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  1. M

    Safe flea powder?

    It seems that you are basing your experimental powder on an existing labeled product and want to retro engineer it. While in grad school, I was witness to some high schoolers that my advisor had agreed to have us help with science fair ideas. One of the ideas used a video camera and T-maze to...
  2. M

    Airborne Spray that changes colour where Carbon Dioxide is present

    Ammonia will react with H2O and CO2 to make a white fog of ammonium carbonate or bicarbonate when all are present at appreciable quanties, but it is so hygroscopic that the xtals dissipate as small solution droplets that are essentially invisible. I would also steer clear of using aqueous...
  3. M

    Hints on this purification

    As hinted by chemistree, you should be talking about removing the byproduct of the EDC... We are also assuming that you (by some selectivity) did not get a complex mixture of the various benzoic esters of the sugar OH's, and the desired benzamide, that complicates things further (follow by TLC...
  4. M

    PH of a diluted solution

    A hint; take a look at the derivation of the HH equation and the simplifying assumptions that are made.... On the surface definition of a buffer, the pH is largely defined by pKa and has a broad largely unchanged pH over a range defined by the buffer's capacity. Dilution of the buffer only...
  5. M

    Hydrogen seperation from water

    The Wiki article describes PSA pretty well- it somewhat fits into the first method below for semipermeable membrane separation, but needs a driving force to release the adsorped molecules from the pores (usually atomic dimensioned channels in Xeolites). -semi-permeable membranes rely on pores...
  6. M

    Sheets of uranium?

    Reading this post's question of "home methods" in relation to radioactive materials, reminded me of an exercise that a senior scientist did with us in an industrial setting to sink home the dangers of radioactivity. A piece of paper, and a pen were handed to a gathering of us and each was told...
  7. M

    Medical Knee Injury

    I also have an injured knee that many years later was diagnosed via MRI as ACL tear and a torn meniscus injury. some thirty years later, it too also "goes out" and can prevent me from walking without a cane and a great deal of pain. Diagnosis is the first step... While in the appointment for...
  8. M

    Determining concentration of a particular substance in a solid?

    In short it isn't cheap and isn't easy... Cheap methods try to use a chemical reaction that is specific to the analyte and can be distinguished by vision (i.e. spectrophotometrically). Reactions that produce light and react enzymatically meet the issue of specific reaction and can be...
  9. M

    Determining concentration of a particular substance in a solid?

    For the item you are asking about, a weighed portion of the food (called an aliquot) is subjected to an extraction by a pure solvent to remove quantitatively the analyte (the acrylamide). A method that can detect the small amounts of the analyte is used to get a signal, and that is compared to a...
  10. M

    What does this notation mean?

    I believe Borek has it as these are the ways that superconductors and ceramics are often often described in "notation". Ceramics will be describing oxides with the noted molar composition of the XM, and superconductors will often use this , but have to describe the anionic components...
  11. M

    What does Nu- mean?

    You are getting it; I don't want to throw in a wrinkle but for polymerizations and for simple reactions that form only one covalent bond, the intermediate finds something else to act as a electrophile than another monomer unit. This reaction is known as a termination step in polymerization...
  12. M

    Question about silica

    silicon (the element) is generally reactive enough to become oxidized and change to silica, especially under geological conditions (don't expect to mine it or find it as the elemental ore). But it meets the definition of a material with specific molecular and crystalline properties known as mineral.
  13. M

    What does Nu- mean?

    Wiki spells it out in the beginning and the end of the article- the different nucleophilicity measures and equations aren't necessary for the concept. It does require a simple understanding of bond formation, and is narrowed to the covalent bonds formed with carbon in organic chemistry...
  14. M

    What does Nu- mean?

    In the insert drawing, the Nu- is water acting as a nucleophile and beginning the polymerization of the electrophilic double bond of the cyanoacrylate. The lone pair on H2O's oxygen acts as the partially negative charged nucleophile. The new partial negative charge is on the carbon alpha to the...
  15. M

    How to calculate the amount of CO2 needed to reduce the pH of a NaOH solution to 12.

    I suspect that if we were writing this as a problem to solve for a student, we would steer away from the complications of solubility and ionic strength by focusing on a weaker solution of NaOH, where the assumptions in the Henderson Hasselbach equation are followed. However, I do sometimes see...
  16. M

    Gas flow units MSCMD, KM^3 and SM^3x10

    Take a look back, and compare the size of pipes going into the gas meter and where the gas is going to get a reality check for your two versions.... If this is a low pressure gas main going to a burner, convert the volume per unit time to the linear velocity of gas through one meter of pipe...
  17. M

    How to calculate the amount of CO2 needed to reduce the pH of a NaOH solution to 12.

