Organic Chemistry: an interactive introduction

Organic Chemistry is an interactive organic chemistry course that introduces the chemistry of carbon compounds. Its 23 short sections cover why carbon makes four bonds, four ways to draw a molecule, alkanes and their boiling points, alkenes and the bromine water test, functional groups, naming compounds step by step, structural isomers, combustion and addition polymers.

It opens with an alkane chain growing one CH₂ unit at a time from methane to octane, with its formula, mass and boiling point plotted as it grows: the idea of a homologous series in one demo.

What the course covers

Carbon and formulas

A carbon atom has four outer electrons and shares each one, so it always makes four bonds and can build chains, branches and rings. The course shows four ways to write the same molecule, from the molecular formula to the skeletal formula, where every corner and line end is a carbon and the hydrogens are left out.

Families of compounds

Alkanes have only single bonds and are saturated; alkenes have a C=C double bond, which turns orange bromine water colourless. A functional group, such as the OH of an alcohol or the COOH of a carboxylic acid, decides how a molecule reacts, and each family has its own name ending: ane, ene, ol or oic acid.

Isomers, burning and polymers

Structural isomers have the same molecular formula with atoms joined in a different order. With plenty of oxygen, a burning hydrocarbon gives carbon dioxide and water, and alkenes can join through their double bonds to make addition polymers such as poly(ethene).

Try a question from the course

Alkanes follow one general formula, CₙH₂ₙ₊₂: for n carbons there are 2n + 2 hydrogens. Hexane has 6 carbons, so it has 2 × 6 + 2 = 14 hydrogens: C₆H₁₄. An alkane with 10 carbons, decane, is C₁₀H₂₂.

Now write the formula of a new alkane, then press Mark to check your answer in the course.

Who this course is for

• GCSE chemistry students revising hydrocarbons, alkenes, alcohols, carboxylic acids and polymers.
• Students starting A-level chemistry who want naming, skeletal formulas and isomers on a firm footing.
• Anyone curious about the chemistry behind fuels and plastics.

What you need to know first

The course page suggests Chemical Bonding first: organic molecules are held together by covalent bonds, and boiling points depend on the forces between molecules. Balancing equations helps for the combustion section.

How long it takes

There are 23 sections and most take a few minutes. Learners without a plan can open two sections of a course a day, in order, so the whole course takes 12 days. A plan removes the daily limit and lets you go straight to any topic, such as naming or isomers.

Read next

Chemistry · Organic chemistryWhat is a homologous series? Definition and examplesA homologous series is a family of organic compounds sharing one general formula and functional group. Its features, with alkanes and alkenes as examples.