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Everything posted by Borek

  1. Go to chemspider and search for the formula - this yields list of a known compounds, not every possible one (whether it exists or not). And some compounds that look OK on paper don't exist in reality.
  2. Try. I don't see why not, I believe around 200 deg C is enough to dry it. I can be wrong though. Note: if it absorbed enough water it will melt first (actually it will not melt, but it will dissolve in its own hydration water). You may have to wait several hours before it dries out. Question is if you need it perfectly dry, could be partial drying will be enough to make it possible to prepare a powder.
  3. Sodium chloride is either solid - when it is solid, or aqueous - when it is dissolved. "Just sodium chloride" doesn't say anything about whether it is solid or aqueous.
  4. 5 second googling: http://www.ncbi.nlm.nih.gov/pubmed/15653512 Even if not perfect, it is a starting point.
  5. Basically that's what chemical warfare is about. Wikipedia has a List_of_chemical_warfare_agents
  6. M is usually used for molarity, not molality, so it can be a little bit confusing here. Borek
  7. Check this solution preparation example. Especially operating procedure at the bottom of the page. Borek -- concentration conversion
  8. Try this limiting reagent lecture. Borek -- equation balancer and stoichiometry calculator
  9. C1V1 = C2V2 - yes, but 1 means NaOH solution and 2 means HCl solution. The equation looks the same as in teh case of dilution, but it is not the same. So what you have is 18.32ml*0.08045M=25ml*C(HCl). Solve for C(HCl). Looks to me like your error was about 0.55%. Borek -- Stoichiometry calculator www.pH-meter.info/pH-electrode
  10. See water ion product to check how water dissociation constant changes with temperature. In general no ion can facilitate water dissociation, however, if you dissolve an inert salt increasing ionic strength of the solution, you will observe changes in the water dissociation. But this effect is universal, it is not limitied just to water dissociation. See ionic strength and activity coefficients lecture for details.
  11. Exponentially, just like Gauss curve. In fact Gauss curve is a solution of diffusion equation for the initial concentration being 1 at x=0 and 0 elsewhere. Borek -- Stoichiometry calculator www.pH-meter.info/pH-electrode
  12. Download BATE and play with titration curves to get familar with them Program is commercial but there is a 30-day free trial. Borek -- Chemical calculators at www.chembuddy.com BATE - pH calculator
  13. You must find out how to convert molarity to molality. Correct conversion formula will contain density and molar mass - you have to solve for density. Check out these concentration lectures for hints on converting (read about %ww to molarity conversions for general outline). Strange thing is that 1.0000M solution of KCl is 1.0312 molal. Looks like the data in question are questionable. Borek -- Chemical calculators at www.chembuddy.com concentration conversion calculator
  14. Borek


    Start with learning about Henderson-Hasselbalch equation. Then check buffer pH question 1 and buffer pH question 2 - although they don't address specifically your problem, they show how to deal with buffer preparation. Acetic buffer case is not different.
  15. Borek


    Stomach? Strong acid solution behaves as buffer as well - pH doesn't change much when you add small amounts of acids/bases. See buffer and buffer capacity discussion.
  16. Calcium carbonate minus carbon dioxide is either calcium oxide or lime water - where do you take them from? Borek -- Stoichiometry calculator www.pH-meter.info/pH-electrode
  17. And not MICROstere? 0.01*0.01*0.01 = 10-6 Perhaps you meant a cubic milimeter? Borek -- Stoichiometry calculator www.pH-meter.info/pH-electrode
  18. Borek

    redox reaction

    Do I read you correctly - KMnO4 solution is colorless? Borek -- General Chemistry Software www.pH-meter.info/pH-electrode
  19. IMHO what he is looking for is a way of preparing Sterno type gelled fuel: http://zenstoves.net/Sterno.htm Borek -- General Chemistry Software www.pH-meter.info/pH-electrode
  20. Na2SO3 Borek -- General Chemistry Software www.pH-meter.info/pH-electrode
  21. I would rather go with iodate solution prepared from solid directly in the volumetric flask, filling up to the mark. Then I would transfer exactly known volume of iodate to baker and I would add iodide and acid there, avoiding all steps that can introduce error to the iodine amount When titrating iodine you usually start with yellowish solution - and you don't add starch till solution loses almost all color. Borek -- General Chemistry Software www.pH-meter.info
  22. S4O62- + I- Borek -- General Chemistry Software www.pH-meter.info
  23. In all analytical methods I am aware off you prepare reagents in the same beaker/flask it will be used, to avoid reagent losses in transfer. You are right about side reactions, but if there are side reactions possible it is better to look for other method. Borek -- General Chemistry Software www.pH-meter.info
  24. Add starch just before titration end, when the iodine color fades. Otherwise it may react with starch in an irreversible way. Borek -- General Chemistry Software www.pH-meter.info
  25. If there is a lot of iodine it forms a stable compound with starch. When there are small amounts of iodine, reaction is reversible. Borek -- General Chemistry Software www.pH-meter.info
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