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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

    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...
  6. 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...
  7. 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...
  8. 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...
  9. 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.
  10. 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...
  11. 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...
  12. 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...
  13. 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-...
  14. 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...
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...
  21. 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...
  22. 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...
  23. M

    How do I turn sodium acetate trihydrate into sodium acetate anhydrous and vice versa?

    If you fuse (i.e melt) the hydrated sodium acetate, you may be able to boil away the the waters of hydration at temperatures well above the melt temp. The anhydrous salt according to Wiki has a melt point of 324C vs the trihydrate of 58C. additionally Wiki has the decomposition (i.e loss of...
  24. M

    Silver and Aluminum

    For a selective dissolution of aluminum leaving the silver, I might try using hot aqueous 10% NaOH. Raney nickel is made by using the NaOH reaction on an aluminum nickel alloy having at least 10% aluminum, leaving a porous nickel sponge that contains adsorbed hydrogen from the reaction of Al...
  25. M

    Flouride salt safety issues? (high temperature)

    One difference is that nuclear plant engineers can afford to use exotic corrosion resistant alloys for containment. You platens in your DSC TGA may not be up to it for the testing with Fluoride melts. If I understand your premise, it is that you are looking for safety features that would...
  26. M

    Polymerisation of diol?

    This extremely important, since only the simplest case of the diols existing on the same carbon are readily polymerized to poly acetals (geminal diol). The simplest is polyformaldehyde, a white powder that is poorly soluble in water with reaction to depolymerize to a formaldehyde solution. One...
  27. M

    What iron-salts will dissolve in water?

    In this media one is using the citrate as a complexing agent that keeps the Fe in solution and doesn't cause the required phosphate nutrient to precipitate out insoluble iron phosphates. The solid waste may be depleting other nutrients than iron from your media. Have you some idea of the...
  28. M

    Aminophenol with R-COCl

    The amino group is considered more nucleophilic to attacking the acyl group and displacing chloride, than a phenolic hydroxyl. The phenolate anion will not be present in enough quantity to interefere (it is somewhat better nucleophile than free phenol hydroxyl). Of the phenolate ester that is...
  29. M

    NMR versus GC/MS, HPLC/GC, HCLtitration, meltingpoint test

    In my experience, a starting material that was involved in manufacturing an analgesic related to ibuprofen, was tested for extreme purity by melting point/freezing point. GC was available, but wasn't sensitive enough and the impurity was not completely resolved using capillary columns. It was an...
  30. M

    Styrene Maleic Anhydride - Bond Angles and Lengths

    Styrene and maleic anhydride can be copolymerized in a number of ways that greatly change the resulting polymer. Random polymerization by radical mechanisms is probably the most common, and takes place in head to tail fashion, predominately about the alkene double bonds, to make the sp3...
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