Keys to the Study of Chemistry - Vocabulary Flashcards

Vocabulary flashcards covering core concepts, properties, state changes, energy, scientific method, and measurement uncertainty from Chapter 1.

Chemistry

The study of matter, its properties, the changes that matter undergoes, and the energy associated with these changes.

Matter

Anything that has both mass and volume; the "stuff" of the universe.

Properties

The characteristics that give each substance a unique identity.

Physical Properties

Properties a substance shows by itself without interacting with another substance, such as color, melting point, boiling point, and density.

Chemical Properties

Properties a substance shows as it interacts with, or transforms into, other substances, such as flammability and corrosiveness.

Physical Change vs. Chemical Change

A physical change alters physical form without changing composition because particles remain the same; a chemical change alters composition by decomposing or converting substances into different ones.

Solid

A state of matter that has a fixed shape and volume, which may be hard or soft, rigid or flexible.

Liquid

A state of matter that has a varying shape that conforms to its container, a fixed volume, and an upper surface.

Gas

A state of matter that has no fixed shape or volume and therefore does not have a surface.

Physical States of Matter

The three physical states characterized by particle spacing and arrangement: solids (close together and organized), liquids (close together but disorganized), and gases (far apart and disorganized).

Energy

The ability to do work.

Potential Energy

Energy due to the position of an object.

Kinetic Energy

Energy due to the movement of an object.

Law of Conservation of Energy

A principle stating that energy is neither created nor destroyed—it is conserved—and can be converted from one form to another.

Observation

Natural phenomena and measured events that can be stated as a natural law if universally consistent.

Hypothesis

A tentative proposal that explains observations.

Experiment

A procedure to test a hypothesis that measures one variable at a time.

Model (Theory)

A set of conceptual assumptions that explains data from accumulated experiments and predicts related phenomena.

Conversion Factor

A ratio of equivalent quantities used to express a quantity in different units.

Density

A characteristic physical property at a given temperature and pressure defined as mass divided by volume ($\text{density} = \frac{\text{mass}}{\text{volume}}$).

Kelvin (K) Scale

The absolute temperature scale that begins at absolute zero ($0\,\text{K}$) and has only positive values, using the same degree size as the Celsius scale without degree signs.

Celsius Scale

A temperature scale based on the freezing point ($0\,^\circ\text{C}$) and boiling point ($100\,^\circ\text{C}$) of water.

Fahrenheit Scale

A temperature scale commonly used in the US with different degree sizes and zero points, where water freezes at $32\,^\circ\text{F}$ and boils at $212\,^\circ\text{F}$.

Temperature Scale Comparison

The comparison of freezing and boiling points of water across Celsius ($0\,^\circ\text{C}$, $100\,^\circ\text{C}$), Kelvin ($273.15\,\text{K}$, $373.15\,\text{K}$), and Fahrenheit ($32\,^\circ\text{F}$, $212\,^\circ\text{F}$) scales.

Significant Figures

The recorded digits in a measurement, both certain and estimated, where a greater number of significant figures reflects greater certainty.

Measurement Certainty in Significant Figures

A measurement known with more decimal places (e.g., $32.33\,^\circ\text{C}$ vs. $32.3\,^\circ\text{C}$) has higher certainty because it contains more significant figures.

Exact Numbers

Numbers with no uncertainty associated with them, obtained by definition or counting, which do not limit the number of significant digits in calculations.

Precision

Refers to how close the measurements in a series are to each other.

Accuracy

Refers to how close each measurement is to the actual value.

Systematic Error

An error inherent to the experimental system that produces values that are either all higher or all lower than the actual value.

Random Error

An error that produces measurement values both higher and lower than the actual value.