Daily Post 30/4/12

On your blog describe how the following molecules stick to a positive surface. Describe two things: 1. How much do they stick in relation to each other, and 2. How is it aligned.

NH₃, BH₃, CH₄, CO, N₂, O₂, and CO₂.

(Image created by me)

As shown by the image, NH₃ and CO have a strong particle charge, and BH₃, CH₄, N₂, O₂, and CO₂ have a weak particle charge.

Also, list which molecules of this group you would expect to dissolve in water.

CO, NH₃

Daily Post 25/4/12

Draw / Explain pictures of hot air and cold air. Which one is more dense? Which one is moving faster?















(Images created by me)

Which one is more dense?
If pressure is held constant, hot air will have a larger volume than cold air. Assuming that there is the same amount of molecules of hot and cold air, the density of hot air will be less than the density of cold air. Density = kg/m3

Which is moving more?
Hot air is moving more than cold air because temperature acts like a speedometer. The higher the temperature, the faster the speed of the molecules.

Which is more dense: Dry air or Humid air? Why?

At the molecular level and at the same temperature, dry air is more dense than humid air because dry air contains heavier molecules. If one sample was taken of each air, both samples would have the same amount of molecules in them. The water molecules in the humid air would have replaced some of the nitrogen or oxygen molecules. As a result, humid air would be less dense because waters molecules are lighter than nitrogen and oxygen molecules.

Daily Post 13/4/12

The shapes of molecules are very important in their reactivity with the human body.  Post a 3D image of caffeine and cocaine and show how the shapes of these two molecules are quite similar.

Caffeine: C₈H₁₀N₄O₂

Cocaine: C₁₇H₂₁NO₄

Observation

From each chemical formula, each molecule uses the same type of atoms to create both molecules.

April 13

Daily Post 12/4/12

Energy content (density) of materials is a very important characteristic to meet our energy demands. Use thermodynamic concepts to rank the energy density of CNG (compressed natural gas), ethanol, gasoline and Li ion batteries.

                Material              MJ/Kg          MJ/L

1.       CNG                        53.6              9

2.       Gasoline                  47.2             34

3.       Ethanol                    30                24

4.       Li ion batteries          0.72             0.9-2.23

Source: http://en.wikipedia.org/wiki/Energy_density

Asprin

Place on your blog the answers and steps (process) to this student's aspirin lab questions from Organic Chemistry I:
   "I started with 2.0 g of salicylic acid and 5 g of acetic anhydride and I got 2.1 g of acetylsalicylic acid (aspirin).  What is my theoretical yield and my percent yield?"

	C7H6O3        +     C4H6O3        ->    C9H8O4       +  HC2H3O2
Grams	2.0g	5.0g	2.612g
Molar mass	138.12	102.09	180.15
Moles	.0145	.0490	.0145
Limiting reagent	x

2.0g of C₇H₆O₃  x         1 moles   _ =  .0145 moles of  C₇H₆O₃

                               138.12g

5.0g of C₄H₆O₃  x         1 moles   _ =  .0490 moles of  C₄H₆O₃

                               102.09g

.0145 moles of C₉H₈O₄  x      180.15g   _ =  2.612g of C₉H₈O₄

                                         Moles

Theoretical yield of C₉H₈O₄ is 2.612g

Percent yield is 2.1g / 2.612g x100 = 80.4%



March 23

Limiting Reagents

Today in class we discussed limiting reagents.  On your blog, describe the process you used to determine how many quarter pound hamburgers could be made.

To determine how many quarter pound hamburgers I could make, I used a recipe (unit converter) and an order list (supplies) to begin.  From there, I found the limiting factor by multiplying the recipe and the order list together.  Some of the ingredients on the recipe required more than one of that ingredient (2 pieces of cheese) to create a quarter pounder.  From the list I created, I looked for the smallest number and concluded that the lowest number was the limiting factor.

For the following reaction, determine which reagent is limiting and how much of the product can be made:

Begin with 8.5 g of hydrogen (H₂) and 40.2 g of oxygen (O₂).

Post you answer and process for solving this question.

