Solutes with Hexane
Part 2: Conductivity of the substances
Part 3: The liquids water, ethanol and hexane were mixed each other in all the possible combinations. Only one homogeneous and colourless mixture was found combining water and ethanol. No miscible solution was formed and in every other test done, two clearly visible colourless layers were formed.
Part 4: The three different solids were heated to test their melting point, the aim was to find who had the lowest and the highest boiling point.
Part 5: Polarity of the liquids:
Analysis:
In first place we must say that the intramolecular forces have a major importance to determine the results in the different tests. Intramolecular forces like the ones found in compounds like Calcium Chloride and all other substances determine properties like bonding or boiling and melting point. Because of this we can find the difference in for example test 4, the intramolecular forces of ionic compounds are much stronger than the ones in bonding of diatomic molecules, however the intramolecular force found in bonds of covalent compounds of three dimensional arrays such as graphite, are stronger than the ones in some ionic compounds. This is the reason why Iodine has the lowest melting point and graphite has the highest even more than ionic compounds such as Calcium Chloride. So comparing the actual results with the results given in the hypothesis we can determine that the prediction was correct based on the reasons given above.
Bonding gives the capacity of conductivity for example ionic compounds arepoor conductors as solids because electrons are tied up by ions. However they are good conductors when melted or dissolved because ionic bonds are broken and electrons are free to move around. This is the reason why calcium chloride is capable to conduct electricity when is dissolved but incapable when is solid. In the case of covalent bonds we observe that they are poor conductors as solid and liquid because all electrons are tied up in covalent bonds, this explains the conductivity of iodine. Comparing the results of test 2 with the ones predicted in the hypothesis we can say that it was correct as the results matched perfectly. All of this is due to the reasons explained above.
Also the intramolecular forces can determine polarity of the substance. The polarity is determined by the way which forces “pull” and this is determined by bonding. Here is the structure of some of the molecules used during the practical and their respective polarity.
Hexane (non polar) Water (polar)
So by using this property we can determine that substances like water and ethanol are polar substances while hexane is a non-polar. In response to this we must say that the hypothesis of test 5 was wrong because it determined that only water was a polar molecule, also because it stated that polarity was determined by the conductivity of electricity which is wrong because is determined by the direction of the charges.
Also because of the interaction of intermolecular forces we can stand the solubility. Properties of intermolecular forces state that polar substances dissolve with polar substances because there are mutual forces of attraction which enable solute and solvents to become separated. This is the reason why calcium chloride can be dissolved in water and in ethanol. In the case of non polar molecules is stated that non-polar and non-polar are able to dissolve because only weak forces attract solute molecules to one another and only weak forces attract solvent molecules to one another. This is the reason why Iodine can be dissolved in hexane. Looking at this we must say that the hypothesis of test 1 was correct because it stated the solubility of calcium chloride in water and of iodine in hexane. Also suggested that graphite was not soluble in anything which based on the properties above and the practice is true.
Based on the properties of solubility, we can say that the same happens with miscibility of liquids and therefore water and ethanol are miscible. In comparison with the prediction of test 3 we can say is wrong because water can be mixed with ethanol because of the principle of polarity. The hypothesis said that water could not be mixed with either ethanol nor hexane which is obviously wrong as it is miscible with ethanol.
Errors and Improvements:
In my opinion we committed various errors specially when managing the substance. For example we made a lot of mistakes because we took a lot of substrate or in the other hand a lot of the solvent. Also we made mistakes when looking at the reactions because we didn’t waited much time so we have may missed something important in the reaction. The procedure had mistakes itself for example in test 4 there was not a way to determine who had the highest melting point because we didn’t have equipment that could reach those high temperatures. The same happened with test 2 because the charges were so little and the ammeter didn’t showed small units so maybe here was a conductive substance we weren’t able to see because of the equipment.
Conclusion: Looking at the results of the five tests and to the analysis given of the mentioned results we can conclude that all of the substances in the practical have certain characteristics according to their molecular forces (intramolecular and intermolecular). Those characteristics will be listed on the table below