Chemistry Measurements & Data Vocabulary

A comprehensive set of vocabulary flashcards covering units and measurements, scientific notation, dimensional analysis, uncertainty in data, and graphing concepts from the lecture notes.

Système Internationale d'Unités (SI)

The internationally agreed-upon metric system used by scientists for all measurements.

Base unit

A fundamental SI unit defined by a physical object or event and independent of other units.

Second (s)

The SI base unit of time, defined by the radiation frequency of a cesium-133 atom.

Meter (m)

The SI base unit of length, equal to the distance light travels in vacuum in 1⁄299,792,458 of a second.

Kilogram (kg)

The SI base unit of mass; roughly equal to 2.2 pounds.

Kelvin (K)

The SI base unit of temperature.

Absolute zero

0 K, the point at which particle motion and kinetic energy are minimal.

SI prefix

A word part (kilo-, milli-, etc.) added to a base unit to indicate a multiple or fraction of that unit.

Derived unit

A unit formed by combining SI base units, such as m/s or g/cm³.

Liter (L)

A volume unit equal to one cubic decimeter (1 dm³).

Volume

The amount of space an object occupies; SI derived unit is the cubic meter (m³).

Density

Mass per unit volume; commonly expressed in g/cm³ and calculated as mass ÷ volume.

Cubic centimeter (cm³)

The volume of a cube 1 cm on each side; equivalent to 1 mL.

Gram per milliliter (g/mL)

A frequently used density unit for liquids and solids.

Scientific notation

A way to express numbers as a coefficient between 1 and 10 multiplied by 10 raised to a power.

Coefficient (scientific notation)

The number between 1 and 10 in scientific notation.

Exponent (scientific notation)

The power of ten indicating how many places the decimal point has moved.

Dimensional analysis

A systematic method that uses conversion factors to change one unit into another.

Conversion factor

A ratio of equivalent quantities with different units, equal to 1, used to convert measurements.

Quantitative data

Numeric information that describes how much, how little, how big, or how fast.

Accuracy

How close a measurement is to the accepted or true value.

Precision

How close a series of measurements are to one another.

Error

The difference between an experimental value and the accepted value.

Percent error

Error expressed as a percentage of the accepted value: |error| ÷ accepted value × 100%.

Significant figure

All known digits in a measurement plus one estimated digit, indicating measurement precision.

Placeholder zero

A zero used only to position the decimal point; not counted as significant.

Independent variable

The variable deliberately changed in an experiment; plotted on the x-axis of a graph.

Dependent variable

The variable that responds to changes in the independent variable; plotted on the y-axis.

Graph

A visual display of data that makes trends easier to observe than in a table.

Circle graph (pie chart)

A graph in which wedges represent percentages of a fixed whole.

Bar graph

A graph that uses bars to show how a quantity varies across categories.

Line graph

A graph that shows the relationship between two variables with points connected by a line.

Linear relationship

A straight-line relationship between two variables that can be analyzed by its slope.

Slope

On a line graph, the ratio of vertical change to horizontal change; indicates rate of change.

Interpolation

Estimating a value that falls between two measured points on a graph.

Extrapolation

Predicting a value outside the measured range by extending a graph’s trend line.

Système Internationale d'Unités (SI)

Internationally agreed-upon metric system used by scientists.

Base unit

A fundamental SI unit, independent of other units.

Second (s)

The SI base unit of time, defined by the radiation frequency of a cesium-133 atom.

Meter (m)

The SI base unit of length, defined by the distance light travels in vacuum in 1/299,792,458 of a second.

Kilogram (kg)

The SI base unit of mass (\approx 2.2 pounds).

Kelvin (K)

The SI base unit of temperature.

Absolute zero

0 K, the point of minimal particle motion and kinetic energy.

SI prefix

A word part added to a base unit to show multiples or fractions (e.g., kilo-, milli-).

Derived unit

A unit formed by combining SI base units (e.g., m/s, g/cm³).

Liter (L)

A volume unit equal to 1 cubic decimeter (1 \text{ dm}^3).

Volume

The amount of space an object occupies; SI derived unit is the cubic meter ( ext{m}^3).

Density

Mass per unit volume (mass \div volume), commonly in g/cm³ or g/mL.

Cubic centimeter (cm³)

The volume of a 1 \text{ cm} cube; equivalent to 1 \text{ mL}.

Gram per milliliter (g/mL)

A common density unit for liquids and solids.

Scientific notation

Expressing numbers as a coefficient (1-10) multiplied by 10 raised to a power.

Coefficient (scientific notation)

The number (1-10) in scientific notation.

Exponent (scientific notation)

The power of ten showing decimal point movement.

Dimensional analysis

A method using conversion factors to change units.

Conversion factor

A ratio of equivalent quantities with different units, equal to 1.

Quantitative data

Numeric information answering how much, how big, etc.

Accuracy

How close a measurement is to the true value.

Precision

How close a series of measurements are to each other.

Error

The difference between an experimental and accepted value.

Percent error

Error as a percentage of the accepted value: \frac{| \text{error} |}{ \text{accepted value}} \times 100\%

Significant figure

All known digits in a measurement plus one estimated digit, showing precision.

Placeholder zero

A zero used only to position the decimal point; not significant.

Independent variable

The variable changed in an experiment; plotted on the x-axis.

Dependent variable

The variable that responds to changes in the independent variable; plotted on the y-axis.

Graph

A visual display of data showing trends.

Circle graph (pie chart)

A graph where wedges represent percentages of a whole.

Bar graph

A graph that uses bars to show how a quantity varies across categories.

Line graph

A graph that shows the relationship between two variables with connected points.

Linear relationship

A straight-line relationship between two variables, analyzed by slope.

Slope

On a line graph, the ratio of vertical to horizontal change; indicates rate.

Interpolation

Estimating a value between two measured points on a graph.

Extrapolation

Predicting a value outside the measured range by extending a graph’s trend line.