Energy, Heat Transfer, Combustion, and Entropy

Vocabulary flashcards covering key concepts from energy, heat transfer mechanisms, combustion, and entropy as presented in the video notes.

Energy

The capacity to do work; energy can be transformed between forms but is conserved.

Kinetic Energy

Energy of motion; KE = 0.5 m(kg)v(m/s)².

Potential Energy

Stored energy due to position or state; includes gravitational and chemical potential energy.

Gravitational Potential Energy

Potential energy due to height in a gravitational field; GPE = m(kg)g(9.8m/s²)h(m).

Chemical Potential Energy

Energy stored in chemical bonds that can be released or absorbed during chemical reactions.

Conservation of Energy

Energy cannot be created or destroyed; it is transformed from one form to another.

Heat

Transfer of thermal energy between objects due to a temperature difference (Q = joules).

Temperature

A measure of the average kinetic energy of the particles in a substance.

Thermal Energy

Total kinetic energy of the particles in a substance; depends on mass, temperature, and specific heat capacity.

Specific Heat Capacity

Amount of energy required to raise the temperature of a substance per unit mass by 1°C (joules/gram°celsius).

Joules

Unit of energy and heat in the SI system.

Calorie

Unit of energy; traditionally the amount of heat required to raise 1 g of water by 1°C.

Kilocalorie

Unit equal to 1000 calories; commonly used to express food energy.

Conduction

Transfer of heat through direct contact; efficient in solids, especially metals; involves particle vibration and collision.

Thermal Conductivity

Material's ability to conduct heat; high k means a good conductor, low k means an insulator (watts/meterKelvin).

Convection

Transfer of heat by the movement of fluids (liquids or gases) due to density changes from heating.

Convection Currents

Circulation patterns created as heated fluid rises and cooler fluid sinks.

Thermal Boundary Layer

Thin layer of fluid near a surface where heat transfer is primarily by conduction.

Radiation

Transfer of heat through electromagnetic waves; can occur in a vacuum; intensity increases with temperature.

Electromagnetic Radiation

Heat transfer via electromagnetic waves such as infrared radiation.

Combustion

Rapid chemical reaction with an oxidant usually oxygen that releases heat and light.

Fire Triangle

Fuel, Oxidant, and Heat; all three are needed for combustion.

Fuel

Substance that burns in a combustion reaction.

Oxidant

Oxidizing agent, usually oxygen from the air.

Activation Energy

Minimum energy required to start and sustain a chemical reaction.

Exothermic Reaction

Reaction that releases energy mainly as heat and light.

Energy Transformation in Combustion

Chemical potential energy stored in fuel is converted into thermal energy and light energy.

Thermal Equilibrium

State where there is no net heat flow between objects in thermal contact; temperatures are equal.

Entropy

Measure of disorder or randomness in a system; tends to increase in an isolated system.

Second Law of Thermodynamics

In an isolated system, total entropy tends to increase over time.

Relevance to Combustion

Combustion releases energy and increases the entropy of the surroundings.