4.5.2 - Alkanes Flashcards
What is an alkane !?
. Alkanes are hydrocarbons that fit the general formula
How do you name an alkane!?
. The start of the name shows how many carbon atoms it has.
. The end of the name is “-ane” to show it’s an alkane.
Names and diagrams of the binding in the first few alkanes:
What is the displayed formula (of butane) !?
. The displayed formula is a diagram showing the positions is every atom and every bond
What is the structural formula (of butane) !?
. This shows the structure of the molecule in one line read from left to right like a word.
What is the molecular formula (of butane) !?
. This only shows how many carbon and hydrogen atoms there are
What is the empirical formula (of butane) !?
. This only shows the simplest whole number ratio of carbon to hydrogen.
What is a homologous series !?
A family of molecules, which have:
.Similar chemical reactions
.Trends in physical properties, e.g. boiling points, viscosity, or colour
.The same general formula
What is an isomer?
Isomers of molecules with the same molecular formula, but different structural formulae
Equation for complete combustion of alkanes :
Alkane➕oxygen➡️carbon dioxide➕ - water
When does complete combustion of alkanes occur?
. When there is excess oxygen.
When does incomplete combustion of alkanes occur?
When there isn’t enough oxygen
What are the products of incomplete combustion of alkanes ?
. Carbon monoxide
. Soot
( releases less energy )
What three significant pollutants does the combustion of alkanes release into the atmosphere?
. Carbon dioxide (greenhouse gas)
. Nitrogen oxides (acid rain)
. Sulphur dioxide (acid rain)
How do alkanes react with halogens !?
. Alkanes react with halogens by swapping one hydrogen atom for one halogen atom.
Eg:
