Hydrocarbons Flashcards
What is a hydrocarbon?
A hydrocarbon is an organic compound consisting entirely of carbon and hydrogen atoms.
What distinguishes alkanes from alkenes and alkynes?
Alkanes are saturated (only single bonds), alkenes contain at least one double bond, and alkynes contain at least one triple bond.
What is the general formula for alkanes?
CₙH₂ₙ₊₂.
What is the general formula for alkenes?
CₙH₂ₙ.
What is the general formula for alkynes?
CₙH₂ₙ₋₂.
What is meant by isomerism in hydrocarbons?
Isomerism in hydrocarbons occurs when compounds with the same molecular formula have different arrangements of their atoms.
Explain the difference between straight-chain and branched hydrocarbons.
Straight-chain hydrocarbons have carbon atoms arranged in a continuous line, while branched hydrocarbons have one or more carbon chains attached to the main chain.
What are some typical physical properties of alkanes?
They are generally non-polar, have low boiling points, and are insoluble in water.
Describe the combustion reaction of an alkane.
Combustion of an alkane with oxygen produces carbon dioxide, water, and releases energy (heat).
How do alkenes differ in reactivity compared to alkanes?
Alkenes are more reactive due to the presence of a carbon–carbon double bond, which is more chemically active than single bonds.
What is polymerization in the context of alkenes?
Polymerization is a reaction in which many small alkene molecules (monomers) join together to form a large polymer chain.
How do catalysts affect reactions involving hydrocarbons?
Catalysts lower the activation energy, making reactions like cracking and polymerization more efficient.
What is cracking in the petroleum industry?
Cracking is a process that breaks larger hydrocarbon molecules into smaller, more useful ones such as gasoline.
Why are hydrocarbons important for energy production?
Hydrocarbons are the primary constituents of fossil fuels, which, when combusted, release energy for power generation and transportation.
How are hydrocarbons separated using fractional distillation?
Fractional distillation separates hydrocarbons based on their boiling points, allowing different fractions (e.g., gasoline, diesel) to be collected.
What is aromaticity, and how does it relate to hydrocarbons?
Aromaticity is a property of cyclic, conjugated hydrocarbons (like benzene) that exhibit enhanced stability due to electron delocalization.
Describe the structure of benzene.
Benzene is a cyclic hydrocarbon with six carbon atoms forming a ring with alternating double bonds, which are best described as delocalized electrons over the ring.
What is the significance of delocalized electrons in aromatic hydrocarbons?
Delocalized electrons in aromatic systems provide extra stability and influence the compound’s chemical reactivity.
How do reaction conditions affect hydrocarbon reactions?
Factors such as temperature, pressure, and the presence of catalysts can significantly alter the reactivity and product distribution in hydrocarbon reactions.
List some everyday applications of hydrocarbons.
Hydrocarbons are used as fuels (gasoline, diesel), lubricants, plastics, and many other products in everyday life.
