Introduction to Chemistry and Measurement

Flashcards covering core concepts, classifications of matter, measurement rules, significant figures, and fundamental properties from lecture notes.

Chemistry

The study of matter, including its composition, properties, changes, and the energy associated with those changes.

Matter

Anything that has mass and occupies space.

Intensive property

A property that is independent of the amount of substance present, such as color, luster, melting and boiling points, hardness, and density.

Extensive property

A property that varies with the quantity of the substance present, such as volume and mass.

Physical Properties

Properties that matter has that do not require a change in the matter's composition, such as color, melting point, boiling point, and density.

Chemical Properties

Properties associated with matter undergoing a chemical change, such as flammability.

Physical Change

A change in which the chemical identity of matter is not changed.

Chemical Change

A change in which the chemical identity of matter is changed.

Law of Conservation of Mass

A principle discovered by Antoine Lavoisier stating that mass is neither created nor destroyed during a chemical change.

Pure substance

A class of matter made up of only one component with an invariant composition.

Mixture

A substance composed of two or more components in proportions that can vary from one sample to another.

Element

A pure substance that cannot be chemically broken down into simpler substances.

Compound

A substance composed of two or more elements in fixed definite proportions.

Heterogeneous mixture

A mixture in which the composition varies from one region to another.

Homogeneous mixture

A mixture made of multiple substances that appears to be one substance because its components mix uniformly.

Qualitative observation

An observation that is descriptive in nature.

Quantitative observation

An observation that involves measurements.

Measurement

A quantitative observation consisting of two parts: a number and a scale (unit).

Accuracy

The degree of agreement between a particular measurement and the true value.

Precision

The degree of agreement among several measurements of the same quantity.

Significant figures

The total number of digits in a measurement, including all certain digits and the first uncertain digit.

Leading zeros

Zeros that precede all nonzero digits and do not count as significant figures.

Captive zeros

Zeros between nonzero digits that always count as significant figures.

Trailing zeros

Zeros at the end of a number that are significant only if the number contains a decimal point.

Exact numbers

Numbers that arise by counting or definition and possess an infinite number of significant figures.

Absolute temperature scale

The Kelvin ($K$) scale, which begins at absolute zero ($0\,K$) and contains only positive values.

Density

An intensive property calculated as the mass of a substance divided by its volume ($d = \frac{m}{v}$).