Part 11 Chemistry of Carbon Compounds Flashcards
State one medical application of aspirin.
Pain killing // reducing fever // anti-inflammatory drug used for treating arthritis // reducing the risk of heart attacks and strokes
Explain why soap has cleansing properties.
It reduces the water surface tension so that water can spread and wet the surfaces. / It is a wetting agent so water can spread and wet the surfaces.
The hydrocarbon tails of the detergent particles dissolve in the oil, while the ionic heads of detergent particles dissolves in water.
Water molecules attract the hydrophilic ionic heads and bring the oil into water. By stirring, the oil breaks up into tiny droplets and these droplets cannot come together again due to the repulsion between ionic heads.
What is meant by the term “isomers” ?
Isomers are compunds with the same molecular formula but different structures or different arrnagements of atoms in space
Which one usually has has higher melting point, cis-isomer / trans-isomer ?
cis-isomers, It has multiple polar bonds. The polarity of the bonds cannot be cancel out. Therefore the molecule is polar. More energy is needed to seperate the molecules.
Which one usually have a higher boiling points, cis-isomer / trans-isomer
trans-isomer,it has a more symmetrical structure. The molecules can pack more closely in the solid state. Thus, the intermolecular forces holding the molecules together are stronger. More energy is needed to overcome the these intermolecular forces.
Describe the difference in physical property between a pair of enantiomers.
The two enantiomers can rotate the plane of plane-polarised light by the same extent, but in opposite direction.
State Markovnikov’s rule.
In the addition reaction of hydrogen halide (HX) to the C=C double bond of an alkene, the hydrogen atom in HX is added to the carbon atom with the greater number of hydrogen atoms.
What is meant by the term “addition polymerisation” ?
Addition polymerisation is a reaction in which molecules can join together repeatedly to form polymer molecules, without the elimination of small molecules
