Tran,+Steve

HF reacts with rust to remove it. Acids form when charged hydrogen atoms bond with a nonmetal. Strong acids have weak bonds with the hydrogen, whereas weak bonds have strong bonds to the hydrogen. Fluoride has a strong electronegativity and will retain the electron of the hydrogen, when separated, so the hydrogen is just a proton when in an aqueous medium. As a whole, HF doesn't carry a charge so it goes past the skin. The fluoride ion wants electrons so it bonds with ionically positive ions in our bodies. The hydrogen ion, which was separated, from the fluoride, binds to negatively charged ions in our bodies like enzymes that regulate Ph. Calcium is a positive ion in our body that fluoride can bind to.

Greek Article The Greek prefixes are the basis of many elemental names. Their numerical prefixes are used for naming different chemical compounds like the molecular compounds. Hypo, and per are also Greek prefixes that tells how many oxygen are in an ion like ClO- and ClO4-. What was interesting was that hydro wasn’t the basic root word, but rather hydro was based on another even older word, hudoor. It seems that Greek and Latin origin words are used in a mix sometimes in chemistry, like hexadentate and nona-. I always thought that Latin was the base language of science but many Greek words are the base.

Energy Article: I read the article on solar power called, Solar Power Lightens Up with Thin-Film Technology. In the article it stated that the new thin film solar panels convert 19.9 percent of the sun's energy to electricity, and it is half the cost of conventional solar panels. I find that even though its more efficient and cost effective, it would still require large amounts of area to put these things up. Also, the article stated that these figures came from perfectly made, chemical restricted, prototypes. Mass production of these are said to cut the efficiency of the solar panels in half. This I found surprising, I never realized that under mass production of some of our technology, the efficiency of the product went down. I assumed that with new technology, the factories could make perfect copies of the thin film solar panels. In accordance to the article,something that is pertinent to the class is the statistics that the sun gives off enough KJ to the Earth in one hour to run the entire world for a year. That is a large difference that if it could be used would mean an enormous energy surplus from the sun. The article talks about integrating this thin film technology into construction material so that our roofs are solar panels, but I don't believe people will go for this if the cost of the integrated building material is more costly than the power savings you'd get from it.

Steve, Good Post! Solar panels are continuing to improve. MW

Polymers Well I learned that rubber is not so different from chewing gum, other than the fact that it is vulcanized. I never knew that without vulcanization the rubber would be a thick liquid. I also did not know rubber bands were in the category of vulcanized rubber, I had assumed that vulcanized rubber was tough, hard rubber like on tires, but not the stretchy rubber bands at home. Polymers remind me of the protein tangles when they are vulcanized. I also learned that rubber apparently gathers and keeps heat, I never thought of rubber as a good absorber of heat considering that rubber stuff like hot hands are used to protect people from heat. Plus, what was interesting to know was that the green color causes the best absorption of sunlight, which might be why plants are green. I think the company probably sells disinfectant for the field to take care of the bacteria issue.

Steve, Good comments. I like your vulcanization observations. Tires are highly vulcanized and are often a copolymer not just "rubber". MW

Oil and Water Three things that I knew from the article was that water had a stronger dipole-dipole intermolecular force called a hydrogen bond. I also knew that water was polar and oil was non polar. Also, oil molecules are capable of London dispersion forces, since all things have it. Something I learned that was really new was that oil is more attracted to water than itself. I also learned that the reason oil and water don't mix is because water wants to stick to itself more than oil and not that they both don't like each other. I learned that the reason why oil spreads out over the water's surface is that the oil wants to maximize water contact, which is defiantly not an action of repulsion. What I found really interesting is the comparison of how water, a polar, acts on a non polar surface by sticking together into droplets, while a non polar acts on a polar surface by spreading over lot that surface. I would have thought that the reactions would be the same for both ways.

Steve, Yes that last bit was somewhat counterintuitive. Well done! MW

Salting the Roads I found quiet interesting that to freeze a solution, you have to continue dropping the temperature because as you freeze the pure solvent, the solute concentration increases. I would think that after a while, when only the solute is left, that it would be considered both frozen then. If I hadn't read this article I wouldn't have realized that the solid ice crystal doesn't really want to react with the salt because that would ruin the crystal lattice structure. In fact when the solution freezes, it tries to get rid of the salt. The only reason it does react is because the surface molecules are more "mobile". This part confused me. Are they saying that the surface molecules are somehow different than the other molecules? I think that maybe the surface ones are only attached on one side rather than attached from all sides, so that is why it is more loosely held. I'm not too sure that I would want the use of sugary syrup being sprayed on the roads during the winter. I would think that would be rather unpleasant to walk in, but I guess an addition of sugar will also serve as another particle to increase "i" value.

