Polarity and molecular shape lab

Title: Polarity and Molecular shape lab

Statement of the Problem:

* We are trying construct molecular shapes by looking at their Lewis structure and see if we could determine polarity.

* We found out that there was one resonance structure and a majority of the structures were indeed polar.

Hypothesis: The molecules with hydrogen and oxygen will not be polar due to their electro negativity with other elements.

Materials:

*we had small little tubes like structures that were our bonds, and we had small little round molecules which acted as our central atom.

Procedure:

* We had determine the Lewis structures of following molecules such as SF3 or H2O and the resonance structure SO3 (-2) we then constructed the molecules by the following Lewis structure we had just done for that individual molecule. We then looked at the structure and determined the polarity simply by looking at the structure. There was one resonance structure.

Results (Data):

Octahedral, 90 degree, non-polar, resonance





Tetrahedron, 90-109.5, degrees, non-polar, and non-resonance




Tetrahedron, 109.5 degrees, non-polar, non-resonance




T-Shaped, 120 degrees, polar, and non-resonance




Octahedral, 90 degrees, non-polar, and non-resonance



Tetrahedron, 180 degrees, non-polar, and non-resonance



Tetrahedron, 90-109.5 degrees, and polar and non-resonance


Tetrahedron, 109.5 degrees, non-polar, and non-resonance

Conclusions:

* Our hypothesis was somewhat rejected because there was some molecules with hydrogen that were polar.

We had all learned about how you can determine polarity just by looking at the structure and that we could make Lewis structures and create models by using there Lewis structure

Problems that could have occurred that our calculation of the electro negativity between the molecules so that would throw off our polarity accuracy.

By: James, Marco, Justin

Libby High School Chem lab blog

Title: Chromatography lab

Statement of the Problem:

* We are trying to answer or see what happens when solvents (such as water methanol isopropyl and hexon) separate black pigment and to figure out which solvent was more effective and what colors made up the black pigment.

* We found out that some were more polar others and there was one non-polar solvent.

Hypothesis:

* I hypothesis that hexone because will work well because its non polar and is a complex molecule.

Materials:

*Filter paper, Water, Hexon, isopropyl, methanol

*Black, red, green, yellow and blue markers

* Always wear goggles, do not inhale fumes, wear aprons wash hands after touching solvents.

Procedure:

* We first began with cutting 1cm *8cm strips of filter paper. Fold 1.5 cm from one end then. Then added 3 dots maximum of black marker on filter paper of creased line. Fill 4 holes of well plate with solvents such as water, hexon, isopropyl, and methanol and dipped the folded one of each filter paper end in each hole which contained the solvents then watch what happens for 30 minutes. Part step you repeat the process but instead with different colored markers and the only solvent is water.

Results (Data):

We found out that hypothesis wasn’t correct water was the best and fastest solvent because it’s a polar molecule and is the smallest of the solvent.

Conclusions:

* Our hypothesis is rejected because although hexon is a complex molecule it is non polar which did not allow the pigment to separate it.

We conclude that in order from best to worst: Water, methanol, isopropyl, hexon.

We learned about chromatography paper and how it can separate pigments.

A problem that could have occurred in this lab is that if the amount of solvent could change the rate of separation (of pigment)

Other problems that could have arose are things such as the filter paper was not working properly or maybe the solvents were not working to its full potential.

By: James, Marco, Justin