Chemistry Chapter 1 Reading Notes (copy)

Chemistry

The study of matter and its properties, how matter changes, and how these changes are accompanied by energy changes.

Matter

Anything that has mass and occupies space.

Scientific Method

A systematic approach to research involving observation, hypothesis, experimentation, law, and theory.

Observation

Gathering qualitative and quantitative data.

Hypothesis

A tentative explanation for observations that can be tested through experimentation.

Experiment

Procedures designed to test a hypothesis; must be controlled and reproducible.

Law

A concise statement or mathematical equation summarizing experimental observations and describing a natural phenomenon.

Theory

A well-substantiated, comprehensive, and testable explanation of a particular aspect of nature.

Solid

A state of matter with a definite shape and volume where particles are closely packed in fixed positions.

Liquid

A state of matter with a definite volume but indefinite shape; particles can move past each other.

Gas

A state of matter with indefinite shape and volume; particles are far apart and move randomly.

Plasma

A gaseous state containing significant numbers of electrically charged particles (ionized atoms or molecules).

Pure Substances

Matter with a fixed composition and distinct properties.

Elements

Substances that cannot be broken down into simpler substances by chemical means, composed of only one type of atom.

Compounds

Two or more different elements chemically bonded together in fixed proportions.

Mixtures

Two or more substances physically combined, each retaining its own chemical identity.

Homogeneous Mixture (Solution)

A mixture with uniform composition and properties throughout.

Heterogeneous Mixture

A mixture with non-uniform composition where components are visibly distinct.

Atoms

The smallest particle of an element that retains the chemical identity of the element.

Molecules

Two or more atoms joined together by chemical bonds.

Physical Properties

Characteristics of matter that can be observed or measured without changing the substance's chemical identity.

Physical Change

A change in the state or properties of matter without altering its chemical composition.

Chemical Properties

Characteristics that describe a substance's ability to undergo specific chemical changes or reactions.

Chemical Change (Chemical Reaction)

A process producing one or more new substances that differ from the original substances.

Extensive Properties

Properties that depend on the amount of matter present.

Intensive Properties

Properties that do not depend on the amount of matter present.

SI Units (International System of Units)

The standard system of units used globally in science.

Derived Units

Units obtained from combinations of base units.

Volume

A common derived unit; 1 L = 1000 mL = 1000 cm^3 = 1 dm^3.

Density (d)

A physical property defined as mass per unit volume (d = m/V).

Significant Figures (Sig Figs)

The number of meaningful digits in a measured quantity.

Accuracy

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

Precision

How closely multiple measurements agree with one another.

Dimensional Analysis (Factor-Label Method)

A problem-solving technique that uses conversion factors to convert units.

Conversion Factor

A ratio of equivalent measurements expressing the same quantity in different units.