Chapter E Essentials: Units, Measurements, and Problem Solving

Vocabulary flashcards covering key terms from Chapter E: Essentials: Units, Measurements, and Problem Solving.

Qualitative observation

Descriptive, non-numeric observation about the qualities of a substance or situation.

Quantitative observation

Observation that involves numerical measurements obtained from instruments or devices.

Measurement

A quantity expressed as a numerical value with a unit; consists of a unit and a value.

SI (International System of Units)

Metric-based system of units used in science, including meter, kilogram, second, kelvin, and mole.

Unit

The dimensional part of a measurement (the quantity being measured), e.g., meter, kilogram.

Numerical value

The numeric part of a measurement that indicates magnitude, reflecting instrument precision.

Systematic error

Error that biases measurements in the same direction (bias in one direction).

Random error

Error that has equal probability of being higher or lower than the true value; unpredictable.

Meter (m)

SI base unit of length.

Kilogram (kg)

SI base unit of mass.

Second (s)

SI base unit of time.

Kelvin (K)

SI base unit of temperature; 0 K is absolute zero.

Mole (mol)

SI base unit of the amount of substance; 6.02×10^23 entities.

Liter (L)

Unit of volume commonly used outside SI; 1 L = 1000 cm^3.

Prefix

Multiplied attached to a unit (e.g., kilo-, centi-, milli-) to form larger or smaller units.

Significant figures

Digits used to express the precision of a measurement; determined by the measurement and equipment.

Leading zeros

Zeros to the left of the first nonzero digit; not significant.

Interior zeros

Zeros between nonzero digits; always significant.

Trailing zeros

Zeros to the right of a nonzero digit; significant only if a decimal point is present.

Scientific notation

Notation of numbers as a × 10^n with 1 ≤ a < 10; used for very large or small values.

Exact value

A defined or counted value treated as having infinite significant figures (e.g., conversion factors, defined constants).

Density

Mass per unit volume (density = mass/volume); an intensive property.

Intensive property

Property that does not depend on the amount of substance (e.g., density, temperature).

Extensive property

Property that depends on the amount of substance (e.g., mass, volume).

Dimensional analysis

Method of converting units by using conversion factors to cancel units.

Conversion factor

A ratio that expresses the same quantity in different units, used to convert between units.

Absolute zero

0 K, corresponding to −273 °C or −459 °F; the lowest possible temperature.

Celsius to Kelvin conversion

T(K) = t(°C) + 273.15.

Celsius to Fahrenheit conversion

F = 1.8(°C) + 32.

Train Track Method

Classroom technique for unit conversions using a sequence of conversion factors.

Precision

Closeness of a series of measurements to each other.

Accuracy

Closeness of a measurement to the true or accepted value.

Uncertainty

Doubt about the correctness of a measured value; associated with measurement.