Chapter 1: Matter and Energy Lecture Notes

Vocabulary flashcards covering the definitions of matter, energy, classification of substances, physical/chemical changes, and scientific inquiry from Chapter 1.

Matter

Anything that occupies space and has mass.

Energy

The capacity to do work or to transfer heat.

Pure Substances

Matter that has a uniform chemical composition throughout and from sample to sample.

Mixtures

Composed of two or more pure substances and may or may not have uniform composition.

Element

A substance that cannot be broken down into simpler substances even by a chemical reaction.

Compound

A substance composed of two or more elements combined in definite proportions.

Metals

Elements distinguished by their luster and ability to conduct electricity.

Nonmetals

Elements that are usually dull in appearance and poor conductors of electricity; includes gases at room temperature.

Atom

The smallest unit of an element that retains the chemical properties of that element.

Molecules

Two or more atoms bound together in a discrete arrangement.

Homogeneous Mixtures (Solutions)

Mixtures that have the same composition throughout.

Heterogeneous Mixtures

Mixtures that do not have uniform composition throughout.

Solid

A state of matter with a fixed shape and its own volume; particles are fixed in a regular array.

Liquid

A state of matter that takes the shape of its container and has its own volume; particles are randomly arranged and free to move.

Gas

A state of matter that fills the shape and volume of its container; particles are widely separated and move independently.

Physical Property

A characteristic that can be observed without changing the composition of a substance, such as color, mass, or volume.

Physical Change

A process that changes the physical properties of a substance without changing its chemical composition, such as a change of state.

Chemical Change

A process where one or more substances are converted into one or more new substances; also called a chemical reaction.

Chemical Property

A description of the ability of a substance to undergo a chemical change.

Kinetic Energy

The energy of motion.

Potential Energy

Energy possessed by an object because of its position; stored energy.

Scientific Method

An approach to asking questions and seeking answers that includes observations, hypotheses, laws, and theories.

Hypothesis

A tentative explanation for the properties or behavior of matter that accounts for a set of observations and can be tested.

Scientific Law

Describes the way nature operates under a specified set of conditions.

Theory

Explains why observations, hypotheses, or laws apply under many different circumstances.

Precision

The extent of the agreement between repeated measurements of a value.

Accuracy

The difference between the value of a measured number and its expected or correct value.

Significant Figures

Digits in a measurement that represent the certainty of the value; includes all non-zero digits and specific zero placements.

Mass

Measures the quantity of matter; common units are grams ($g$).

Volume

The amount of space a substance occupies; calculated as $\text{length} \times \text{width} \times \text{height}$.

Density

The ratio of the mass of a substance to its volume, measured in $g/mL$ or $g/cm^{3}$ for solids/liquids.

Scientific Notation

A number written in the form $C \times 10^{n}$, where $C$ is a coefficient between 1 and 10, and $n$ is an exponent.

Sublimation

The physical state transition from a solid directly to a gas.

Deposition

The physical state transition from a gas directly to a solid.