Alkenes

Question 1

Alkenes

Answer 1

General Formula: CnH2n
Un/saturated compound: unsaturated (it reacts easily, contains a double carbon bond)
C=C: contains C=C
Reaction: Addition reaction

Question 2

Reaction of Alkenes with Bromine

Answer 2

Reaction: Addition reaction
Method: 1. Shake bromine with an alkene.
2. Check if bromine decolourises
immediately.

Question 3

Complete Combustion of Alkenes

Answer 3

There is a plentiful supply of oxygen.
Carbon dioxide and water are the products.

Question 4

Word and Symbol Equation

*For the complete combustion of alkenes.

Answer 4

methane + oxygen -> carbon dioxide and water
CH₄ + (4/)2O₂ -> CO₂ + 2H₂O
ethane + oxygen -> carbon dioxide and water
C₂H6 + 7/2O₂ -> 2CO₂ + 3H₂O
Of the products, the amount of CO₂ is equal to the amount of carbons in methane (1). The O₂ is just the amount of CO₂ + 1.

Question 5

Incomplete Combustion of Alkenes

Answer 5

There is an insufficient/ limited supply of oxygen.
The products are carbon monoxide (CO)/ carbon (C) and water.

Question 6

Word and Symbol Equation

*For the incomplete combustion of alkenes.

Answer 6

methene + oxygen -> carbon monoxide and water
CH2 + 3/2O₂ -> CO + 2H₂O
ethene + oxygen -> carbon dioxide and water
C₂H4 + 2O₂ -> 2CO + 2H₂O
Of the products, the amount of CO is equal to the amount of carbons in methane (1), the same for the O₂. Of the O₂ in the reactants, it is the amount of H₂ in the hydrocarbon - 2.