Units, Measurement, and Problem Solving

Vocabulary flashcards covering key terms from Chapter E on measurement units, SI base units, temperature scales, derived units, uncertainty, significant figures, energy, and dimensional analysis.

Units

Fixed, agreed-upon quantities to which other quantities are compared.

International System of Units (SI Units)

A standardized system of units based on the metric system, used by scientists worldwide to minimize confusion, consisting of seven base units and prefix multipliers.

Meter (m)

The SI base unit of length, defined as the distance that light travels in a vacuum in $1/299{,}792{,}458$ seconds.

Kilogram (kg)

The SI base unit of mass, representing the quantity of matter in an object ($1\,\text{kg} = 2.2\,\text{lb}$).

Mass

The quantity of matter contained within an object, which remains constant regardless of location or gravity.

Weight

A measure of the force exerted on an object by gravitational pull.

Second (s)

The SI base unit of time, defined scientifically using an atomic standard based on a cesium clock.

Temperature

A measure of the average kinetic energy of the particles in a sample of matter.

Celsius Scale

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

Kelvin Scale

The SI base unit scale of temperature, based on the properties of gases, which has no negative values and is calculated as $K = ^\circ\text{C} + 273.15$.

Derived Units

Measured properties that use a combination of SI base units, such as speed ($\text{m/s}$), volume ($\text{m}^3$), or density ($\text{g/cm}^3$).

Liter (L)

A metric unit of volume defined as the volume of a cube that is $1\,\text{decimeter}\ (1\,\text{dm})$ long on each side, equal to $1\,\text{dm}^3$.

Milliliter (mL)

A metric unit of volume defined as the volume of a cube that is $1\,\text{centimeter}\ (1\,\text{cm})$ long on each side, equal to $1\,\text{cm}^3$.

Volumetric Laboratory Equipment

Laboratory devices used to measure or transfer liquid volumes, including graduated cylinders, syringes, and burets for variable volumes, pipets for specific delivered volumes, and volumetric flasks for specific contained volumes.

Density

A derived quantity representing the mass of a substance per unit volume, expressed by the formula $d = \frac{m}{V}$.

Exact Numbers

Values known with complete certainty, such as counted quantities or defined conversion factors.

Inexact Numbers

Values obtained from measurement that contain a degree of uncertainty.

Accuracy

The proximity or closeness of a measurement to the true or accepted value of a quantity.

Precision

The proximity or agreement of several measurements of the same quantity to each other.

Significant Figures

Digits in a measured quantity that are measured and non-place holding, representing the precision of the measurement.

Energy

The capacity to do work.

Work

The action of a force applied across a distance.

Force

A push or pull exerted on an object.

Electrostatic Force

The push or pull exerted between objects that possess an electrical charge.

Potential Energy (PE)

Energy associated with the position or chemical composition of an object or system.

Kinetic Energy (KE)

Energy associated with the motion of an object, calculated using the equation $\text{KE} = \frac{1}{2} m v^2$.

Joule (J)

The SI unit of energy, equivalent to $1\,\text{kg}\cdot\text{m}^2/\text{s}^2$.

Calorie (cal)

A non-SI unit of energy defined as $1\,\text{cal} = 4.184\,\text{J}$.

Nutritional Calorie (Cal)

A unit of energy used in nutrition, equivalent to $1000\,\text{cal}$ or $1\,\text{kcal}$.

Law of Conservation of Energy

A fundamental law stating that energy can be neither created nor destroyed, only transferred or converted from one form to another.

System

The specific part of the universe selected as the point of interest for study or measurement.

Surroundings

Everything else in the universe outside of the defined system.

Exothermic Process

A process in which heat energy is released by the system to the surroundings ($\Delta H < 0$).

Endothermic Process

A process in which heat energy is absorbed by the system from the surroundings ($\Delta H > 0$).

Dimensional Analysis

A problem-solving approach that uses conversion factors (relationships between units) to convert one physical quantity to another.