organic chem ✩

• hydrocarbons are compounds that only contain hydrogen and carbon atoms
• Crude oil is a finite resource formed over millions of years from the remains of tiny sea creatures called plankton buried in mud
• Crude oil is a mixture of molecules called hydrocarbons, which are molecules made up of hydrogen and carbon atoms only
• Methane is a hydrocarbon found in crude oil with the formula CH4, containing one carbon atom covalently bonded to four hydrogen atoms
• The general formula for alkanes is CnH2n+2, meaning if we know the number of carbon atoms (n), we can calculate the number of hydrogen atoms by multiplying the number of carbon atoms by 2 and then adding 2
• Hydrocarbons' properties depend on the size of their molecules:

  • Viscosity: as the size of hydrocarbon molecules increases, they become more viscous
  • Flammability: short-chain hydrocarbons are extremely flammable, while long-chain hydrocarbons are very difficult to burn
  • Boiling point: as the size of hydrocarbon molecules increases, the boiling point also increases
• Alkanes are a family of hydrocarbons, with the first four being methane, ethane, propane, and butane
• Viscosity tells us the thickness of a fluid, with high viscosity meaning the fluid flows slowly; long-chain hydrocarbons are extremely viscous
• Flammability indicates how easily a hydrocarbon burns; short-chain hydrocarbons are highly flammable, while long-chain hydrocarbons are hard to burn
• Boiling point is the temperature at which a liquid turns into a gas; short-chain hydrocarbons have low boiling points, while long-chain hydrocarbons have very high boiling points
• Hydrocarbon fuels release energy when combusted, where the carbon and hydrogen atoms in the fuel react with oxygen, resulting in carbon dioxide and water in complete combustion
• Crude oil is a mixture of molecules called hydrocarbons, with longer chain hydrocarbons having a higher boiling point than shorter chains
• To separate hydrocarbons in crude oil, fractional distillation is used, where crude oil is separated into fractions containing hydrocarbons with a similar number of carbon atoms
• alkenes have the general formula CnH2n
• alkanes have the general formula CnH2n+2, where n is the number of carbons.
• Alkenes can be made using steam cracking or catalytic reforming
• Alkenes can be made from alkanes through cracking or steam cracking.
• Organic molecules are classified by the dominant functional group on the molecule
• Organic compounds with the same functional group, but a different number of carbon atoms, belong to the same homologous series
• Every time a carbon atom is added to the chain in organic compounds, two hydrogen atoms are also added
• Crude oil is a finite resource found in the Earth's crust, mainly consisting of hydrocarbons formed over millions of years from the effects of high pressures and temperatures on biomass remains
• Alkanes are saturated hydrocarbons with single carbon-carbon bonds, forming a homologous series with the general formula CnH2n+2
• Cracking is a process where a long chain alkane is broken down to produce smaller, more useful molecules like shorter chain alkanes and alkenes
• Alkenes have a double covalent bond between two carbon atoms
• Alkenes are more reactive than alkanes
• To test for alkenes, we use bromine water which is orange; when shaken with an alkene, the bromine water turns colorless
• In catalytic cracking, high temperature and a catalyst are used to speed up the reaction
• In steam cracking, high temperature and steam are used
• When balancing cracking equations, the number of carbon and hydrogen atoms must be the same on both sides of the equation
• Cracking is a process where a long chain alkane is broken down to produce smaller, more useful molecules like shorter chain alkanes and alkenes
• Alkenes have a double covalent bond between two carbon atoms
• To test for alkenes, we use bromine water which is orange; when shaken with an alkene, the bromine water turns colorless
• In catalytic cracking, high temperature and a catalyst are used to speed up the reaction; in steam cracking, high temperature and steam are used
• Balancing cracking equations: the number of carbon and hydrogen atoms must be the same on both sides of the equation
• Alkenes contain a double bond between the carbon atoms, which is called the alkene functional group
• Molecules like alkenes are part of a homologous series, where each member has the same functional group
• Each molecule in a homologous series, like alkenes, has an extra carbon atom and two extra hydrogen atoms
• Combustion of alkenes, like alkanes, produces carbon dioxide and water, but alkenes also produce unburned carbon particles due to incomplete combustion
• Incomplete combustion of alkenes results in a smoky flame
• Hydrogenation is the reaction of alkenes with hydrogen, converting the carbon to carbon double bond into a single bond, producing an alkane