CHEMISTRY: Particles of Matter, Measurement and the Tools of Science

Flashcards covering key vocabulary, definitions, and concepts from the 'Particles of Matter: Measurement and the Tools of Science' lecture.

Chemistry

The study of the composition, structures, and properties of matter.

Matter

Anything that occupies space and has mass.

Mass

Defines the quantity of matter.

Energy

The capacity to do work.

Pure substance

Matter that has the same chemical and physical properties throughout and cannot be separated into simpler substances by a physical process.

Physical process

A transformation of a sample of matter that does not alter its chemical identity.

Element

A pure substance that cannot be separated into simpler substances by any chemical process.

Compound

A pure substance composed of two or more elements bonded together in fixed proportions, which can be broken down into individual elements by chemical reactions.

Mixture

A combination of two or more pure substances.

Homogeneous mixture

A mixture where components are distributed uniformly throughout the sample and have no visible boundaries or regions; also called a solution.

Solution

Another term for a homogeneous mixture.

Heterogeneous mixture

A mixture where components are not distributed uniformly and may have distinct regions of different composition.

Atom

The smallest particle of an element that retains the chemical characteristics of that element.

Molecule

An assembly of two or more atoms that are held together in a characteristic pattern by chemical bonds.

Chemical formula

A notation for representing elements and compounds, consisting of symbols of elements and subscripts identifying the number of atoms of each element in one molecule.

Chemical reaction

The transformation of one or more substances into different substances.

Chemical equations

Use chemical formulas to express the identities of substances and coefficients to indicate quantities involved in a reaction.

Law of Constant Composition

States that all samples of a particular compound contain the same elements combined in the same proportions.

Ions

Positively or negatively charged particles.

Cations

Positively charged ions.

Anions

Negatively charged ions.

Centrifugation

A process for separating particles by applying a centripetal force to allow sedimentation of a heterogeneous mixture.

Electrophoresis

A process for separating molecules based on their charge and size.

Filtration

A process for separating particles from a liquid or gas by passing the mixture through a medium that retains particles.

Distillation

A separation technique in which the more volatile components of a mixture are vaporized and then condensed, thereby separating them from less volatile components.

Intensive property

A property that is independent of the amount of substance present (e.g., color, density).

Extensive property

A property that varies with the quantity of the substance present (e.g., volume, mass).

Physical property

A property of a substance that can be observed without changing it into another substance (e.g., luster, melting point).

Chemical property

A property of a substance that can be observed only by reacting it to form another substance (e.g., flammability).

Density

The ratio of the mass of an object/substance to the volume of the object/substance (d = m/v).

Solid

A state of matter with definite shape and volume.

Liquid

A state of matter that occupies a definite volume but flows to assume the shape of its container.

Gas (vapor)

A state of matter with neither definite shape nor volume; it expands to fill its container.

State change

A transformation from one state of matter to another due to the addition or removal of heat.

Melting

The change of state from solid to liquid.

Freezing

The change of state from liquid to solid.

Vaporization

The change of state from liquid to gas.

Condensation

The change of state from gas to liquid.

Sublimation

The change of state directly from solid to gas.

Deposition

The change of state directly from gas to solid.

Scientific Method

A systematic approach to research that involves observation, hypothesis formation, experimentation, and theory establishment.

Hypothesis

A tentative and testable explanation for an observation or a series of observations.

Scientific theory

A general explanation of widely observed phenomena that has been extensively tested and validated.

SI Base Units

Fundamental units of measurement in the International System of Units, such as kilogram (mass), meter (length), kelvin (temperature), and second (time).

Unit conversion factor

A ratio of equivalent values used to convert a value from one unit to another.

Significant figures (Sig. Figs.)

All digits in a measurement known with certainty plus one digit that is uncertain.

Uncertain digit

The last estimated digit in a measured value.

Leading zeros

Zeros that precede all nonzero digits in a number; they are not significant.

Trailing zeros

Zeros at the end of a number; they are not significant unless they come after a decimal point.

Captive zeros

Zeros located between nonzero digits; they are always significant.

Accuracy

The agreement between a measured value and the accepted (true) value.

Precision

The agreement between repeated measurements of the same quantity.

Mean (x̅)

The sum of all individual values divided by the number of values (also known as the average).

Standard deviation (s)

A measure of the dispersion or spread of a set of data points around the mean.

Fahrenheit (°F)

A temperature scale where water freezes at 32°F and boils at 212°F.

Celsius (°C)

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

Kelvin (K)

The SI base unit of temperature; an absolute temperature scale where 0 K represents absolute zero.