Introduction to Chemistry and Dalton's Atomic Theory

These flashcards provide definitions for foundational chemistry concepts including the properties of matter, classification of substances, measurement standards (accuracy, precision, and significant figures), and the historical development of atomic theory and the laws of matter.

Chemistry

The study of what matter is made and how it changes.

Tabir Ibn Hayyan

A scientist known as the Father of Chemistry.

Matter

Everything that has weight and takes up space or has volume.

Solid

A physical state of matter where particles are tightly packed with ordered arrangements.

Liquid

A physical state of matter where particles are close together but loosely bonded.

Gas

A physical state of matter where particles are separated and move freely.

Physical Property

A characteristic of matter that can be observed without changing the identity of the matter, such as color, shape, texture, volume, or temperature.

Chemical Property

A characteristic that can only be observed when the matter changes into new matter, such as its reaction to acid, base, or water.

Freezing Point

The temperature at which a liquid changes to a solid.

Melting Point

The temperature at which a solid changes to a liquid.

Boiling Point

The temperature at which matter changes from liquid to a gas.

Condensation

The temperature at which a gas changes to a liquid.

Intensive Property

A property of matter that does not change regardless of the amount of substance present, such as color, temperature, or density.

Extensive Property

A property of matter that changes when the amount of the substance changes, such as mass, volume, length, or weight.

Mixture

Two or more substances that are mixed together.

Pure Substance

Matter that has a fixed chemical composition and distinct properties.

Heterogeneous Mixture

A mixture where the components separate and the composition varies.

Homogeneous Mixture

A mixture where the composition of its constituents is uniformly mixed throughout.

Element

A substance that cannot be broken down chemically into simpler components and consists of one kind of atom.

Compound

A substance composed of two or more elements.

Accuracy

How close a measurement is to the true or accepted value.

Precision

How close repeated measurements are to each other, indicating consistency.

Significant Figures

The numbers that matter when writing measurements.

Non-zero Digits (Sig Fig Rule)

All digits that are not zero are always considered significant.

Leading Zeros (Sig Fig Rule)

Zeros to the left of the first non-zero digit are not significant.

Captive Zeros (Sig Fig Rule)

Zeros between non-zero digits are considered significant.

Trailing Zeros in a Whole Number (Sig Fig Rule)

Zeros to the right of the last non-zero digit are NOT considered significant unless explicitly indicated.

Trailing Zeros in a Decimal Number (Sig Fig Rule)

Zeros to the right of the last non-zero digit in a decimal are considered significant.

Scientific Notation (Sig Fig Rule)

When a number is expressed in scientific notation, all digits in the coefficient are significant.

Democritus

An ancient Greek philosopher (around $400\,BC$) who proposed that all matter is made of tiny, solid, invisible particles called atoms.

Law of Conservation of Mass

A law proposed by Antoine Lavoisier in $1789$ stating that matter cannot be created or destroyed, only changed in form.

Law of Definite Composition

A law proposed by Joseph Proust stating that a pure compound always has the same elements in the exact same ratio by mass.

Law of Multiple Proportions

A law proposed by John Dalton in the $1800s$ stating that if two elements combine to form more than one compound, the masses combine in small whole-number ratios.

Dalton's Atomic Theory (Atoms)

Postulate stating all matter, whether an element, compound, or mixture, is made of tiny particles called atoms.

Dalton's Atomic Theory (Identity)

Postulate stating all atoms of a given element are identical in size, mass, and chemical properties.

Dalton's Atomic Theory (Indivisibility)

Postulate stating atoms are indivisible particles that cannot be created or destroyed in a chemical reaction; they only rearrange.