Tony Writes:

Hi, Im 14 years old and Chemistry really is my favorite subject in school,
and out. I had a question about CO2. Is it possible to break the bonds that
hold the CO2 molecules together?
ex.passes through something and carbon is trapped and air passes on?
Thanks a lot

Yes, it is possible to break the bonds that link the carbons to the oxygens in CO2. However, doing so is not easy, and outside the laboratory there is only one practical way to do this. CO2 is very stable and non-reactive, which is why it survives so long in our atmosphere, and contributes to global warming.

Scientists are working on a method for transforming carbon dioxide (CO2) into fuel, using catalysts and sunlight. However, it could be decades before this can be done on a large scale So there still really is only one way to convert large amounts of carbon dioxide (CO2) into oxygen (O2) – Photosynthesis.

Yep. What scientist have been able to do only with great difficulty – and usually with dangerous substances and expensive equipment – nature has been doing for a billion years with ease.

I know that “plant a tree” wasn’t the answer you were looking for, but photosynthesis is still the most efficient way to purify CO2, and it probably will remain so for another century or so.

Ghazal asks:

Dear AaC,

Hi, I am an engineering student, and I will be working on remediation of TCE using ZVI. My problem is that TCE is very volatile, so it’s hard to know how much of exactly I have, for example, if i wante a 50mg/l concentration, by the time is added, weight, how can i know how much i have in my vile ? I will also be using a GC, but the problem with that also is that i have to define concetrations for it, before i can give it an unknown concentration. ANother problem is that i need to make my viles are anaerobic as possible, but the ones that i have tend to contain a bubble of air in them as soon as put the cap on it. how can i avoid that?
thanks alot

Translation: Ghazal is (I believe) using a permeable reactive barrier (PRB) made of zero-valence Iron (ZVI) to reduce toxic Trichloroethylene (TCE) to non-toxic ethylene and water. In general, the system works by passing contaminated groundwater through the ZVI-PRB which de-chlorinates the TCE, so that only purified water passes through to the other side. He states that he will be using a gas chromatagraph (GC) to examine his samples before and after the remediation process in order to determine how effective the process is.

Solution
There are two ways to reduce the evaporation rate.

1. Lower the temperature. TCE freezes at -90 C. It is fairly easy to find a commercial freezer that can go down to -50 C or lower. If you place all of your equipment, including your sample of TCE in the freezer for about an hour, and then (quickly) take it to the lab and measure your sample, you should lose very little of your TCE due to evaporation. If you are in Canada, you can just go outside and do this.
2. Reduce the surface area. If you weigh your TCE into an extremely narrow glass tube, and then quickly cap it once you have your measured amount, you can assure minimal loss of TCE due to evaporation.

The only way to eliminate the problem of oxygen in your samples is to use a nitrogen blanket to displace the oxygen. Prepare your samples under a nitrogen blanket and then cap them so they are not contaminated with oxygen.

Benjamin Writes:

Dear AaC,

I am doing an assignment on removing certain inks and ethyl acetate seems to
do it best. I need to know whether i am able to dilute ethyl acetate in
water so as to reduce the quantity of purchase.

Ethyl Acetate is in a class of compounds known as Esters. Like most esters, Ethyl Acetate has a slight fruity smell. It is a non- to slightly polar molecule. Although it mixes well with other solvents, such as acetone, ethanol, and benzene, it is not terribly soluble in water.

According to the literature, ethyl acetate has only an 8.3% (by w/v) solubility in water, so you would not see a great savings if you were to mix some water into it. However, you may be able to mix in a less expensive solvent that is miscible with ethyl acetate and make a small savings that way.

Annie Asks:

Would you please explain in high detail what happens to blood when it is
heated/cooked?

Thank you.

Thanks for your question. I honestly don’t think I will be able to do this justice. This is more of a question for a biochemist or medical doctor. Blood is incredibly complex, and the behavior of various components depend on many many factors.

I can tell you what I know. Blood is made of about 55% plasma, and 45% red blood cells. The remaining 0% (its not actually 0, but it is a very small amount) consists of white blood cells, platelets, vitamins, minerals, and a host of other stuff.

Plasma is made of water and salts. There is a phenomenon called “boiling point elevation” which says that when solutes are added to water, the boiling point will increase. The boiling point of blood will be above the boiling point of water, but probably not by much – less than 1 degree centigrade, most likely.

