Objective

To study, evaluate and compare the properties of several substances and relate them to their type of bonding (ionic, covalent or metallic).

Theoretical background

The properties of substances are related to the kind of bonding present in those substances. The type of bonding depends on the atoms present and is related to their position in the periodic table. 

There are 3 types of compounds: 

Ionic compound: Ionic compounds have high melting points and high boiling points, s conduct electricity when they are dissolved in water. One atom completely removes one or more electrons from another to form charged ions with full outer shells. The actual ionic bond is the electrostatic attraction between the positive and negative charges.

Covalent compound: Most covalent compounds have relatively low melting points and boiling points. When dissolved in water, covalent compounds don't conduct electricity. 
Atoms share electrons to complete their outer shell. The actual covalent bond is due to the attraction between the pair of shared electrons and the 2 nuclei.

Metallic compound: Conduct electricity and generally a high melting and boiling points strong. Metal atoms lose their outer electrons to form a structure of positive metal ions and a sea of delocalised electrons. The metallic bond is the strong attraction between the metal ions and the electrons.

Materials:

• Substances A to D 
• Conductivity meter
• Test tubes 
• Distilled water
• Spatula 
• Acetone
• Bunsen burner

What is acetone?

Acetone is an organic solvent. It is colourless and flammable. It´s formula is C3H6O. It is presented in blood and urine in our organism, however, it is also produced on labs. Its main function is cleaning and nail polish remover. Acetone is a good solvent for many plastics and some synthetic fibres,

Our Results:










Expected Results:

Conclusion:

Once I have finished the experiment, I have come up with some conclusions. As Iron (II) Sulfate is an ionic bond, it has a positive and a negative part, it has polarity. Water also has polarity as Oxygen is – and Hydrogen is +.  This means that the positive part of Iron (II) Sulfate, which iss Iron attracts toward oxygen and Hydrogen bonds with sulfur. This makes it dissolve and make a homogenous solution. Paraffin doesn’t dissolve in water because it is a covalent bond and there is no polarity. Iron doesn’t dissolve because it is a metallic bond and the bond of a metallic bond it is to strong and it is difficult to separate. Finally carbon doesn’t dissolve neither because it is a metallic bond and it can´t separate so easily. 
Acetone, however, just has few porality. 
Iron conducts electricity because it is a metallic bond where atoms are attached between strongly but there is a small gap where electrons flow. Graphite conducts electricity due to the electrons delocalized between each carbon layer. They can move freely so they can conduct electricity very well. It is giant covalent structure.
If we compare our results with the ones of the other table, we have worked very well in boiling point. It wasn’t very difficult because we just had to hold the test tube and if it took a short period of time until it boiled, it had a low boiling point. If it spent more than a minute medium and finally, if it spent more than 3 minutes, a high one. As we see, most of the compounds had a high boiling point.
In the aspect of dissolution on water, we did it very well. Iron (II) Sulfate was the only substance that dissolved, as it was the only Ionic Compound. However, we made a mistake in the dissolution of acetone. Despite we thought and proved that Paraffin dissolves in acetone, it didn’t. Paraffin is supposed to dissolve in it as it is a covalent molecule, and acetone is an organic substance.

C- Carbon-very high- Matt black- Did not dssolve in water-do not dissolved in acetone - Does not conduct
B- Parafina-Low- Transparent, small, round- Did not dissolve in water- dissolved in acetone- Does not conduct
A- Iron(II) Sulphate- Very High- Powdery, greenish- Dissolved in water-do not dissolved in acetone- Does not conduct-does not conduct in water
D- iron-Very high- A nail- rusty, shiny- Did not dissolve in water-do not dissolved in acetone- Does conduct

Evaluation:

Some of the mistakes that could have been done during this experiment could be when any of  the A, B, C or D substances are picked, the labels might have been placed with the substance that does not belong to it. Also the performers of this experiment might have read a label and written it down on a laptop, but then did the experiment with a different one.

When heating the substances, whoever held the substance with a clamp, might have
placed it away from the bunsen burner, rather that just over it. This would
affect the boiling points, as they would actually be lower.

Seen how the conductivity meter is a machine whose performance is not affected by
the performers of the experiment, but itself. This is because it’s batteries
might have ran out, or it simply doesn’t work. This would mean that substances
that are conductive would have been recognized as non conductive substances.

In order to get the most accurate possible results the same thermometer must be used for all substances. This is because two different thermometers might not show the same results for the same temperature.

To get the same mass for every substance, a digital scale (or a regular scale) could be used in order to get accurate results. This would mean that the substances will be compared fairly, as different amounts could alter the results and prove the theory wrong, when it actually is not wrong.