alkanes Flashcards
What are Alkanes?
Alkanes are purified from crude oil and are important fuels.
Alkenes are produced when?
Alkenes are produced when long alkanes are ‘cracked’ - and because they are reactive, they are often used as the starting point for chemical reactions, such as making plastics.
Alkanes (saturated hydrocarbons)
A hydrocarbon is a compound which is made from carbon and hydrogen atoms only. One family of hydrocarbons is the alkanes.
In the alkanes, the carbon atoms are bonded to each other by single covalent bonds (C–C), so we say that the compounds are saturated.
Alkanes are saturated hydrocarbons. What is a hydrocarbon? What does saturated mean?
A hydrocarbon is a compound which is made from carbon and hydrogen atoms only. One family of hydrocarbons is the alkanes.
In the alkanes, the carbon atoms are bonded to each other by single covalent bonds (C–C), so we say that the compounds are saturated.
A hydrocarbon is a compound which is made from carbon and hydrogen atoms only. One family of hydrocarbons is the alkanes. In the alkanes, the carbon atoms are bonded to each other by single covalent bonds (C–C), so we say that the compounds are saturated.
Why are they are often used as the starting point for chemical reactions, such as making plastics?
Because they are reactive
What is the chemical formula for ethene?
ethene
C2H4
What is the chemical formula propene?
propene
C3H6
What is the chemical formula for butane?
butene
C4H8
What is the chemical formula for methane?
methane
CH4
Are Alkanes are relatively unreactive with aqueous reactants or reactive? Why?
relatively unreactive with aqueous reactants because the C–C and C–H bonds that they contain are strong and hard to break.
Alkanes tend to burn well in plenty of air to produce carbon dioxide and water. For example:
propane + oxygen → carbon dioxide + water
C3H8 + 5O2 → 3CO2 + 4H2O
From the balanced symbol equation, it can be seen that five oxygen molecules are needed for every propane molecule. Burning one propane molecule produces three carbon dioxide molecules and four water molecules.
What can be seen from thisbalanced symbol equation? propane + oxygen → carbon dioxide + water
C3H8 + 5O2 → 3CO2 + 4H2O
It can be seen that five oxygen molecules are needed for every propane molecule. Burning one propane molecule produces three carbon dioxide molecules and four water molecules
Alkenes are a family of ………………which contain…….. double bonds. why do we call them unsaturated molecules?
The displayed formulae of the first three alkenes are shown in the table below. Note the double bond between two of the carbon atoms.
Alkenes are a family of hydrocarbons which contain C=C double bonds. Because they contain C=C double bonds, we call them unsaturated.
Alkenes are more reactive or less reactice than alkanes, and they turn what sort of water colourless?
Alkenes are more reactive than alkanes, and they turn bromine water colourless