Steve, I think your instincts are sound as far as answering your own questions. I agree with you on the sugar thing. Plus I would think it would attract animals! 5 big stars! MW

Hand Warmers One of the three things that I already knew from the article is that by increasing the surface area of the reactants, the reactions can occur faster. Another thing that I already knew was that some plastics were semipermeable. If you go to your local butcher and ask for a slice of meat, sometimes the outside of the bag they put the meat in, feels wet and greasy even though you think it should keep that stuff in. I also knew that if you increase the oxygen concentration the reaction would happen faster. One of the three things that were new to me was the fact that different materials seem to allow more oxygen through that others. I do not know if they mean rate at which the oxygen comes into the pouch or the actual amount of oxygen because I would think after so much moles of oxygen goes into the bag, once that reaches equilibrium with the outside oxygen, then that would be the limit of the oxygen for a hand warmer. Another thing I did not know was that reusable hand warmers used the warm puppy supersaturated trick. I would have thought that it would be hard to keep those things stable and in liquid form until the right time of use. I also learned that the hand warmers used a iron rusting reaction, which reminds me of the thermite reaction. I wonder how the two are different in terms of what makes one hotter than the other.

Steve, I think the perforations limit the rate of oxygen effusion so that limits the rate. Thermite uses Iron oxide and aluminum powder. - much more exothermic! 5 stars! MW

Maple Syrup One of the things that I learned about maple syrup is that it is made up of mostly sucrose molecules, which is actually glucose and fructose joined together, rather than just a variation of a carbon ring. I also learned that cellulose has a similar structure to the sucrose molecule, and that sucrose is used to make cellulose. I thought cellulose was a tough plant matter used as structuring in plants, which is surprising to know it is made of similar stuff as soluble sugar. A third thing I learned is that syrup is actually acidic from acids like oxalic acid and amino acids. I wouldn't have thought of maple sugar as acidic, then again according to a pH chart, soda has just as much acidity as maple syrup, but from bicarbonates. I knew that osmosis is where the less concentrated solution tries to go to the more concentrated side of a solution if a semipermeable membrane is between them, so reverse osmosis is just sending the water through a filter to leave the syrup. I also knew that as the concentration of particles in a solution gets higher the boiling point gets higher, which is why the water in the syrup gets harder and harder to boil the more you boil. I also knew that as the concentration of a solution goes up, there is a higher chance of collisions and reactions that can take place, meaning more compounds that give the syrup its flavor can form. Another thing I knew is that some solutions, when they are heated, will increase solubility, but when cooled down the saturation point goes down causing the syrup sand.

Steve, Very thorough! BTW soda acidity is generated from carbon dioxide and added acids like phosphoric acid, not bicarbonates which are actually alkaline. 5 stars. MW

Flaking Away One thing I knew was that rusting was a reduction and a oxidation reaction all in one because there cannot be one without the other. Another thing I knew was that car companies use electricity to paint the entire frame of a car today in order to prevent rusting. There was a Toyota recall on Tacoma trucks that were made without paint on their frames to protect it from rusting. A third thing that I knew was that steel is made from iron and carbon, but I didn't know that silicon was used in steel. I wonder if that silicon helps or stops rust because it is a semiconductor. One thing I did not know was that iron was a good anode and that the other metals in steel are good cathodes. Does carbon act as an electrode in rusting in any way? They are basically setting up for the iron to oxidize. Another thing that I didn't realize was that with extra electrons, oxygen and water could be reduced into hydroxide. I also didn't know that chloride formed a complex ion with iron, making it dissolve faster. I would think that the salt in the water acts as a salt bridge to neutralize the electrical charge formed by the redox reaction. A third thing that I did not know that rusting was such a big problem that cost $276 billion a year! That seems a bit large for rusting, considering you do not hear it mentioned on the news or in political issues.

Steve, People behind the scenes work very hard to prevent or delay rusting. It doesn't play well in the press though since it's not that exciting to watch. 5 stars!! MW