Chapter 1: The Science of Change — Key Vocabulary

A vocabulary set covering foundational concepts from Chapter 1: The Science of Change, focusing on matter, measurement, SI units, and basic properties of matter.

Matter

Anything that has mass and occupies space.

Chemistry

The study of matter and the changes that matter undergoes.

Scientific Method

Guidelines: gather data via observations and experiments; identify patterns; summarize findings with a law; formulate a hypothesis; a hypothesis may evolve into a theory.

SI Base Units

Seven base units used in the SI system to define all other units (meter, kilogram, second, ampere, kelvin, mole, candela).

Meter

SI base unit of length; symbol m.

Kilogram

SI base unit of mass; symbol kg.

Second

SI base unit of time; symbol s.

Ampere

SI base unit of electric current; symbol A.

Kelvin

SI base unit of temperature; symbol K.

Mole

SI base unit of amount of substance; symbol mol.

Candela

SI base unit of luminous intensity; symbol cd.

Prefix

A multiplier that alters the magnitude of a unit (e.g., kilo-, milli-, micro-).

Volume

Derived quantity for how much space a substance occupies; SI unit is cubic meter (m^3); practical unit is liter (L); 1 L = 1 dm^3; 1 mL = 1 cm^3.

Liter (L)

Practical unit of volume; 1 L = 1000 cm^3.

Cubic centimeter

Volume unit equal to 1 mL; 1 cm^3 = 1 mL.

Density

Mass per unit volume; d = m/V; SI unit kg/m^3; common units include g/cm^3, g/mL, g/L.

Atomic Mass Unit (amu)

Unit used to express masses of atoms; 1 amu = 1.6605378 \times 10^{-24} g.

Celsius

Temperature scale where water freezes at 0°C and boils at 100°C.

Fahrenheit

US temperature scale; water freezes at 32°F and boils at 212°F.

Celsius to Fahrenheit Conversion

Formula for converting Celsius to Fahrenheit: °F = (9/5) \times °C + 32

Fahrenheit to Celsius Conversion

Formula for converting Fahrenheit to Celsius: °C = (5/9) \times (°F - 32), or °C = \frac{°F - 32}{1.8}

Celsius to Kelvin Conversion

Formula for converting Celsius to Kelvin: K = °C + 273.15

Kelvin to Celsius Conversion

Formula for converting Kelvin to Celsius: °C = K - 273.15

Substance

Matter with definite composition and distinct properties.

Mixture

Physical combination of two or more substances; can be separated by physical means.

Homogeneous

Mixture uniform in composition throughout (also called a solution).

Heterogeneous

Mixture not uniform throughout.

Physical Property

Observable or measurable property that does not change the identity of the substance (e.g., color, melting point, boiling point).

Chemical Property

Property describing how a substance interacts with other substances (e.g., flammability, reactivity).