The alkenes and their general formula, the C=C double bond, and what forms when hydrogen, steam or a halogen adds across it.
What you will learn
- Use CnH2n to name alkenes and give their formulae
- Predict the product of adding hydrogen, water or a halogen to an alkene
- Calculate the Mr and reacting masses of addition products
The alkenes
Alkenes are hydrocarbons with one C=C double bond.
They form a homologous series with the general formula:
alkenes: CnH2n
Ethene C2H4, propene C3H6, butene C4H8, pentene C5H10. There is no "methene": you need two carbons to make a double bond.
Alkenes burn like alkanes, but often with a smokier flame, because more of the carbon is left unburnt.
The rest of this lesson and its 11 practice questions are locked.
In this lesson
- The alkenes
- Addition reactions
- Try it: Name the product
- Masses in addition reactions
11 practice questions, marked as you go; about 22 minutes in all.
Key terms
One product, Hydrogenation, Hydration, Whole
In this unit: Organic chemistry
Crude oil and the alkanes, combustion and cracking, then alkenes, alcohols, carboxylic acids, esters and polymers for separate Chemistry, with the formula and mass calculations that go with them.