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4.1 IntroductionEdexcel IGCSE Chemistry: Flashcards

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What is a hydrocarbon?

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What is a hydrocarbon?
A compound that contains hydrogen and carbon atoms only.
Why can carbon form so many different compounds?
It forms four strong covalent bonds, including bonds to other carbon atoms, allowing chains, branches and rings.
Define empirical formula.
The simplest whole-number ratio of atoms of each element in a compound.
Define molecular formula.
The actual number of atoms of each element in one molecule.
What does a general formula show?
An algebraic formula, e.g. CnH2n+2, that applies to every member of a homologous series.
What is the difference between structural and displayed formula?
Structural formula shows how atoms are grouped along the chain without every bond; displayed formula shows every atom and every bond.
Define homologous series.
A family of compounds with the same general formula and functional group, differing by CH2 between successive members.
Define functional group.
An atom or group of atoms that gives an organic molecule its characteristic chemical reactions.
Define isomerism.
The existence of two or more compounds with the same molecular formula but different structural formulae.
Name the two structural isomers of C4H10.
Butane (unbranched) and methylpropane (branched).
What does the IUPAC stem 'but-' tell you?
That the longest carbon chain in the molecule has four carbon atoms.
List the IUPAC stems for chains of 1 to 6 carbons.
meth-, eth-, prop-, but-, pent-, hex-
Define a substitution reaction.
A reaction in which an atom or group of atoms is replaced by a different atom or group.
Define an addition reaction.
A reaction in which two molecules combine to form a single product with no atoms lost.
What is combustion?
A reaction in which a substance reacts with oxygen, releasing heat energy.