1. A table of results:
Iron (III) sulfate
|
Naphthol
|
Starch
|
iron filings
| |
Melting point?
|
high
|
low
|
high
|
high
|
Soluble in 10 ml of acetone?
|
not soluble
|
soluble
|
not soluble
|
not soluble
|
Soluble in 10 ml of water?
|
not soluble
|
not soluble
|
not soluble
|
not soluble
|
Conducts electricity?
|
no
|
no
|
no
|
no
|
2. The type of bonding present in each substance:
Iron (III) Sulfate - FeSO4
This substance has ionic bonding. Ionic bonds are made up of positive ions (cations) and negative ions (anions). Also, ionic bonds has high melting point and doesn´t conduct electricity, as it shows in the previous table.
Naphthol
This substance has a covalent bonding because it is only need enough energy to overcome the weak forces of attraction. Also, as we can see in the table of results, the melting point is low and it doesn't conduct electricity.
Starch
As Iron (III) sulfate, this substance has covalent bonding because it has a high melting point, therefore, looking foward our results, it will be a giant covalent structure. This is because we need to break all the strong electrostatic attraction and this requires a lot of energy.
Iron filings:
This substance also have ionic bonding, as Starch, and Iron (III) Sulfate, they have high melting point and they are insulators because Ionic solids do not conduct electricity.
3. A secondary table to show “expected” results. (Research the type of bonding and the expected results for the test that you carried out).
Iron (III) sulfate
|
Naphthol
|
Starch
|
iron filings
| |
Melting point?
|
high
|
low
|
high
|
high
|
Soluble in 10 ml of acetone?
|
not soluble
|
soluble
|
not soluble
|
not soluble
|
Soluble in 10 ml of water?
|
soluble
|
soluble
|
not soluble
|
not soluble
|
Conducts electricity?
|
no
|
no
|
no
|
no
|
As we can see in this table, there are some results that have changed. In the results of solute which dissolves in water we can onserve that are two expected results that we´ve corrected from the table of before.
This is because solubility in water depends on the polarity of each substance.We say a molecule is polar of one side of the molecule experiences more negative charge than another.
4. A conclusion comparing the actual results with the expected results.
We can see how the two substances with iron (Iron (III) sulfate and Iron Filings) have high melting points, so we can conclude, that in general, iron has a high melting point. The other two substances had the same elements just with different quantities and structures. Starch clearly has a complex structure, compared to naphthol, that has a simple one. This makes starch have a high melting point, This shows us the substances with ionic bonding have high melting point, and the ones with covalent bonding, low melting point.
When testing the solubility in water, we get different results for irons, the filings aren't soluble, as well as starch, that didn't, Naphthol and iron sulphate dissolved in water, which means they are polar, as water is polar. When doing the same test, but with acetone, we found out different results. Acetone is less polar than water, so this got naphthol, starch and iron filings to dissolve, Only iron sulphate didn't, this gets us to see, that bonding has nothing to do with solubility, but polarity does.
To end we tested the conductivity, none was a conductor, the substances with ionic bondings (Iron sulphate, iron filings and starch) are insulator, naphthol happens to be an insulator as well.
Even though most irons do conduct electricity, in our experiment we tested that that's not always like that. Iron filing do contain iron, and does not conduct electricity, that's because the individual particles of iron are removed far away from each other, and therefore they are to far from each other to conduct electrical current.
Even though most irons do conduct electricity, in our experiment we tested that that's not always like that. Iron filing do contain iron, and does not conduct electricity, that's because the individual particles of iron are removed far away from each other, and therefore they are to far from each other to conduct electrical current.
In our opinion this experiment has helped us a lot and we find it interesting too. It has helped us understand most of the unit we are studying in the physics and chemistry subject. We understand it by doing this experiment, In which we´ve mixed a solvent with a solute (water and acetone). Through these examples we have seen which were soluble in water and acetone and which not. Also, we’ve learned the type of melting point, if they conduct electricity or not and the type of chemical bonding of these several substances.
5. An evaluation that suggest improvements that could be made to your method.
Several things we should change in out method to improve the experiment. Our results aren't 100% accurate. For example, the first problem we can find out that could be improved is the way of shaking every test tube with our hand. Shaking it with our hand will not present accurate results at the end. The solution to this is to use a specific mixer and mix every substance in a specific time and the results will be more accurate.
Another point to consider is, even though we tried to be precise when we poured the substances in every test tube, we maybe weren't accurate and didn't use the same amount of each substance. The solution to this would be to take an instrument to precisely measure it, or to spend more time on it.
To improve the experiment, we should had repeated it again to get more precisse results, but there's not enough time, but in general, I think the experiment was realized in an aceptable way but we could improve several things.
For the next time, we will try to be as accurate as possible in every aspect of the experiment. From preparation, to how we take and analyze the results.
Another point to consider is, even though we tried to be precise when we poured the substances in every test tube, we maybe weren't accurate and didn't use the same amount of each substance. The solution to this would be to take an instrument to precisely measure it, or to spend more time on it.
To improve the experiment, we should had repeated it again to get more precisse results, but there's not enough time, but in general, I think the experiment was realized in an aceptable way but we could improve several things.
For the next time, we will try to be as accurate as possible in every aspect of the experiment. From preparation, to how we take and analyze the results.
6. A minimum of 2 references (APA format).
Bibliography: Ausetute.com.au, (2014). Chemistry Tutorial : Ionic Bonding. [online] Available at: http://www.ausetute.com.au/ionicbond.html [Accessed 12 Oct. 2014].
Bibliography: Hyperphysics.phy-astr.gsu.edu, (2014). Chemical Bonds. [online] Available at: http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/bond2.html [Accessed 13 Oct. 2014].
Bibliography: Hyperphysics.phy-astr.gsu.edu, (2014). Chemical Bonds. [online] Available at: http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/bond2.html [Accessed 13 Oct. 2014].
