Key Chemical Reactions and Definitions: Chapter 8

Addition reaction

When two molecules join to form one larger molecule (common with alkenes).

Combustion

A chemical reaction where a substance reacts with oxygen, releasing heat and light.

Complete combustion

Burning a fuel with enough oxygen to produce only carbon dioxide and water.

Incomplete combustion

Burning a fuel with limited oxygen, producing carbon monoxide or carbon (soot) alongside water.

Substitution reaction

A reaction where one atom or group in a molecule is replaced by another atom or group.

Crude oil

A natural, unrefined mixture of hydrocarbons extracted from the Earth.

Plant-sourced biomass

Organic material from plants used for fuel or chemical production.

Bioethanol

Ethanol (alcohol) produced from plant biomass (e.g., sugarcane or corn).

Bio-derived

Made from biological (natural, living) sources rather than fossil fuels.

Non-renewable

A resource that cannot be replaced within a human lifetime (e.g., fossil fuels).

Renewable

A resource that can naturally replenish over a short time (e.g., plants, solar energy).

Organic compound

A compound mainly made of carbon and hydrogen (and sometimes oxygen, nitrogen, etc.).

Alkane

A saturated hydrocarbon (single bonds only, e.g., methane).

Alkene

An unsaturated hydrocarbon with at least one double bond (e.g., ethene).

Haloalkane

An alkane with at least one hydrogen replaced by a halogen (e.g., chloromethane).

Alcohol

An organic compound with a hydroxyl (-OH) group attached to a carbon atom.

Carboxylic acid

An organic compound with a carboxyl group (-COOH).

Homologous series

A family of compounds with the same functional group and a pattern in structure and properties.

Functional group

The part of a molecule that largely controls how it reacts (e.g., -OH, -COOH, =C=).

Alkyl group

A group made by removing one hydrogen from an alkane (e.g., methyl -CH₃).

Alkyl side chain (branch)

An alkyl group attached to the main carbon chain as a side branch.

Halogen

A group 17 element (fluorine, chlorine, bromine, iodine) often found in haloalkanes.

Carboxyl group

The -COOH group in carboxylic acids.

Carboxylate ion

The ion formed when a carboxylic acid loses a hydrogen ion (H⁺), resulting in -COO⁻.

Hydroxyl group

The -OH group found in alcohols.

Molecular formula

Shows the number and type of atoms in a molecule (e.g., C₂H₆O).

Structural formula

Shows how atoms are connected in a molecule.

Semi-structural formula

Partially shows structure (e.g., CH₃CH₂OH for ethanol).

Condensed structural formula

A compact way of writing the structural formula (like semi-structural).

General formula

A formula that represents all members of a homologous series (e.g., alkanes: CₙH₂ₙ₊₂).

Structural isomer

Molecules with the same molecular formula but different arrangements of atoms.

Stem name

The base part of the name, based on the number of carbons in the longest chain (e.g., "meth-", "eth-", "prop-").

Locant

A number used to show the position of a group or double bond on the carbon chain.

Terminal carbon

A carbon atom at the end of a chain.

Physical property

A characteristic that can be observed without changing the chemical identity (e.g., melting point, boiling point).

Chemical property

How a substance reacts with other chemicals (e.g., flammability, acidity).

Melting point

The temperature at which a solid turns into a liquid.

Boiling point

The temperature at which a liquid turns into a gas.

Saturated

A molecule containing the greatest possible number of hydrogen atoms, without carbon–carbon double or triple bonds.

Unsaturated

A molecule with one or more double or triple bonds between carbon atoms.

Weak acid

An acid that only partially ionizes in water (e.g., carboxylic acids).

Photosynthesis

The process by which green plants use sunlight to make glucose and oxygen from carbon dioxide and water.

Polymer

A large molecule made from many smaller units (monomers) linked together.

Dimer

A molecule formed from two identical (or very similar) smaller units (monomers).

Fractional distillation

A process used to separate mixtures (like crude oil) based on different boiling points.

Hydrocarbon

A compound made only of hydrogen and carbon atoms.

Complete Combustion Reaction equation

hydrocarbon + oxygen → carbon dioxide + water

Incomplete Combustion Reaction equation

Hydrocarbon + limited oxygen → carbon monoxide + carbon + water