Alkanes, Fractional Distillation, Cracking, and Combustion

Vocabulary flashcards covering alkanes, fractional distillation fractions, thermal and catalytic cracking, complete and incomplete combustion, and internal combustion engine pollutants and catalytic converters.

Petroleum

A mixture consisting mainly of alkanes.

Fractional Distillation

A separation process where crude oil is vaporized and passed through a fractionating tower that is hot at the bottom and cold at the top; vapor rises, cools, and molecules condense at different heights depending on their boiling points.

Fraction

A mixture of hydrocarbons with similar boiling points separated during fractional distillation.

Cracking

A process that breaks carbon-carbon bonds into smaller ones to produce molecules with greater economic value and demand.

Thermal Cracking

A cracking process requiring crude oil, higher temperature, and high pressure without a catalyst to produce alkenes, which are used to make polymers.

Catalytic Cracking

A cheaper cracking method using crude oil, high temperature, slight pressure, and a zeolite catalyst to produce branched alkanes (burn easier in petrol) and aromatics for petrol and diesel.

Zeolite Catalyst

The catalyst utilized in catalytic cracking to produce high proportions of branched alkanes and aromatic molecules.

Combustion

A rapid reaction between a substance and oxygen that releases heat and light energy.

Fuel

A substance that reacts with oxygen to release useful energy.

Complete Combustion

A reaction occurring when sufficient oxygen is present for all carbon atoms to burn, releasing heat with a large negative enthalpy of combustion: $\text{hydrocarbons} + \text{oxygen} \rightarrow \text{carbon dioxide} + \text{water}$.

Incomplete Combustion

A reaction occurring when there is not enough oxygen available for all carbon atoms to burn completely, forming carbon monoxide: $\text{hydrocarbons} + \text{oxygen} \rightarrow \text{carbon monoxide} + \text{water}$.

Carbon Particulates (Soot)

Solid carbon particles produced when hydrocarbon combustion occurs under very limited oxygen conditions: $\text{hydrocarbons} + \text{oxygen} \rightarrow \text{carbon} + \text{water}$.

Catalytic Converter

An exhaust device with a ceramic honeycomb structure coated in catalyst metals ($Pt$, $Pd$, $Rh$) that provides a large surface area to convert $CO$, $NO_x$, and unburnt hydrocarbons into $CO_2$, $N_2$, and $H_2O$.