Chem Topic 7

• What is crude oil?

  A mixture of hydrocarbons; consisting only carbon & hydrogen molecules. Its made from organisms and plankton buried underwater and compressed for millions of years
• What are the two types of hydrocarbons?

  Alkanes & Alkenes
• What are alkanes?

  A hydrocarbon made up of single-covalently bonded carbon atoms surrounded by hydrogen atoms

  Methane, Ethane, Propane, Butane

  General formula is C H

  n 2n+2
• What is the process of fractional distillation?

  A mixture is heated: vapours rise through a column which is hot at the bottom, and cooler at the top. Vapours condense when they reach a part of the column that is below the temperature of their boiling point.
• What do longer alkanes have?

  High boiling point due to more energy needed to overcome the stronger intermolecular forces, so they recondense lower down the fractional column
• What is the word equation for complete & incomplete combustion?

  Complete: fuel + oxygen -> carbon dioxide + water

  Incomplete: fuel + oxygen -> carbon monoxide/carbon + water
• What do longer and shorter alkanes have?

  Longer: high viscosity (flow easy)

  Shorter: more flammable
• What do longer and shorter alkenes have?

  Longer: low viscosity

  Shorter: less flammable
• What are hydrocarbons used for?

  Fuel, solvents, lubricants, detergents and polymers
• What are polymers made from?

  Alkenes/monomers
• What is an alkene?

  A hydrocarbon with a carbon-carbon double bond. Their name ends with -ene.

  General formula: C H

  n 2n
• How do we test for alkenes?

  Bromine water test; if alkenes are present, bromine water will turn orange to colourless due to the bromine atoms bonding to the alkene breaking the double bond.
• What is cracking and when is it used?

  Cracking is used in order to break longer alkanes into a shorter alkane and an alkene due to more demand for shorter alkanes
• What are the 2 type of cracking?

  Catalytic: uses zeolite catalyst at 550 degrees Celsius

  Steam: no catalyst and a higher temp at >800 degrees Celsius
• What is an alcohol?

  An organic molecule with an -OH functional group. Their names end with -ol

  An alcohol can be oxidised to produce a carboxylic acid (-COOH)
• What are polymers?

  Long chained organic molecules of repeating sections made from monomers
• What does an amino acid contain?

  Amino group, carboxyl group, and side chain.
• What is DNA made from?

  DNA (deoxyribonucleic acid) is a two-stranded polymer made from monomers called nucleotides
• What is starch and cellulose a polymer of?

  Starch: polymer of glucose

  Cellulose: polymer of Beta-Glucose