    A theoretical treatment of the role of ionic strength and activity coefficients starts with Debye-Huckel. .... the Wiki article on the following search terms... Debye-Huckel equation ; Debye-Huckel limiting law It seems you are motivated by curiosity- follow where the Henderson-...
  18. M

    Translucent, low-freezing point solution

    You might want to see literature on the Tyndall effect and how colloidal suspensions are stabilized. If you want the effect to be stable over a temperature range, you will have some difficulties since the colloid may aggregate by crystallization. Sols and gels are two variations on the theme...
  19. M

    Binders in SSP fertilizer

    I can understand if the reactor is a tube or other reactor than a tank; plugging with clay would be very bad indeed.... I thought however, that the fertilizer xtal slurry might be able to withstand the introduction of a clay slurry that is very dilute and held suspended with surfactant. The...
  20. M

    How to calculate the amount of CO2 needed to reduce the pH of a NaOH solution to 12.

    Borek means that the first step is reaction of two to one moles... 2NaOH + CO2 -> Na2CO3 + H2O (net eqn) Since this product is still largely a strong base in water it will be the predominant specie before the next amount of CO2 can start reacting to make the NaHCO3... Because of the high...
  21. M

    Dissolution of Inconel 617/Haynes 230

    If you have access to Perry's Chemical Engineering Handbook, you can find some of these exotic alloys and their corrosivity charts to many chemicals under a number of conditions. The inconels and Haynes alloys are made for Halogen acid resistance and are also resistant to oxidative conditions...
  22. M

    MEM protection of carbohydrates

    Remember that the sugar is a hemiacetal and the MEM and MOM ethers are acetals so there will be reactivity issues if the cleavage reactions are needed later. Most of the reactions on sugar OH's are based on reactions that can be run in water since the sugars are largely insoluble in other polar...
  23. M

    How to calculate flash point of mixture?

    One thing that makes this harder is whether the mixture will be 100% soluble or not- a two phase system is a strong possibility if even a slight amount of H2O contacts this, and then the vapor pressure exerted by the alcohol phase will rule the flashpoint as if the other was not even there. If...
  24. M

    Binders in SSP fertilizer

    I am sure you will find literature from bentonite producers, and it can be added as a slurry to bind or act as a final coat. It should also become somewhat hydrophobic if a small amount of biodegradable surfactant is used in formulating. Look in patent literature with appropriate boolean search...
  25. M

    UV degradation of PVC

    I have been looking at surface modification of PVC and other plastics to chemically alter their hydrophobicity and possibly allow coating with an inert and bio-passive coating- there is some literature that is pertinent to your question, as it covers free radical aqueous attack on the polymer...
  26. M

    Transparent paint carrier of electrical current

    Berkeman fat fingered ITO - it is Indium Tin Oxide when you start searching the internet- best purchased already fabricated on the glass or clear polymer, as it is not a paint and has to be sputtered and specially heat treated to sinter the nanoparticles. Indium makes it expensive, too. Also it...
  27. M

    THF evaporation under partial vacuum

    Just for grins I decide to take gen chem principles for ideal gasses; Raoult's Law and the combined ideal gas Laws and applied to the proposed set-up. Sigma Aldrich had a vapor pressure for pure THF at 20C of 143 torr, and Brown Chemistry the Central Science has vapor pressure for pure H2O as...
  28. M

    THF evaporation under partial vacuum

    If you are really looking to "study" a phenomena of colloid aggregation with such a setup, you will have to have to remember that you are looking at a process that is not in thermodynamic equilibrium and will have an exchange of heat from the "NP solution" to perform work across the valve of gas...
  29. M

    THF evaporation under partial vacuum

    You may still be running into the same disruptive forces that heating will create whether you use a partial vacuum and "no heating", or some heating... i.e. there will be gradients at the surface of the "solution" of THF, and water that will form thermal currents. Some combination of forces may...
  30. M

    Synthetic Methane

    Unless there is a reason that you cannot make separate electrodes and use DC in your electrolysis, you are better off isolating and collecting the hydrogen at the cathode and passing it to an anaerobic bioreactor for methanogenesis. It would be very sensitive to even traces of oxygen, so an...
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