organic chemistry Flashcards
What are organic compounds?
Compounds that contain carbon, excluding metal carbonates, carbon dioxide, and carbon monoxide.
Define hydrocarbon.
A compound that contains only hydrogen and carbon atoms.
What does the empirical formula show?
The simplest possible ratio of the atoms in a molecule.
What does the molecular formula indicate?
The actual number of atoms in a molecule.
What is a general formula?
Shows a ratio of atoms in a family of compounds in terms of ānā, where n is a varying whole number.
What is the general formula for alkanes?
C_nH_(2n+2).
What are displayed formulae?
Shows the spatial arrangement of all the atoms and bonds in a molecule.
Define structural formula.
Shows enough information to make the structure clear, but omits most actual covalent bonds.
What is a homologous series?
A series of organic compounds with the same general formula, similar chemical properties, and the same functional group.
What is a functional group?
A group of atoms bonded in a specific arrangement that influences the properties of the homologous series.
What are isomers?
Compounds that have the same molecular formula but different displayed formulae.
True or False: Isomers can show similar physical and chemical properties.
True.
What are the two parts of the names of organic compounds?
The prefix (or stem) and the suffix.
What does the prefix in an organic compound name indicate?
How many carbon atoms are present in the longest continuous chain in the compound.
What does the suffix in an organic compound name indicate?
The functional group present in the compound.
Fill in the blank: The number of carbon atoms in methane is _______.
1
What is a substitution reaction?
A reaction where one functional group is replaced by another.
What is an addition reaction?
A reaction where two or more molecules combine to form a larger molecule with no other products.
What is combustion?
The reaction of an organic substance with oxygen to form carbon dioxide and water.
What are the products of complete combustion?
Carbon dioxide and water.
What are the products of incomplete combustion?
Carbon monoxide and water.
What is crude oil?
A mixture of different hydrocarbons that is not very useful in its raw form.
What is fractional distillation?
A process used to separate the different fractions of crude oil based on their boiling points.
What are fractions in crude oil?
Groups of hydrocarbons of similar chain lengths.
How does the size of a hydrocarbon molecule affect its fraction?
It determines the fraction into which it will be separated based on carbon and hydrogen atom count.
What are alkanes?
Compounds of carbon and hydrogen with only single bonds between them.
What happens to hydrocarbons during fractional distillation?
They vaporize and condense at different levels in a fractionating column based on boiling points.
What is viscosity?
The ease of flow of a liquid; high viscosity means thick and less flowable.
How does carbon chain length affect viscosity?
Increased carbon atoms lead to higher viscosity due to greater intermolecular attraction.
What is volatility?
The tendency of a substance to vaporize.
As molecular size increases, what happens to volatility?
Volatility decreases due to increased molecular attraction.
What is the boiling point trend for crude oil fractions?
Boiling point and viscosity increase as the carbon chain length increases.
What are some uses of liquefied petroleum gas?
Domestic heating and cooking.
What is the primary use of petrol?
Fuel for cars (gasoline).
What is combustion?
An exothermic reaction where a fuel releases heat energy when burned.
What are the products of complete combustion of a hydrocarbon?
Water and carbon dioxide.
What is carbon monoxide and why is it dangerous?
A toxic, odorless gas that binds to hemoglobin, preventing oxygen transport.
How are nitrogen oxides formed?
When nitrogen and oxygen react under high pressure and temperature conditions.
What are the adverse effects of nitrogen oxides?
Acid rain, photochemical smog, and respiratory issues.
What causes sulfur dioxide formation?
Oxidation of sulfur impurities in fossil fuels during combustion.
How is acid rain formed from sulfur dioxide?
Sulfur dioxide dissolves in rainwater to form sulfuric acid.
What is cracking in the context of hydrocarbons?
An industrial process to break long-chain hydrocarbons into smaller, more useful molecules.
What conditions are required for catalytic cracking?
Heating hydrocarbons to 600-700 Ā°C and using a hot powdered catalyst.
What types of products result from cracking?
A mixture of shorter alkanes and alkenes.
What is the relationship between supply and demand for crude oil fractions?
Certain fractions are in higher demand than supply, leading to cracking to produce more useful fractions.
Fill in the blank: Cracking is an _______ reaction.
endothermic
True or False: Gasoline and petrol refer to the same substance.
True
What are alkanes?
A group of saturated hydrocarbons.
