ionic compounds investigation

As nonmetals react with metals, ionic compounds are formed. Since they gain or lose electrons to form ionic bonds, ionic compounds have a charge. Ionic compounds have intense ionic attraction powers from all directions, resulting in the forming of a massive structure. At room temperature, ionic compounds remain as solids that do not perform electricity because both electrons are involved in bonding and are not able to travel. Because of mobile ions, they can only conduct electricity when molten. Ionic compounds dissolve in water as the particles of the solvent overcome the force of attraction between the ions. Ionic compounds are mostly used in the electrolysis (Hill, 2000, p. 33). _x005FInvestigating covalent compounds
Melting points of the halogens
Halogen Mr (pm) Tm (ºC) Tm (K) Fluorine, F2 143 -220 53.15 Chlorine, Cl2 199 -101 172.15 Bromine, Br2 228 -7 266.15 Iodine, I2 266 114 387.15 Plot a graph Tm (ºC) v Mr of halogen using graph paper.

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State & explain the trends in terms of the type & size of the intermolecular forces which exist in the substances.
The diatomic molecules are held together by van der Waals dispersion forces between neighbouring molecules. The size of the molecules increase down the group. The larger the molecules, the more electrons a molecule has, the more temporary dipoles are created for the forces. Therefore, the intermolecular forces increase down the group from fluorine to Iodine (Verma, 2007, p. 45).
Boiling points of the homologous series of alkanes (C1-8)
Alkanes Mr Tb (ºC) Tb (K) Methane, CH4 16 -162 111.15 Ethane, C2H6 30 -89 184.15 Propane, C3H8 44 -42 231.15 Butane, C4H10 58 0 273.15 Pentane, C5H12 72 36 309.15 Hexane, C6H14 86 69 342.15 Heptane, C7H16 100 98 371.15 Octane, C8H18 114 126 399.15 Plot a graph Tb (ºC) v Mr of alkanes using graph paper.

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State & explain the trends in terms of the type & size of the intermolecular forces which exist in the substances.
Alkane molecules are held together intermolecular van der Waals forces which increases with increase in the number of molecules. Increase in van der Waals forces is due to the increase in surface area of a molecule which provides high chances for interaction between molecules and also the growing chain leads to an increase in the number of electrons that are able to interact between molecules (Petrucci, 2007, p. 42).
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Complete the table for the relative solubility in water of the homologous series of alcohols (C1-6) access data from the power point available on Moodle.
Alcohols Mr Relative solubility in water Methanol, CH3OH 32 ∞ Ethanol, C2H5OH 46 ∞ Propanol, C3H7 OH 60 ∞ Butanol, C4H9 OH 74 0.11 Pentanol, C5H11 OH 88 0.030 Hexanol, C6H13 OH 102 0.0058
Comment on the general trend
Solubility in water decreases with increase in the hydrocarbon chain in the alcohol molecule.
Explain the trends in terms of the type & size of the intermolecular forces which exist in the substances.
There exists hydrogen bonds between the hydrogen atoms and oxygen atoms because the electrons used in bonding are pushed away towards the oxygen atoms which are electronegative. There are also van der Waals forces between the molecules. They get stronger with increase in the size of hydrocarbon chain. Therefore, increase in the size of the alcohol results in the increase in the number of hydrogen and van der Waals forces hence and increase in the intermolecular bonds (Hill, 2000, p.20).

References
Hill, Graham, and John Holman. Chemistry in Context. 5th ed. United Kingdom: Nelson Thornes, 2000. 224-25.
Petrucci, Ralph H. Genereal Chemistry: Principles and Modern Applications. 9th Ed. New Jersey: Pearson Education Inc, 2007. 920-928.
Verma, Norah .K, Billha Kapila, and Sonny.K. Khanna. Comprehensive Chemistry XII. New Delhi: Laxmi Publications, 2007. 718-30.