Energy and Its Forms: Practice Flashcards

These flashcards cover the key vocabulary for energy, its various forms, methods of heat transfer, measurement scales, and common energy concepts in chemistry and biology.

Energy

The ability to do work or produce heat.

Law of the conservation of energy

The law stating that energy can be neither created nor destroyed; it can only change form.

Kinetic energy

The energy of motion.

Potential energy

Stored energy that exists by virtue of an object's position or composition.

Mechanical energy

Kinetic energy that is doing mechanical work; the energy of an object in motion.

Electrical energy

The energy of a moving electrical charge in the form of charged particles (ions or electrons).

Conductor

A substance through which an electric current can pass, such as copper or aluminum.

Conductance

The measure of the ability to carry a current.

Thermal energy

The energy of the kinetic motion of molecules.

Radiant energy

Energy that travels through space in the form of electromagnetic waves.

Nuclear energy

The energy released in a nuclear reaction, such as during fission (splitting a nucleus) or fusion (combining nuclei).

Chemical energy

The potential energy that exists in bonds between atoms.

Photosynthesis

The endothermic chemical reaction that converts sunlight, carbon dioxide, and water into a carbohydrate, with an enthalpy change of $+2.80 \times 10^3\,kJ/mol$ glucose.

Respiration

The exothermic reaction by which a living being combines carbohydrates with oxygen to produce energy, carbon dioxide, and water.

Temperature

The measure of the kinetic motion of molecules, expressed in degrees of a scale.

Heat

Energy transferred from a system with higher thermal energy to a system with lower thermal energy.

Conduction

The transfer of energy through direct physical contact.

Radiation

Heat that flows between objects that are not in physical contact, such as the thermal energy transferred from the Sun to Earth.

Convection

The method of transferring energy through a secondary medium, such as a gas or liquid, that is in contact with the warmer and cooler systems.

Joule

The unit of measure for all types of energy, defined as the energy required to move a $1\,kg$ mass a distance of $1\,m$ at an acceleration of $1\,m/s^2$.

Celsius scale $(\text{°C})$

A temperature scale based on the points at which water changes phases: $0\,\text{°C}$ is the freezing point and $100\,\text{°C}$ is the boiling point.

Fahrenheit scale $(\text{°F})$

A temperature scale common in the United States where the freezing point of water is $32\,\text{°F}$ and the boiling point is $212\,\text{°F}$.

Kelvin scale $(K)$

A scientific temperature scale where $0$ is absolute zero, using the same incremental increase of thermal energy as the Celsius scale.

Absolute zero

The coldest temperature theoretically possible ($0\,K$, $-273.15\,\text{°C}$, or $-459.67\,\text{°F}$), at which all kinetic motion stops.

System

The parts of physical reality that compose the subject of analysis.

Surroundings

The parts of physical reality that are not defined as part of the system.

Calorimeter

A device made of low conducting materials that can approximate a closed system to measure heat exchanges.

calorie $(c)$

The amount of energy needed to raise the temperature of $1\,g$ of water $1\,\text{°C}$, equivalent to $4.18\,J$.

Calorie $(C)$

Also known as a Food Calorie or Nutritionist's Calorie; it is equivalent to $1000$ calories.

Specific heat

The amount of heat required to change the temperature of a given mass of a substance.

Heat equation

The formula to calculate energy change: $Q = mc\Delta T$, where $Q$ is heat, $m$ is mass, $c$ is specific heat, and $\Delta T$ is temperature change.

Enthalpy ($\Delta H$)

The net change in energy (absorbed or released) during a chemical reaction.

Geothermal energy

Energy derived from the earth's natural heat.