What does saturated mean in the context of alkanes?
They only have single carbon-carbon bonds; there are no double bonds.
What is the general formula of alkanes?
CnH2n+2.
How do alkanes typically behave chemically?
Generally unreactive, but they undergo combustion, can be cracked, and react with halogens in light.
What is the major component of natural gas?
Methane.
What is the molecular formula for methane?
CH4.
What is the molecular formula for ethane?
C2H6.
What is the molecular formula for propane?
C3H8.
What is the molecular formula for butane?
C4H10.
What is the molecular formula for pentane?
C5H12.
What is a substitution reaction?
One atom is swapped with another atom.
Under what conditions do alkanes undergo substitution reactions with halogens?
In the presence of ultraviolet radiation.
What is the equation for the reaction between methane and bromine in the presence of UV radiation?
methane + bromine ā bromomethane + hydrogen bromide.
What is the equation for the reaction between methane and chlorine?
methane + chlorine ā chloromethane + hydrogen chloride.
What are the products of alkane reactions with halogens called?
Halogenoalkanes or haloalkanes.
What are some uses of halogenoalkanes?
- Solvents
- Refrigerants
- Propellants
- Pharmaceuticals.
What does CFC stand for?
Chlorofluorocarbon.
Why are CFCs being phased out?
They cause damage to the ozone layer.
What are alkenes?
Alkenes are unsaturated hydrocarbons.
What is the general formula of an alkene?
CnH2n.
What type of bond do all alkenes contain?
A double carbon bond (C=C).
What is the functional group of alkenes?
The double carbon bond (C=C).
List the first four alkenes and their molecular formulas.
- Ethene: C2H4
- Propene: C3H6
- But-1-ene: C4H8
- Pent-1-ene: C5H10.
What are compounds with a C=C double bond also called?
Unsaturated compounds.
Why are alkenes more reactive than alkanes?
Because they contain a double carbon bond that can break and form single bonds.
What happens to the carbon atoms when the C=C bond opens?
Each carbon atom forms 4 single bonds instead of 1 double and 2 single bonds.
What does the numbering in butene, pentene, and hexene refer to?
The carbon atom where the C=C bond begins, counting from the left.
What is the bromine water test used for?
To distinguish between alkenes and alkanes.
What color is bromine water, and what happens when it is added to an alkene?
Bromine water is orange; it loses its color (decolourises) when added to an alkene.
What happens to bromine water when added to an alkane?
It remains as an orange solution.
True or False: Alkenes are saturated compounds.
False.
What allows alkenes to react in ways that alkanes cannot?
The presence of the C=C double bond.
What is the area of high electron density in alkenes?
The carbon-carbon double bond.
What are polymers made from?
Polymers are made by linking together large numbers of smaller molecules called monomers
This process is called addition polymerisation.
What is the process called when monomers link to form polymers?
Addition polymerisation
This involves covalent bonds between the monomers.
What type of bonds do addition polymers contain?
Single bonds
This occurs after the C=C bonds in monomers break during polymerisation.
What is required for polymerisation reactions?
High pressures and the use of a catalyst
These conditions facilitate the polymerisation process.
Name two types of polymers.
- Synthetic polymers
- Natural or biological polymers
Synthetic polymers are man-made, while natural polymers occur in nature.
What are the four polymers named in the specification?
- Poly(ethene)
- Poly(propene)
- Poly(chloroethene)
- (Poly)tetrafluoroethene
Make sure to be able to draw the monomer and repeating unit for each one.
What is a repeat unit in a polymer?
A repeat unit is the part of the polymer that is repeated to form the entire molecule
It is derived from the monomer.
True or False: Addition polymers are biodegradable.
False
Addition polymers are chemically inert and do not easily biodegrade.
What is a major environmental problem associated with addition polymers?
Disposal of addition polymers
They are non-biodegradable, which leads to landfill issues.
What happens to waste polymers in landfills?
They take up valuable land and cannot be broken down by microorganisms
This leads to landfills filling up quickly.
What are the consequences of incinerating addition polymers?
- Release of carbon dioxide
- Release of toxic hydrogen chloride gas (if chlorine is present)
- Production of carbon monoxide from incomplete combustion
These gases contribute to environmental issues.
Fill in the blank: Addition polymers are formed by the joining up of many small molecules with strong ______ bonds.
C-C
This strength contributes to their unreactivity.
