Chapter 1–2 Vocabulary Review

VOCABULARY flashcards covering key terms from Matter and Change and Measurements sections.

Matter

Anything that has mass and takes up space.

Mass

A measure of the amount of matter; measured with a balance.

Volume

The amount of three-dimensional space an object occupies.

Pure substance

A substance with a fixed composition that does not vary from sample to sample; can be an element or a compound.

Element

A pure substance that cannot be decomposed by chemical changes and is made of one kind of atom.

Compound

A substance that can be decomposed into simpler substances by chemical change; made from atoms of two or more elements bonded.

Molecule

The smallest unit of an element or compound that retains all the properties of that substance.

Mixture

A blend of two or more kinds of matter whose components retain their own identity.

Homogeneous mixture

A mixture with uniform composition; also called a solution.

Heterogeneous mixture

A mixture that is not uniform throughout; components remain distinct.

Physical property

A property observed or measured without changing the substance’s identity.

Chemical property

A property that describes a substance’s ability to undergo changes that produce new substances.

Physical change

A change that does not alter the identity of the substance.

Chemical change

A change in which substances are converted into different substances.

Intensive property

A property that does not depend on the amount of matter present.

Extensive property

A property that depends on the amount of matter present.

State of matter

The forms solid, liquid, and gas (and plasma as a high-temperature fourth state).

Melting point

The temperature at which a solid changes to a liquid.

Boiling point

The temperature at which a liquid changes to a gas.

Density

Mass per unit volume; defined as D = m/V; SI unit kg/m3, commonly g/cm3 or g/mL.

Atom

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

Element symbol

A one- or two-letter abbreviation for an element (e.g., H, Na).

Periodic table

An arrangement of elements in order of increasing atomic number with groups and periods that show patterns of properties.

Group (family)

A vertical column in the periodic table; elements with similar chemical properties.

Period

A horizontal row in the periodic table; properties change regularly across a period.

Metal

An element that is a good conductor of electricity and heat; typically shiny and malleable.

Nonmetal

An element that is a poor conductor of heat and electricity; often brittle.

Metalloid

An element with properties between metals and nonmetals; often a semiconductor.

Noble gas

An element in Group 18; generally unreactive and used in lighting.

Basic research

Research carried out to increase knowledge for its own sake.

Applied research

Research carried out to solve practical problems.

Technological development

Use of existing knowledge to create products and improve quality of life.

SI base units

The seven fundamental units used in science (meter, kilogram, second, kelvin, mole, ampere, candela).

Derived SI units

Units formed by combining base units (e.g., square meter, liter).

Mass vs weight

Mass is a measure of the amount of matter and is independent of gravity; weight is the gravitational force on matter.

Conversion factor

A ratio from an equality between two units used to convert from one unit to another.

Dimensional analysis

A method using units to solve problems and convert between units.

Scientific method

A systematic process of observing, hypothesizing, testing, and forming theories.

Hypothesis

A testable statement that makes predictions to be tested by experiments.

Theory

A broad generalization that explains a body of facts or phenomena and can predict outcomes.

Model

An explanation of how phenomena occur; may be visual, verbal, or mathematical.

Control

An aspect of an experiment kept constant to compare outcomes.

Variable

A condition that can change during an experiment.

Data

Descriptive or numerical information collected in an investigation.

System

A specific portion of matter chosen for study in an experiment.