THE PROPERTIES OF MATERIALS
IN THE LAB:
We have tested three substances and their properties. They properties such as: solubility in water or acetone, in they conduct electricity in solid state, their physical state at room temperature (27º approx.), and if they melt with an increase of temperature, all of those together help us determine if they are covalent, ionic or metallic.
SOME OF THOSE CHARACTERISTICS WEREN'T TESTED BECAUSE THERE WEREN'T NEED TO DETERMINE THEIR TYPE
In this lab session we have stated our results in a table and then we have answered some question which helped us to improve our understanding about properties of materials and the types of compounds we are looking at
OUR RESULTS:
QUESTIONS & ANSWERS:
Why do Ionic compounds dissolve in water?Ionic compounds on the other hand are formed when from the electrostatic attraction between oppositely charged ions. The electrons of an ion are transferred to another atom. The atom that loses an electron becomes a positively charged ion while the one that gains the electrons becomes the negatively charged ion.
Why do covalent compounds dissolve in acetone?
Napthol, C3H6O, as covalent compounds and acetone ,(CH3)2CO,as an organic solvent, Napthol is soluble in it because they are made of organic elements, which they attract they particles of the solute by the particles of the solvent been easier to break down into a solution.
Why do metals conduct electricity?
Metals conduct electricity because their atoms and outer electrons are not kept with a specific atomic nucleus and due to the orientation of the atoms in the pure metals or molecules to mixed metal. There are a lot of electrons moving that are liberated to be in motion in response to an electric voltage, a greater uniformity of atomic orientation, the greater conductivity.
The metal atoms have many free electrons in their orbits (many electrons surrounding the atom) and these electrons are going to conduct electrical current because it has unfilled spaces in the valence band energy,
Staying in its original energy band, this movement of electrons contributing to the establishment of an electric current.
Why do the covalent compounds NOT conduct electricity?
Covalent compounds do not conduct electricity because they don't have free electrons and no ions.
Why do ionic compounds have such a high boiling points?
The ionic compounds have electrostatic attraction and a crystal lattice between them. This creates a strong bond, which can only be separated by high temperatures, that melt the crystal so the particles can separate.
Why do metals have such high boiling points?There is NO IONIC BONDING in metals. It is metallic bonding, which is something different.
Metallic bonding involves a "sea of electrons" that extend over the metal atoms. There are strong forces of attraction between these electrons and the positive nucleus of the atoms, which are relatively difficult to overcome. This explains the high melting and boiling points of metals.
WORK DONE IN SAN FRANCISCO DE PAULA SCHOOL CHEMISTRY LAB
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