enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    At 10 000 ppm the solution is a deep red colour. As the concentration decreases the colour becomes orange, then a vibrant yellow, with the final 1 ppm sample a very pale yellow. In science and engineering , the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities , e.g. mole fraction or ...

  3. Internal standard - Wikipedia

    en.wikipedia.org/wiki/Internal_standard

    In NMR spectroscopy, e.g. of the nuclei 1 H, 13 C and 29 Si, frequencies depend on the magnetic field, which is not the same across all experiments. Therefore, frequencies are reported as relative differences to tetramethylsilane (TMS), an internal standard that George Tiers proposed in 1958 and that the International Union of Pure and Applied Chemistry has since endorsed.

  4. Golden rain demonstration - Wikipedia

    en.wikipedia.org/wiki/Golden_rain_demonstration

    Golden rain demonstration is made by combining two colorless solutions, potassium iodide solution and Lead(II) nitrate solution at room temperature to form yellow precipitate. During the chemical reaction, golden particles gently drop from the top of Erlenmeyer flask to the bottom, similar to watching the rain through a window.

  5. Hoagland solution - Wikipedia

    en.wikipedia.org/wiki/Hoagland_solution

    The main difference between solution (1) and solution (2) is the different use of nitrate-nitrogen and ammonium-nitrogen based stock solutions to prepare the respective Hoagland solution of interest. Accordingly, the original 1933 and the modified concentrations of 1938 and 1950 for each essential element and sodium are shown below, the ...

  6. Total dissolved solids - Wikipedia

    en.wikipedia.org/wiki/Total_dissolved_solids

    Bottled mineral water usually contains higher TDS levels than tap water.. Total dissolved solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular (colloidal sol) suspended form.

  7. Dilution (equation) - Wikipedia

    en.wikipedia.org/wiki/Dilution_(equation)

    Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution. To dilute a solution means to add more solvent without the addition of more solute. The resulting solution is thoroughly mixed so as to ensure that all parts of the solution are ...

  8. Winkler titration - Wikipedia

    en.wikipedia.org/wiki/Winkler_titration

    The second part of the Winkler test reduces (acidifies) the solution. The precipitate will dissolve back into solution as the H + reacts with the O 2− and OH − to form water. MnO(OH) 2 (s) + 4 H + (aq) → Mn 4+ (aq) + 3 H 2 O(l) The acid facilitates the conversion by the brown, Manganese-containing precipitate of the Iodide ion into ...

  9. Standard temperature and pressure - Wikipedia

    en.wikipedia.org/wiki/Standard_temperature_and...

    However, a common temperature and pressure in use by NIST for thermodynamic experiments is 298.15 K (25 °C, 77 °F) and 1 bar (14.5038 psi, 100 kPa). [4] [5] NIST also uses 15 °C (288.15 K, 59 °F) for the temperature compensation of refined petroleum products, despite noting that these two values are not exactly consistent with each other.