Unit 1 Test Review: Matter, Measurements, and Significant Figures

Flashcards covering fundamental chemistry concepts including classification of matter, physical and chemical changes, SI units, accuracy, precision, and significant figure rules.

Matter

Anything that has mass, takes up space, and can exist as a solid, liquid, gas, or plasma, excluding light and energy.

Solid

A state of matter that has a definite shape and a definite volume.

Liquid

A state of matter that has a definite volume but no definite shape.

Gas

A state of matter that has neither a definite shape nor a definite volume.

Physical Properties

Properties of matter that can be directly measured or observed, categorized as either extensive or intensive.

Extensive Property

A physical property that depends on the size of the sample.

Intensive Property

A physical property that does not depend on the size of the sample.

Physical Change

A change that does not alter what the actual substance is.

Chemical Change

A change that produces new substances with their own unique properties, accompanied by signs such as color change, temperature change, or formation of a new phase (bubbles or precipitate).

Chemical Properties

Characteristics describing reactivity that are determined by a chemical reaction.

Mass

The amount of something you have.

Weight

The pull of gravity on a mass.

Law of Conservation of Matter

The principle stating that matter is neither created nor destroyed, but only changes form.

Substance

A general term for any pure element or compound.

Element

A substance that cannot be broken down into any other substance.

Atom

The smallest unit of matter that retains the properties of that element.

Compound

A substance made of $2$ or more elements chemically combined in a specific ratio or formula, possessing its own unique properties.

Molecule / Formula Unit

The smallest unit of matter that retains the properties of a compound.

Mixture

A physical combination of $2$ or more substances in any ratio in which each substance keeps its own properties.

Heterogeneous Mixture

A mixture that varies in composition throughout the sample.

Homogeneous Mixture

A mixture that has the exact same composition everywhere in the sample.

SI Base Units

The standard set of base units comprising length (meter, $m$), mass (kilogram, $kg$), temperature (kelvin, $K$), time (second, $s$), amount of substance (mole, $mol$), electric current (ampere, $A$), and luminous intensity (candela, $cd$).

Precision

The reproducibility of a measurement.

Accuracy

How close a measurement is to its true value.

Uncertainty in Measurements

The practice of reporting all certain digits plus one uncertain digit, corresponding to one place past the smallest division on the measuring device.

Significant Figures Rules

Guidelines stating that non-zero digits, trapped zeros, and trailing zeros after a decimal are significant; leading zeros and trailing zeros without a decimal are not; and counted numbers have an infinite number of significant figures.

Addition and Subtraction Rule for Significant Figures

The rule requiring the calculated answer to be rounded to the first decimal place that contains an uncertain digit.

Multiplication and Division Rule for Significant Figures

The rule requiring the calculated answer to be rounded to have the same number of significant figures as the multiplier with the fewest significant figures.