Organic Chemistry Definitions

Across

4. Formed from the remains of living organisms when their soft tissue was gradually changed by high temperatures and pressures into a thick, black oil. It is a mixture of hydrocarbons.
7. The addition of hydrogen molecules to an unsaturated molecule, for example converting ethene to ethane.
10. Black powder consisting largely of carbon.
12. Atom or group of atoms that determines the chemical properties of a compound. E.g. C=C for alkenes.
13. Occurs when a hydrocarbon burns in insufficient oxygen. Water is still formed as a product, but carbon monoxide or carbon are formed instead of carbon dioxide
14. Simplest whole number ratio of the atoms of elements present in a compound. It can be worked out from experimental data.
17. Polymerisation of monomers containing a carbon-carbon double bond (C=C). A large number of monomer molecules add onto each other without anything else being formed.
20. A large molecule made when many small molecules (monomers) join together. It consists of many repeat units.
23. A series of compounds with similar chemical properties, the same functional group, and a trend in physical properties. Each member differs from the next by -CH2- .
24. Applicable to all members of a homologous series, an algebraic representation of the molecular formula.
25. Molecules which can join together to form a polymer.
27. A formula that shows all the bonds in a molecule as individual lines. Each line represents a pair of shared electrons in a covalent bond.
28. A substance that evaporates easily.
29. A chemical reaction in which an atom or group of atoms in a molecule is replaced by a different atom or group of atoms.
30. A chemical reaction in which a substance reacts with oxygen (burns) to form products and heat.
32. Compounds made up of hydrogen and carbon only.
33. A finite resource that cannot be replaced, at least not for millions of years.
34. A liquid that is resistant to flow.

Down

1. A chemical reaction in which one molecule adds to another without taking anything away, to form a single product.
2. A piece of equipment used for separating vapours in fractional distillation.
3. Part of the electromagnetic radiation spectrum that has wavelengths between those of visible light and x-rays.
5. A process to separate two or more liquids with similar boiling points (e.g. the components of crude oil).
6. Removing pollutant gases from the gases produced in a combustion reaction.
8. A mixture of methane, ethane, propane and butane. Commonly used for domestic heating and cooking.
9. A homologous series of similar hydrocarbons in which there is at least one carbon-carbon double bond (C=C). These are unsaturated compounds with the general formula CnH2n.
11. A process in which long-chain alkanes are converted to alkenes and shorter-chain alkanes. It is carried out using silica or alumina as a catalyst at a temperature of 600-700oC.
15. A formula that shows how the atoms are joined together in a molecule. Often written in a condensed form by omitting all the carbon-carbon and carbon-hydrogen single bonds.
16. A homologous series of similar hydrocarbons in which all the carbons are joined together by single covalent bonds. These are saturated compounds with the general formula CnH2n+2.
18. Joining up of lots of small molecules (monomers) to make one big molecule (polymer).
19. Substances that when burned in oxygen release heat energy.
21. Rain which has a pH of less than about 5.6. It is caused when water and oxygen in the atmosphere react with sulfur dioxide to produce sulfuric acid, or with various oxides of nitrogen to give nitric acid.
22. Compounds with the same molecular formula but different displayed or structural formula.
26. A substitution reaction in which only one hydrogen atom in an alkane is replaced by a halogen atom.
31. Shows the actual number of each type of atom present in a molecule (covalent compound) or formula unit (ionic compound).