WSC ‘25 another sci

What is oxidation?

The loss of electrons in an element or polyatomic ion during a chemical reaction, increasing its oxidation state.

What is an ionic bond?

A bond where one atom transfers one or more electrons to another.

What happens during oxidation?

An atom loses electrons.

What is reduction?

A chemical process where an element gains electrons, decreasing its oxidation state.

What is a redox reaction?

A chemical reaction that includes both reduction and oxidation.

Are all redox reactions ionic bonds?

Yes, but not all ionic bonds are redox reactions.

What is a real-life example of oxidation?

Rusting—Iron III reacts with oxygen and water to form iron oxide.

What is ignition?

The act of setting something on fire; also called firelighting or kindling.

When did humans first begin using fire?

During the Lower Paleolithic era.

What causes ignition?

A supply of energy in the form of heat, often through friction.

What is autoignition temperature?

The temperature at which a substance catches fire without an external spark or flame.

What happens to autoignition temperature when air pressure decreases?

It also decreases.

What is combustion?

A redox reaction between a fuel and an oxidant (usually oxygen), often producing heat.

Does combustion always produce fire?

No, not all combustion results in fire.

What happens during combustion of carbon/hydrogen?

They react with oxygen in an exothermic reaction.

What is activation energy?

The energy needed to start a combustion reaction.

What keeps a combustion reaction going?

A self-sustaining chain reaction of released energy.

What is complete combustion?

Combustion where there is enough oxygen to fully burn the fuel.

What is incomplete combustion?

Combustion where oxygen is the limiting reactant, so fuel doesn't burn completely.

What is pyrolysis?

The chemical separation of burnable and non-burnable parts of a fuel source before combustion.

What is flash point?

The lowest temperature at which a liquid produces flammable vapors that can ignite with a spark.

How is flash point different from autoignition temperature?

Flash point is lower and requires a spark; autoignition doesn't.

How do flash points differ between gasoline and diesel?

Gasoline has a lower flash point, making it easier to ignite.

Why are gasoline fumes dangerous at room temperature?

Gasoline's flash point is below room temp, so it emits flammable vapors.

What is convection?

The transfer of thermal energy through a fluid like air or water.

What causes natural convection?

Heat causes molecules to expand, rise, and collide, spreading energy.

What is forced convection?

External forces like fans or pumps spread heat.

What role does convection play in the atmosphere?

It causes phenomena like clouds and thunderstorms.

Why doesn't natural convection work in space?

Because it relies on gravity.

What is the fire triangle?

A model showing that heat, fuel, and oxygen are needed for fire.

How do you extinguish a fire by removing oxygen?

By smothering it or limiting oxygen access.

Why does water extinguish fire?

It prevents pyrolysis, stopping fuel from being consumed.

What is the fire tetrahedron?

An extension of the fire triangle that includes the chain reaction of combustion.

Why is the fire tetrahedron not a square?

Each element connects symbolically to all others and must be present.

What is a flame?

The visible part of a fire, usually red-orange, but color varies by heat and fuel.

What is a blue flame?

A very hot flame that may indicate complete combustion.

What is plasma in terms of flame?

Ionized gas formed at high enough temperatures, like in the Sun.

Why are flames spherical in space?

Without gravity, heat radiates evenly without convection.

What is fuel?

A material that releases energy when it reacts, typically with oxygen.

What are common fuels?

Coal, oil, gas, and hydrocarbons.

Why do fuels release more energy than they take in?

Because they store potential energy over time, often from photosynthesis.