3 questions a little late

Lately we have been flying through material. We have been introduced to the basics of equilibrium, and learned about rates and rate laws!!! In the past few weeks we have learned how EVERYTHING ties together in chemistry. We have also completed a test over the last unit in which we learned about lewis structures, molecular solids, etc. Next I am going to prep for the nerdiest thing I've ever done in my life…..chemical olympics, and also begin reviewing materials we have learned more.

Equilibrium

We began our intro into equilibrium with an explore lab! There were multiple test tubes. Some were in an ice bath, others in water over a hot plate, and some kept at room temperature.

Room Temperature

Hot Plate 

Ice Bath

There was an apparent difference in color in the test tubes, the darkest brown color was in the hot bath while the most colorless was in the ice bath. Each tube had different concentrations but it has the same substances; NO2 and N2O4.

The reaction in this process can be represented by an equation that is both exo and endothermic in that is both a forward and a reverse reaction: 2NO2 ⇌ N2O4

NO2 can be accounted for the brownish orangeish tint of color in the test tubes. It was visible that some test tubes had more of a concentration of NO2 than the rest, for example the test tube in the hot bath. As seen from the picture, it had the deepest brown color. However if one were to move this test tube from the hot bath to the cold bath of water, the test tube would become less colorful. This is because more colorless N204 would be produced. The production of N2O4 is favored by an exothermic process, causing a shift in equilibrium so that homeostasis will be maintained. This causes a faster rate of the forward reaction therefore producing more N2O4.

Now if  a cold tube was placed in a hot bath the effects would then be opposite. The heat would be absorbed therefore making the reaction endothermic and speeding up the rate of a reverse reaction. There would also be the brown/ orange color produced. 

The test tube at room temperature is takin it easy, and has no change in shifts for equilibrium and the rates of the reaction are equal.

This whole explore lab can be explained by LeChatelier's principle in which a system will shift in order to achieve equilibrium. 

Classification of a Solid!

We completed a Classification of Solids Lab in order to classify and identify common properties of a solid substance by uses techniques to check MP, conductivity, and solubility. With the results from these tests, we were able to fulfill the purpose of the lab.

The process began with placing; MgO, CoCl2, phenyl saline acid, benzoic acid, KBr, Charcoal, Sand, Fe, and Zn in plastic well plates.

First we examined the crystal structure of each solid. We then put a bit of each solid into different test tubes, and held them over bunsen burners measuring the melting point of the substances over a scale from less than 100 to greater than 300 degrees. Next we tested the solubility of each substance. We placed water, ethanol, and cyclohexane in a different sample of each substance. If the solid was completely dissolved we then tested for conductivity. Our test resulted in only two substances being conductive those being; KBr and CoCl2.

Our classification of the solids results were:

• MgO, CoCl2, and KBr for IONIC solids
• Phenyl Saline and Benzoic Acid for MOLECULAR
• Iron and Zinc are METALS
• Charcoal and sand as NETWORK solids

Questions:

1a. If solids are classified ionic solids would be soluble in water.
1c. Molecular solids would be soluble in organic solvents.
1d. Metals would conduct electricity when under pressure.
1e. Molecular solids would be slightly soluble in water and slightly conductive in that solution.

2. Due to a solid's slight electrical conductivity, white appearance, and MP at 80 degrees the solid would be classified as a molecular solid.

3. A network solid would be the classification of a high 1000 degree MP, insolubility and inability to conduct electricity. It would not be a metal seeing that if it was, it would be conductive.

4. K-metal, CaCO3-ionic solid, C8H18-molecular solid, HCL-ionic solid.

5a. Network solids are generally insoluble in water.
b.  Metals are generally ductile and malleable.
c.  Ionic solids generally nonvolatile.

This lab went well in comparison to the other labs we have completed. I really enjoyed it until I felt like I was going to pass out from the mixtures of smells, in particular the odor from the cyclohexane. :) In addition to making me light headed, the cyclohexane ruined the well plates by kind of decomposing the plastic… sorry :)

3 Questions!

Question 1&2:
Soo, I can't remember which week the answers to these questions are supposed to be from, sorry… These weeks have been a blur in which we've completed multiple labs, learned new things and stuff like that. :) We continued building on to molecular geometry, eventually learning about hybridization, formal charge, and so on. We continued on and made our very first drug which was aspirin, and have recently completed a classification of solids explore lab. 
Question 3:
NOW, I am reviewing because I desperately need to requiz to improve my grade and understanding of the material.