So, as you heat the blood, you will hit the boiling point, and then it will remain at the boiling point, even if you continue to add heat. The blood will stay at the boiling temperature until all of the water has evaporated. What is left will be a thick sludge of red blood cells, salts, and other trace chemicals. If you continue to heat it, the temperature will increase, and the red blood cells will cook and eventually burn. Upon burning, they will give off CO2, CO, and a host of other organic byproducts. What is left will be nothing resembling blood, but will be a charred mass of ashy residue.

Diane Writes:

I just did an expperiment with two different versions of a gasoline
additive. I put a little bit of each version in a styrofoam cup and
suspended them each in a tall glass. One version ate through the styrofoam
in 3 days and the other version is still intact with no leakeage after day
6.

I don’t know the ingredients except to say that they are a combination of
200+ esters. Both cleaning and lubricating esters in a mineral oil medium.

One has a lesser grade mineral oil and the other has supposedly a higher
grade mineral oil and that is supposed to be the only difference.

Yet, they perform differenly in the styrofoam. This tells me something is
different with the formulation.

With this limited information, do you have any thoughts as to what could
make them perform differently?

The product that failed to eat through the styrofoam (a clearer version of
mienral oil)does not yield as good of gas mileage increase as the product
that did break down the styrofoam (A yelow version of the mineral oil.

Therefore, I am concerned that the clear version of the product is not
really the same formulation and may damage my engine. The product is put in
the gas tank as well as the crank case.

I would be grateful for any insight you can provide.

Thank you very much.

First of all, I wouldn’t worry about damage to your engine. Any product that is intended as a fuel or oil additive must pass EPA guidelines which state that the additive (1) must not damage the engine and (2) must not generate toxic emissions. If these products are made or sold by a reputable vendor based in the USA, then you should be safe.

The “styrofoam test” you conducted is probably not an accurate measure of the products’ cleaning power or engine-damaging potential. Since none of the engine parts, and none of the likely fuel contaminants, are likely to contain polystyrene, the test isn’t terribly useful. It does indicate that the two formulations are slightly different.

Ketones, such as acetone and MEK, will dissolve polystyrene very agressively (try putting a dab of nail polish in your styrofoam cup and watch it dissolve). Its possible that one of the formulations has a small amount of acetone or other ketone in it. However, if it took three days to break apart the cup, and acetone will eat through it in a matter of seconds, I would guess that there is a very very small amount in the formulation — not enough to help or damage your fuel efficiency.

What about your differing results in terms of gas mileage? Keep in mind that gas mileage is subject to a large number of variables. Your gas mileage can vary by 10 – 30% each time you measure it. Any apparent improvement in gas mileage may just be a result of normal variance.

Lastly, the AAA (American Automobile Association) has warned against any product that promises fuel savings. According to the AAA website:

“Some gasoline additives improve engine drivability by removing deposits from fuel injectors and other engine components, and others effectively deal with moisture in the fuel system,” says John Nielsen, Director of AAA’s Approved Auto Repair Network. “However, products whose primary claim is a major boost in fuel economy are another matter. Over the years, AAA has evaluated many such formulas, and has yet to discover one that can be proven to provide significant fuel-savings for motorists.”

Kenneth Asks:

I picked up a jar of an unknown (to me) substance that has unusual
properties. Color is clear. At around 70 F it flows like syrup. At about 90
F it appears as if it is set up. This can be cycled over and over. Substance
was in with a bunch of lab items. Any idea what this may be? What is the
property called where normal flow/temperature properties are reversed?

It won’t be possible for me to even guess what this substance is, even if I had it in front of me. We may be able to narrow it down to some possibilities if you can give any other information about it, especially in regards to its rheological properties. Try cooling the substance further to see if the viscosity continues to decrease. If it does, then you are onto something.

As for the terminology, I haven’t found anything, although I have some inquiries out in the lab near where I work. There are terms for how viscosity changes with changes in shear and also those that change with shear AND with time. But all of these terms assume a constant temperature.

• Newtonian Fluids: Viscosity does not change with shear or with time.
• Non-Newtonian Fluids: Viscosity is dependent on shear and/or time.
  • Time Independent: Viscosity changes with shear, but does not change over time.
    • Pseudoplastic: Shear thinning (the faster you mix it, the thinner it is)
    • Dilatant: Shear thickening (the faster you mix it, the thicker it is)
  • Time Dependent: Viscosity changes with shear and with time.
    • Thixotropic: Time thinning (the longer you mix it, the thinner it is)
    • Rheopectic: Time thickening (the longer you mix it, the thicker it is)

As I said, I have some inquiries out at the lab, and I will update this once I have some more information. If you are inclined to do some more experiments, please do, and post them here.

Thanks for the question!