	2H2                       +                     O2                       →                   2H2O
Grams	8.5g	40.2g	22.61g
Molar Mass	2.016	32.0	18
Moles	4.216	1.256	1.256
LR	2.11	1.256 x

8.5g of H₂  x          1 mole   _  = 4.216 moles of H₂

       2.016g

40.2g of O₂  x         1 mole   _  = 1.256 moles of O₂

         32.0g

The limiting reactant is Oxygen

1.256 moles of H₂O  x        18g   _ = 22.61g of H₂O

                                     Moles

Daily Post 29/2/12

On your blog post practical examples of the types of reactions we are studying in class.  Perhaps these are reactions related to your career interest, or just of interest!

Acid-Base reaction

HCl + NaOH -> H₂O + NaCl

The combination of Hydrochloric acid and Sodium Hydroxide can be useful when stomach acid levels are higher than normal and need to be equalized.

PPT reaction

2Al(OH)₃ + 3H₂SO₄ -> Al₂(SO₄)₃ + 6H₂O

I find this reaction interesting because the Aluminum Hydroxide purifies the water molecules.

REDOX reaction

Fe +2 H₂O -> Fe(OH)₂ + 2H

In this reaction, the iron is being oxidized by the water molecules to form rust. I can relate this reaction to winter driving because when the snow sticks to the car causing oxidation to occur.

Gas forming reaction

CH₄ + H₂O -> CO_(g) + H_{2 (g)}

The combination between methane and steam is used to produce hydrogen gas and carbon monoxide. I find this reaction interesting because hydrogen in gaseous form can be used for multiple applications. 

Examples to include: PPT, REDOX, gas forming, and acid-base. Post the balanced reaction and why it is of interest to you.

Daily Post 24/2/12

What surprised me related to the lab yesterday?

Something that surprised me in the lab yesterday was when the reaction between the H₂SO₄ and the NaOH because of the change in temperature. Also when mixing two liquids together, a solid forms.

 What was an observation that led you to think a chemical reaction occurred?

I knew that a chemical reaction occurred when the mixture changed colors, state, and changed temperature.

Which reactions produced different product(s) states?

Combination between BaCl₂ and FeSO₄, FeSO₄ and K₃[Fe(CN)₆], NaCl and AgNO₃, and H₂SO₄ and NaOH.

An observation I made is different product states occur when mixing soluble compounds.

Describe salt going into water

As the salt hits the water, the atoms separate from each other and float freely around in the water. As more salt is added to the water, the mixture becomes saturated with salt. When the saturation limit has been reached, the extra salt lays at the bottom of the container in a dynamic state. Depending on the solubility of the salt will affect how much the salt will dissolve in the water.

Write a chemical equation for the above observation

NaCl_(s) + H₂O_(l) -> H₂O_(l) + Na⁺_(aq) + Cl^-_(aq)

Daily Post 15/2/12

What were today's two main topics?
Naming ionic compounds
Coulombs law and melting points of compounds

Look at food or product labels in and around your home. Post on your blog (name and formula) 5 ionic compounds that you found, and list the common product in which they are contained.
Sodium aluminum phosphate [ Na₃Al₂H₁₅(PO₄)₈ ]-Flour tortillas
Aluminum Bicarbonate [Al(HCO₃)₃]-Goldfish crackers
Sodium Bicarbonate [Na(HCO₃)]-Lay’s potato chips
Monocalcium phosphate [CaPO₄]-Cereal bar
Calcium Chloride [CaCl]-Canned tomatoes

Explain why ionic compounds tend to have high melting points.
Using Coulomb’s law (F=K*q₁q₂/r²) we find that as the charge of the ionic compound increases, the melting point of the compound increases.  Also using Coulomb’s law, we discover that as the size of the ionic compound increases, the melting point decreases.  From this observation, we can conclude that the force between atoms varies directly with the melting point of the compound.

Daily Post 8/2/12

What were the main topics covered in class today?
Structure of atoms

Describe the structure of an atom.
A structure of an atom contains a nucleus consisting of protons and neutrons. Around the nucleus of the nucleus is a “cloud” of electrons. 

Explain the location and behavior of electrons.
Electrons behave like a cloud in which they appear at a random point around the nucleus and in difference layers-or rings-(depending on the atom).

Comments:
When the topic about the table being touched and what interactions were taking place, I failed to mention the phenomenon that there is a layer of “ice” at room temperature laying on the surface of the table. So according to the research from Caltech, there is a layer of ice between my finger and the table I am attempting to touch.  