Soap&Pepper

INTERmolecular forces occur between molecules. Different variations of these molecules include;

London Dispersion forces: imfs that occur between non-polar molecules due to attractions of opposite charges. These forces result in instantaneous dipole movements.

Ion-Dipole & Dipole-Dipole: caused by attractions between positive and negative poles in a polar compound.

Hydrogen bonding: dipole forces with a polar hydrogen atom

One substance in particular has many of these forces at work! H2O has both London dispersion forces and hydrogen bonding: 

Why review IMFs? To help explain the explore lab we recently completed! We added pepper on top of water in a cup, i covered my finger with soap and as I placed my finger in the water, the pepper quickly dispersed. As you can tell by the video we are entertained easily :) 

The cause of this is likely to be explained by a dipole-dipole interaction from the soap! Soap is what is called a "surfactant" meaning it has the ability to lower the surfaces tension between two liquids or a liquid and a solid! As I stuck my soap covered finger in the water, it caused a rearrangement in the H20 molecules thus resulting in a movement across the water causing the pepper to outline the edge of  the cup.

Tres questiones

We've taken another quiz and completed an AP styled test, yay!

Recently I've learned that reviewing is key and I desperately need to do this.

Now I will review my materials so i can become an expert at chem like Walter White :)

GRAS Food Dyes

The industry of processed foods and food additives has grown immensely. The FDA regulates these additives in order to deem them safe or unsafe. Those additives surpassing regulations are entitled "GRAS" by the FDA. Gras is an acronym for "generally regarded as safe." "Under sections 201 and 409 of the Federal Food, Drug, and Cosmetic Act any substance that is intentionally added to food is a food additive…generally recognized among qualified experts as having been shown to be adequately safe…" There are currently 7 synthetic food dyes approved and recognized by the Food, Drug, and Cosmetic Act. These food dyes serve no purpose but to be aesthetically pleasing. More specifically these food dyes are used for; coloring loss, "making food more fun", and enhancing natural color. At what cost are these foods made "more fun?" 

The Current 7 Food Dyes

Blue No.1(Briliant Blue) 
Often found in: dairy products, jellies, icings, etc.
Hazards: can cause allergic reaction in preexisting conditions of asthma.
Chemistry Aspect: 

Blue No. 2 (Indigotine)

Often found in: ice cream, sweets, baked goods, etc. 

Hazards: may cause vomitting, high blood pressure, skin rashes, breathing problems, or allergic reactions

Chemistry Aspect: 

Green No.3 (Fast Green) 

Often found in: peas, veggies, fish, etc. 

Hazards: poorly absorbed by intestines resulting in irritation in digestion tract; as well as irritation in skin, eyes, and respiratory system. 

Chemistry Aspect: 

Red No. 3 (Erythosine) 

Often found in: candies, condiments, etc. 

Hazards:studies show it may cause thyroid tumors, chromosomal damage, and breast carcinogenesis 

Chemistry Aspect:

Red No. 40 

Often found in: cotton candy, tattoo ink, children's meds., etc

Hazards: hyperactivity, also been linked to cancer in mice 

Chemistry Aspect: 

Yellow No. 5 (Tartrazine)

Often found in: mustard, gum, yogurt, cake mixes, etc.

Hazards: induces asthma attacks, hives, itching, restlessness, allergic reactions including; migraines, blurred vision, purple skin patches. 

Chemistry Aspect: 

Yellow No. 6 (Sunset Yellow)

Often found in:  hot chocolate mix, soup, orange squash, etc. 

Hazards:  allergic reactions or gastric problems, vomiting, rash or swelling of skin

Chemistry Aspect: 

These don't look so appetizing now, do they?

Sources:

http://www.iatp.org/files/421_2_105204.pdf

http://www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm094211.htm#types

http://www.fda.gov/ForIndustry/ColorAdditives/RegulatoryProcessHistoricalPerspectives/

http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/SCOGS/default.htm