F322 - Basic Concepts and Hydrocarbons Flashcards
What is a molecular formula?
The actual number of atoms of each type of element present in a molecule.
What is an empirical formula?
The simplest whole-number ratio of atoms of each element present in a compound.
What is a general formula?
The simplest algebraic formula of a member if a homologous series.
What is a structural formula?
The minimal detail that shows the arrangement of atoms in a molecule.
What is a displayed formula?
The relative positioning if atoms and the bonds between them for a molecule.
What is a skeletal formula?
The simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups.
What is a homologous series?
A series of organic compounds having the same functional group but with each successive member differing by CH2.
What is meant by the term functional group?
A group of atoms responsible for the characteristic reactions of a compound (its chemical properties).
What are the names of the first ten alkanes in order?
Methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane.
What is meant by the term structural isomers?
Compounds with the same molecular formula but different structural formulae.
What is meant by the term stereoisomers?
Compounds with the same structural formula but a different arrangement of atoms in space.
What are the features of a compound which make it exhibit stereoisomerism?
C=C Double bond (restricts rotation) and having two different groups attached to each C in the C=C double bond.
What is homolytic fission?
Breaking of a covalent bond to form two radicals.
What is heterolytic fission?
The breaking of a covalent bond to form a cation and an anion.
What do curly arrows represent in a reaction mechanism?
The movement of an electron pair to show the breaking or making of a covalent bond.
How is percentage yield calculated?
Actual yield x 100/theoretical yield
What is atom economy?
The sum of the molecular mass of the desired products x 100%/sum of molecular masses of all products (or reactants)
Why is the atom economy of addition reactions 100%?
They only produce one product which is the desired product. No waste products are formed.
How could you increase the atom economy of a substitution reaction?
Find a use for the wasteful products.
What is a hydrocarbon?
A compound that contains carbon and hydrogen ONLY.
What does the term saturated hydrocarbon mean?
Compound that contains only C-C single bonds (no C=C double bonds).
How is fractional distillation used to separate crude oil?
Separates based in differing boiling points. Low boiling points are collected at the top of the column and high boiling points at the bottom.
What is the shape and bond angle around the carbons in an alkane?
Tetrahedral and 109.5
Why do the boiling points of alkenes increase with increasing chain length?
There are more points of surface contact and therefore more van der Waals’ forces.
Why do the boiling points of alkenes decrease with increased branching?
There are less points of surface contact and therefore fewer van der Waals’ forces.
What causes incomplete combustion?
Insufficient supply (lack) of oxygen
Why is carbon monoxide dangerous?
It bonds to the iron of haemoglobin in the blood in preference to oxygen.
What is cracking?
Taking long chain hydrocarbons and breaking them into smaller pieces including branched isomers and alkenes.
Why do we process hydrocarbons using cracking?
Turns larger less useful fractions into more useful smaller fractions suitable for fuels and the production of polymers.
What is a radical?
A species with an unpaired electron.
What is required for the formation of a halogenoalkane from a halogen molecule?
Ultraviolet radiation
What are the limitations of using free radical substitution for making halogenoalkanes?
Further substitution can take place forming a mixture of products.
What is an unsaturated hydrocarbon?
Contains a C=C double bond
How is a pi bond formed?
The overlap of adjacent p orbitals.
What is the shape and bond angle around each of the carbon atoms in the C=C double bond?
Trigonal planar and 120.
Where do small molecules et added during an addition reaction?
Across the C=C double bond.
What is meant by the term electrophile?
An electron pair acceptor
What is addition polymerisation?
Forming a polymer by a repeated addition reaction.
What is a monomer?
The small molecule used to build a polymer molecule.
What are the reagents in the manufacture if margarine?
Unsaturated vegetable oils, hydrogen and a nickel catalyst.
How can waste polymers be processed?
Sort and recycle, combusted for energy production, and as a feedstock for cracking to make other plastics.
How can toxic HCl be removed from the atmosphere?
React with an alkali
What type of polymers are being produced to help minimise environmental damage?
Biodegradable polymers, compostable polymers and photodegradable polymers