Daily Post 3/2/12

What are the four fundamental forces in our universe? List the two that we most commonly feel and experience every day.

The four fundamental forces in the universe are strong nuclear force, weak nuclear force, electrostatic force, and gravity. The two forces that we feel and experience every day are:

-Gravity
-Electrostatic force

Explain a situation (list liquid examples and order) in which two liquids of different densities form two layers.

The example that was given in class was the solution of oil and water. Because oil is insoluble, both liquids don’t mix with each other. Another example in everyday life is vinaigrette. This is as solution of oil and vinegar in which both liquids aren’t able to be mixed with each other. Going back to the first example, the layer order of the liquid in a beaker would be:

-Oil (on top)                0.8 g/cm³
-Water (on bottom)     1.0 g/cm³

The layer order for the vinaigrette would be:
-Olive oil                     0.92 g/cm³
-Vinegar                      1.01 g/cm³

Explain a situation in which two liquids of different densities form one layers.
            An example of a solution containing two different liquid densities is a cocktail (as mentioned in class). When the liquids are poured into a glass, they need to be agitated in order for both liquids to reach equilibrium and form one layer.

List the density of osmium, lead, and aluminum.
-Os: 22.59 g/cm³
-Pb: 11.34 g/cm³
-Al: 2.70 g/cm³

What questions/comments do you have?

Related to the four fundamental forces in the universe, I remember from high school learning that three of the forces (strong and weak nuclear, and electrostatic forces) can be related to each other, however, gravity cannot. If physicists were able to relate gravity to the three other forces, they would be able to complete the Theory of everything, which would allow us to understand of everything in our universe and how it began.

For future reference:
-Strong nuclear force: gluons
-Weak nuclear force: bosons
-Electrostatic: photons
-Gravity: gravitons

Daily Post 30/1/12

What are today's Main Topics?
-Chap. 1: temperature, states of matter, and density.

Describe the difference between an absolute scale and a relative scale?
The difference between absolute scale and relative scale is that the absolute scale refers to the temperature in which molecular motion begins to occur (0K) and relative scale refers to the molecular motion that we are familiar with (70°F).

What questions do you have? Further explanation
-Why didn’t we cover Bose-Einstein condensate and Plasma?

What things do you wonder about? Think/career/connection
-Possibility of achieving temperatures below absolute zero; benefits of using materials close to absolute zero; when can a solid, liquid, and gas coexist.

Daily Post 27/1/12

What are three topics that we covered in class today?
-Chemical/Physical changes
-How to use the periodic table
-Introduction to atoms and molecules 

What did you find interesting in class today?
The topic I found most interesting during class was the balloon experiment because it combined the knowledge I already knew and added-on to it.

List a few ways that we identify a chemical reaction has occurred.
During the balloon experiment, the oxygen molecules reacted with the hydrogen atoms. The evidence of this happening is an explosion when the balloon was heated with the candle.

Write a question or comment that you have about the material that we covered today.
Most of the material covered during class I had previous knowledge in as well as, but it acted as a refresher for me.

How Chemistry relates to our Career

1.       Why is chemistry important to your career?

The definition of chemistry is “The science that deals with the composition and properties of substances and various elementary forms of matter.” The importance of chemistry for my career is that it involves the process of how atoms and molecules interact with each other both at the atomic and larger scale. Chemistry also can be used for creating nanomaterials to be applied as a coating on consumer products.

Sources: http://dictionary.reference.com/browse/chemistry

2.       Select a molecule that will be important in your career and describe the uses and characteristics of this molecule.

Molecule: Titania

Applications:

-Used for coating materials/particles such as Carbon nanotubes and Quantum dots
-Can be used as a sensor to monitor the amount of oxygen in the air.
-When Titania is used in photovoltaic cells, it can increase the efficiency of electrolytic splitting between hydrogen and oxygen atoms in water.
-When applied in a thin coat to a material, Titania exhibits self-cleaning and disinfecting properties when exposed to UV light.

Characteristics:

-Density: 4 g/cm³
-White color
-Molecular name: TiO₂
-Molar mass: 79.87 g/mole
-Melting point: 1843 °C
-Boiling point: 2972 °C

Source: http://www.azom.com/article.aspx?ArticleID=1179; http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/48_2_New%20York_10-03_0584.pdf;