous gas that forms the anion in table salt.

Gold

A yellow, malleable metallic element that exists naturally as a pure substance.

Aluminum

A lightweight, shiny, silver metal commonly used in foils and beverage cans.

Malleable

A physical property describing a substance that can be hammered or rolled into thin sheets without breaking.

Shiny (Luster)

The property of reflecting light, giving a glossy surface typical of many metals.

Properties of Matter

Characteristics such as color, luster, malleability, and density that describe how a substance looks and behaves.

Classification of Matter

The organization of material into pure substances (elements & compounds) and mixtures.

Pure Substance Examples

Common examples include gold, water, and oxygen.

Element Examples

Aluminum and gold are representative examples of elements.

Compound Examples

Water and salt are typical examples of compounds.

Form of Matter

Any physical material that occupies space and has mass.

Individual Properties

The unique characteristics an element has before it chemically combines with other elements.

New Properties (of Compounds)

The distinct traits that emerge after elements chemically combine, often different from those of the original elements.

Brainy Challenge Question

“What happens when substances are mixed?”—a prompt encouraging exploration of mixtures.

Physical vs. Chemical Means

The distinction between separating mixtures physically and breaking compounds chemically.