Chapter 1: Matter and Energy - Vocabulary Flashcards

Vocabulary flashcards covering key terms and concepts from Chapter 1: Matter and Energy.

Matter

Anything that has mass and occupies space; composed of particles; its structure determines its properties.

Solid

A state of matter with fixed shape and fixed volume.

Liquid

A state of matter with fixed volume but no fixed shape.

Gas

A state of matter with no fixed shape and no fixed volume.

Atom

The smallest unit of an element that retains the chemical properties of that element; building block of matter.

Molecule

Two or more atoms bound together in a specific geometrical arrangement.

Element

A pure substance that cannot be decomposed by ordinary means; composed of a single type of atom; 118 confirmed elements.

Compound

A pure substance composed of two or more elements chemically bonded in fixed proportions.

Pure substance

A substance with a single composition that cannot be physically separated into simpler substances.

Diatomic elements

Elements that exist as diatomic molecules: H2, N2, O2, F2, Cl2, Br2, I2.

Mixture

A combination of two or more substances that are physically combined, not chemically bonded.

Homogeneous mixture

A mixture with uniform composition throughout (also called a solution).

Heterogeneous mixture

A mixture with non-uniform composition; components are distinguishable.

Physical property

A property observed without changing the substance’s composition (appearance, color, odor, melting point, density, etc.).

Chemical property

A property observed only via a chemical change that changes the substance’s composition (flammability, acidity, toxicity, etc.).

Physical change

A change that does not alter the substance’s chemical composition (e.g., phase changes, mixing).

Chemical change

A change that alters the substance’s composition; a chemical reaction occurs.

Scientific Method

A systematic process: observe, form a hypothesis, perform experiments (one variable at a time), and refine/repeat.

Scientific Law

A concise statement describing how natural phenomena behave; generally accepted as truth and not violated.

Scientific Theory

An explanation of a law based on experimental observations; explains why a phenomenon occurs; not proven beyond doubt.

Energy

The capacity to do work; work is the application of a force through a distance.

Kinetic Energy

Energy of motion; KE = 1/2 mv^2.

Potential Energy

Energy due to position or chemical composition; PE = mgh (gravity) among others.

Thermal Energy

Energy associated with the temperature of a system; arises from the motion of particles; a form of kinetic energy.

Temperature

Measure of the average kinetic energy of the particles in a substance.

SI Units

International System of Units: mass kg, length m, time s, amount of substance mol, temperature K, energy J.

Temperature Scales

Common scales include Celsius, Kelvin (SI unit), and Fahrenheit.

Kelvin Relation

To convert Celsius to Kelvin: K = °C + 273.15.

Metric Prefixes

Prefixes indicating powers of ten, e.g., Giga (G, 10^9), Mega (M, 10^6), Kilo (k, 10^3), Deci (d, 10^-1), Centi (c, 10^-2), Milli (m, 10^-3), Micro (µ, 10^-6), Nano (n, 10^-9).

Density

Density = mass/volume; units g/cm^3; an intensive property (independent of amount). Mass and volume are extensive properties.

Mass

A measure of the amount of matter in an object; an extensive property.

Volume

The amount of space that a substance occupies; used with density to relate mass and volume.

Significant Figures (sig figs)

Digits that carry meaning about precision; measurements have uncertainty.

Captive Zeros

Zeros between nonzero digits; significant.

Leading Zeros

Zeros to the left of the first nonzero digit; not significant.

Trailing Zeros

Zeros after a decimal point are always significant; before a decimal point are significant; without a decimal point significance is ambiguous.

Exact Numbers

Numbers with no uncertainty (counting numbers, defined quantities); infinite sig figs.

Addition/Subtraction Sig Fig Rule

Result has the same number of decimal places as the quantity with the fewest decimal places.

Multiplication/Division Sig Fig Rule

Result has the same number of sig figs as the factor with the fewest sig figs.

Rounding Rule

When rounding, look at the first digit dropped; 5 or more rounds up, 4 or less rounds down.

Dimensional Analysis

A problem-solving method using conversion factors to convert quantities and track units.

Conversion Factor

A ratio of equivalent quantities used to convert units (e.g., 1 in = 2.54 cm).

Scientific Notation

Expressing numbers as a × 10^n (e.g., 5.68 × 10^6).

Uncertainty in Experiments

Two kinds of numbers: exact (no uncertainty) and inexact (have uncertainty); experimental values have some uncertainty.