Organic Chemistry Flashcards
(18 cards)
What are hydrocarbons?
Compounds containing only hydrogen and carbon. Found in crude oil and fossil fuels.
What is the general formula for alkanes?
CₙH₂ₙ₊₂ (e.g., methane CH₄, ethane C₂H₆).
How do alkenes differ from alkanes?
Alkenes have a double bond (C=C); alkanes are saturated (single bonds).
What is fractional distillation?
Separating crude oil into fractions by boiling points (longer chains = higher boiling points).
Why is cracking important?
Converts long-chain hydrocarbons into shorter, more useful alkanes and alkenes.
What conditions are used for cracking?
High temperature and a catalyst (e.g., silica/alumina).
What are the products of complete combustion?
Carbon dioxide (CO₂) and water (H₂O).
How do you test for an alkene?
Add bromine water: turns from orange to colourless if C=C bond is present.
How is ethanol made by fermentation?
Glucose → ethanol + CO₂. Conditions: yeast, 30–40°C, anaerobic.
What uses come from the refinery gas fraction?
Bottled gas for heating/cooking.
What uses come from the gasoline fraction?
Fuel for cars (petrol).
Why are most polymers problematic?
Non-biodegradable; accumulate in landfills/oceans, harming ecosystems.
What causes incomplete combustion?
Limited oxygen. Produces carbon monoxide (toxic) and soot (carbon particles).
Give two uses of ethanol.
Alcoholic drinks, fuel for cars, or solvents.
What is a monomer?
Small molecules that form polymers (e.g., ethene → polyethene).
What is the diesel fraction used for?
Fuel for lorries, trains, and some cars.
Why are alkenes called ‘unsaturated’?
They have a double bond, meaning they can undergo addition reactions (e.g., with bromine water).
How does polymer disposal affect the environment?
Non-biodegradable plastics persist for centuries, harming wildlife and ecosystems.
