Chapter 1: Matter, Measurement, and Problem Solving

Foundational vocabulary and concepts from Chapter 1 regarding matter, the scientific method, units of measurement, and significant figures.

Chemistry

The science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules.

Empirical

An approach to scientific knowledge based on observation and experiment.

Antoine Lavoisier

A scientist who observed that there was no change in the total mass of material within a container during combustion ($1743$–$1794$).

Hypothesis

A tentative interpretation or explanation of observations that is falsifiable.

Law

A brief statement that summarizes past observations and predicts future ones.

Law of conservation of mass

The principle stating that in a chemical reaction, matter is neither created nor destroyed.

Theory

A model that provides a general explanation for the characteristics and behavior of nature; they are validated by experiments but never conclusively proven.

Atoms

Submicroscopic particles that constitute the fundamental building blocks of matter.

Molecules

Particles formed when atoms bind together in specific geometrical arrangements.

Matter

Anything that occupies space and has mass.

Solid

A state of matter where atoms or molecules pack close to each other in fixed locations, resulting in a fixed volume and rigid shape.

Crystalline

A type of solid matter in which atoms or molecules are arranged in patterns with long-range, repeating order.

Amorphous

A type of solid matter in which atoms or molecules do not have any long-range order.

Liquid

A state of matter where atoms or molecules are close together but free to move relative to one another, resulting in a fixed volume but no fixed shape.

Gaseous

A state of matter where atoms or molecules have a lot of space between them, are free to move, and are compressible.

Pure substance

Matter made up of only one component with a fixed composition.

Mixture

A substance composed of two or more components in proportions that can vary from one sample to another.

Element

A pure substance that cannot be separated into simpler components.

Compound

A pure substance that can be separated into simpler substances, such as water or sugar.

Heterogeneous mixture

A mixture in which components can be identified and/or are unevenly distributed, like chocolate chip cookies.

Homogeneous mixture

A mixture that is uniformly distributed and cannot be easily identified, like jello or chocolate milk.

Decanting

The process of separating a mixture by carefully pouring off a liquid into another container.

Filtration

A process used to separate a mixture of an insoluble solid and a liquid by pouring it through filter paper in a funnel.

Distillation

A process of separating liquids with different boiling points by heating the mixture and cooling/collecting the resulting vapor.

Physical Change

An alteration that changes only the state or appearance of matter without changing the identity or composition of the atoms/molecules.

Chemical Change

An alteration that changes the composition of matter by transforming the original substance into something new through a chemical reaction.

Physical property

A characteristic a substance displays without changing its composition, such as odor, color, melting point, or density.

Chemical property

A characteristic a substance displays only by changing its composition via a chemical reaction, such as flammability or reactivity.

Intensive property

A property that is independent of the amount of substance present, such as boiling point, color, or temperature.

Extensive property

A property that depends on the amount of substance present, such as weight, volume, or moles.

Energy

The capacity to do work.

Work

The action of a force through a distance ($F=ma$).

Kinetic energy

Energy associated with the motion of an object.

Potential energy

Energy associated with the position or composition of an object.

Thermal energy

Energy associated with the temperature of an object.

Law of conservation of energy

The principle that energy is neither created nor destroyed during a physical or chemical change.

Mass

A measure of the quantity of matter within an object.

Weight

A measure of the gravitational pull on the matter of an object.

Temperature

A measure of the average amount of kinetic energy of the atoms or molecules.

Kelvin (K)

The SI unit of temperature, where $0\,K$ (absolute zero) is the coldest temperature possible ($-273.15\,^\circ\text{C}$).

Derived unit

A combination of other standard units, such as volume ($\text{cm}^3$) or density ($\text{mass/volume}$).

Density

The ratio of a substance’s mass to its volume.

Significant figures

Digits reported in a measurement such that every digit is certain except the last, which is estimated.

Scientific notation

A method of writing very large or small numbers using the format: (decimal point and sig. figs) $\times 10^{\text{multiplier}}$.

Exact numbers

Numbers with an unlimited number of significant figures, derived from accurate counting of objects, defined quantities, or integers in equations.

Accuracy

Refers to how close a measured value is to the actual value.

Precision

Refers to how close a series of measurements are to one another or how reproducible they are.

Dimensional analysis

The practice of using units as a guide to solving problems.

Unit equation

A statement showing two equivalent quantities, such as $1\,\text{in} = 2.54\,\text{cm}$.

Conversion factor

A fractional quantity used in dimensional analysis with the units converting from on the bottom and the units converting to on the top.