• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9

Section 1.4 ORGANIC HALIDES

Extracts from this document...

Introduction

Section 1.4 ORGANIC HALIDES Organic halides: A compound of carbon and hydrogen in which one or more hydrogen atoms have been replaced by halogen atoms. Functional group: R - X Used in: * Freons (chlorofluorocarbons, CFCs) used in refrigerators and air-conditioners * Teflon (polytetrafluoroethene), the nonstick coating used in cookware and labware * The insecticide DDT (dichlorodiphenyltrichloroethane) and the PCBs (polychlorinated biphenyls) used in electrical transformers Naming Organic Halides: Consider the halogen atom as an attachment on the parent hydrocarbon. The halogen name is shortened to fluoro-, chloro-, bromo-, or iodo. Preparation: * alkenes and alkynes --> organic halides addition reactions with halogens or hydrogen halides * alkanes and aromatics --> organic halides substitution reactions with halogens or hydrogen halides Pathway to other groups: * alkyl halides --> alkenes elimination reactions, removing hydrogen and halide ions Properties of Organic Halides: The halogen atom on a hydrocarbon chain/ring makes the molecule more polar as the halogens are more electronegative than C and H atoms. Therefore, halogen bonds are more polar than C - H bonds. The increased polarity of alkyl halides increases the strength of the intermolecular forces. Thus alkyl halides have higher boiling points than the corresponding hydrocarbons. The increased polarity makes them more soluble in polar solvents than hydrocarbons of similar size because "like dissolves like". Section 1.5 ALCOHOLS and ETHERS Alcohol: An organic compound characterized by the presence of a hydroxyl functional group; R - OH Preparation: * alkenes --> alcohols addition reaction with ...read more.

Middle

A molecule of water is eliminated and the remaining portions of the two alcohol molecules combine to form ether. This type of reaction, in which two molecules interact to form a larger molecule with a loss of a small molecule such as water, is called a condensation reaction. Section 1.6 ALDEHYDES and KETONES Aldehyde: An organic compound characterized by a terminal carbonyl functional group; that is, a carbonyl group bonded to at least one H atom. Ketones: An organic compound characterized by the presence of a carbonyl group bonded to two carbon atoms. Functional group: >C = O, carbonyl group * aldehydes: * ketones: Preparation: * primary alcohols --> aldehydes controlled oxidation reactions * secondary alcohols --> ketones controlled oxidation reactions Pathways to other groups: * aldehydes --> primary alcohols addition reaction with hydrogen: hydrogenation * ketones --> secondary alcohols addition reaction with hydrogen: hydrogenation Properties of Aldehydes and Ketones Aldehydes and ketones have lower boiling points than analogous alcohols, and are less soluble in water than alcohols; this is to be expected as they do not contain -OH groups and so do not participate in hydrogen bonding. However, the carbonyl group is a strongly polar group due to the four shared electrons in the double C=O bond. Thus, aldehydes and ketones are more soluble in water than are hydrocarbons. The ability of these compounds to mix with both polar and non-polar substances makes them good solvents. ...read more.

Conclusion

bonded to a nitrogen atom. Functional groups: * amines: * amides: Preparation: * amines: RX + NH3 --> amine + HX RX + R2NH --> amine + HX Reactions: amine + carboxylic acid --> amide + H2O (condensation reaction) amide + H2O --> carboxylic acid + amine (hydrolysis reaction) Properties of Amines Amines have higher boiling and melting points than hydrocarbons of similar size, and the smaller amines are readily soluble in water. This can be explained by two types of polar bonds in amines: the N - C bonds and any N - H bonds. These bonds are polar because N is more electronegative than either C or H. These polar bonds increase intermolecular forces of attraction, and therefore, higher temperatures are required to melt or to vaporize amines. Where N - H bonds are present, hydrogen bonding also occurs with water molecules, accounting for the high solubility of amines in water. Since N - H bonds are less polar than O - H bonds, amines boil at lower temperatures than alcohols at similar size. Properties of Amides Amides are weak bases, and are generally insoluble in water. However, the lower-molecular-weight amides are slightly soluble in water because of the hydrogen bonding taking place between the amides' polar N - H bonds and water molecules. Amides whose N atoms are bonded to two H atoms have higher melting points and boiling points than amides that have more attached alkyl groups, this can also be explained by increased hydrogen bonding, requiring higher temperatures for vaporization. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Organic Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Organic Chemistry essays

  1. Marked by a teacher

    What an ester is, how it is made, examples of esters, animal testing issues ...

    4 star(s)

    major reason * Results aren't reliable, as the cosmetic s may only be guaranteed to be safe for a small amount of time and in certain conditions and skin types. * Causes severe side allergic reactions to animals * Animals' skin may not react the same way as human skin

  2. Marked by a teacher

    Investigating the rate of reaction between magnesium and hydrochloric acid

    3 star(s)

    1.0 molar has a rate of 0.041 so if I double the concentration the rate should double and be 0.082, but it isn't as it is 0.16. This shows that there is no pattern in my experiment. However in graph number 2, I have noticed an exponential pattern, which means that as the concentration increases the steeper the graph gets.

  1. Peer reviewed

    The purpose of this lab is to identify two different unknown organic compounds, through ...

    3 star(s)

    Method; (before lab investigation) 1. Take the 3 unknown compound bottles which are provided. 2. Add ___ ml of each unknown liquid into a distilled beaker to save "supplies" so different experiments can be done, to be able to get as accurate results as possible 3.

  2. Burning alcohols.

    dangerous and could easily react with the air and cause an explosion. Prediction I predict that the most efficient fuel will be Pentanol. This is down to the making and breaking of bonds theory. The burning of alcohols is an exothermic reaction because heat is given out.

  1. Esters. Esters are formed from an alcohol and carboxylic acid; this is an ...

    It is a soluble in propylene glycol, paraffin oil, and kerosene. Ethyl butyrate is one of the most common chemicals used in flavors and fragrances. It can be used in a variety of flavors orange (most common), cherry, pineapple, mango, guava, bubblegum, peach, apricot, fig, and plum.

  2. Polymers. The process in which polymers are formed is called polymerisation. There are two ...

    The active centre reacts and then adds another monomer molecule, then another, then another, regenerating the active centre each time. There are four common types of an active centre: * The free-radical type which is an atom with an unpaired electron. * The carbanion type with a carbon-centred negative ion.

  1. Alkanes and Alkenes

    Conversion: * The fractions are converted into useful products * This is done by cracking which involves breaking large hydrocarbons into smaller ones. Catalyst are used to speed up the process. * Cracking reactions always produce two products. An alkane with a shorter chain than the original one and a short-chain alkene such as ethane.

  2. GCSE Chemistry Revision Notes - everything!

    2H+ (aq) = 2e- ? H2 (g) More and more water keeps splitting up to replace the hydrogen ions as soon as they are discharged. Each time a water molecule splits up it produces a hydroxide ion as well. This means that there is a build up of sodium ions

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work