What are the properties of a good precipitating agent?
82586
It has a cation or anion that isn't soluble. Stuff like NaCl won't work, because Na and Cl are always soluble. KBr has the same problem. But stuff like NaOH (the OH forms insoluble metal hydroxides) works well.\n\nBasically, you have to look at the solution and the precipitating agent and see if they'll form an insoluble compound.
990586
You cant.\nThe key word here being "completely".\n\nNo matter how insoluble a given precipitate is, it is always soluble to some, very minor, degree.\n\nHowever, by choosing to precipitate a compound with a very low, practically zero, solubility, the ion is (for all intensive purposes) removed from solution.\nWhen dealing with such low-low solubilities, the Ksp value for the compound becomes important...the lower the Ksp, the lower the solubility.
721477
Sodium sulfate is an important compound of sodium. When anhydrous, it is a white crystalline solid of formula Na2SO4. The decahydrate, Na2SO4•10H2O, is known as Glauber's salt. Sodium sulfate is mainly used for the manufacture of detergents and in the Kraft process of paper pulping, although it has many other uses. About half of the world's production is from the natural mineral form of the decahydrate (mirabilite), and half from by-products of chemical processes\n\nPhysical and chemical properties\nNa2SO4 is chemically very stable, being unreactive toward most oxidising or reducing agents at normal temperatures. At high temperatures, it can be reduced to sodium sulfide. It is a neutral salt, which forms aqueous solutions with pH of 7. The neutrality such solutions reflects the fact that Na2SO4 is derived, formally speaking, from a strong acid (sulfuric acid) and a strong base (sodium hydroxide). Sodium sulfate reacts with an equivalent amount of sulfuric acid to give an equilibrium concentration o the acid salt sodium hydrogen sulfate:\n\nNa2SO4(aq) + H2SO4(aq) → 2 NaHSO4(aq) \nIn fact the equilibrium is very complex and dependent on concentration and temperature, with other acid salts being present.\n\nNa2SO4 is a typical ionic sulfate, containing Na+ ions and SO42− ions. Aqueous solutions can produce precipitates when combined with salts of Ba2+ or Pb2+, which form insoluble sulfates:\n\nNa2SO4(aq) + BaCl2(aq) → 2 NaCl(aq) + BaSO4(s)\n\nSodium sulfate has unusual solubility characteristics in water, 3 as shown in the graph below. Its solubility rises more than tenfold between 0 °C to 32.4 °C, where it reaches a maximum of 49.7 g Na2SO4 per 100 g water. At this point the solubility curve changes slope, and the solubility becomes almost independent of temperature. In the presence of NaCl, the solubility of Na2SO4 is markedly diminished. Such changes provide the basis for the use of sodium sulfate in passive solar heating systems, as well is in the preparation and purification of sodium sulfate.
517995
67.  AgCl <---> Ag+ + Cl-  Ksp = [Ag+][Cl-] = 1.8 x 10^-10\n[Ag+] = 0.001/2 = 0.0005 M; [Cl-] = 0.0025 M; [Ag+][Cl-] = 1.25 x 10^-6, as this is greater than Ksp, a precipitate will form.\n\n68.  SrCrO4; Ksp = [Sr2+][CrO42-] = 3.5 x 10^-5; molar solubility = [Sr2+] = [CrO42-] = sqrt (3.5 x 10^-5) = 0.0059 M\n\n69.  Total volume = 3L  [Fe2+] = 0.150 * 1/3 = 0.050M; [OH-] = 0.0333 * 2 / 3 = 0.0222 M.  Ksp Fe(OH)2 = 4 x 10^-38.  (0.050) * (0.0222)^ 2 >>> 4 x 10^-38, so a precipitate will form.\n\n73.  Pb3(AsO4)2 <---> 3 Pb2+ + 2 AsO43-.  If solubility = x, then [Pb2+] = 3x, [AsO43-] = 2x.\n4.0 x 10^-36 = [3x]^3[2x]^2 = 108 x^5 ==> x = 3.26 x 10^-8
1087032
try Vogel's "Qualitative Inorganic Analysis", I'm pretty sure it has all the answers 4 u.\n\ndont care editions, but for 7th ed, ISBN is 0582218667\n\n****\nokey then, from Vogels\n\n1) when heated, lead nitrate decomposes to white solid lead oxide (PbO), brown gas (NO2) and oxygen gas. Brown gas decolorizes when contact with water. \n\n2) ammonia odur. ammonium compounds are all volatile towards heat and decomposes to ammonia and an acid but quickly recombine if the acid, in this case, hydrochloric acid, is a strong acid.\n\n3) anhydrate copper sulphate is white, hydrate copper sulphate is blue. I have no idea which one you actually heated. If it's anhydrate, no change; if hydrate, blue ---> white.\n\n4) blue precipitate forms initally, but resolve upon excess reagent, clear blue soln results due to the formation of copper complex [blue precipitate: Cu(OH)2*CuSO4, complex: [Cu(NH3)4]^2+]\n\n5) brown precipitates froms [Cu(OH)2], no change with excess reagents.\n\n6) metal-gray stipe (magnesium stipe) gains a redish brown color due to formation of copper metal. Possible decolorization of the soln (depends on how much magnesium u actually put in)\n\n7) volatile reaction, solid metal solves,ignitable gas is formed. (if phenolphthalein is added to water initally, soln becomes pink)
799604
If the ionic compound is soluble, no precipitate is formed.\n\nOn the other-hand, if an ionic compound is not very soluble in the solvent, then it will precipitate out of solution.\n\nFor example, Sodium chloride is soluble and Silver nitrate is soluble, but if these solutions are mixed, some of the Silver ions will react with chloride ions and form solid Silver chloride precipitate.
25944
It highly depends on what you're mixing.\n\nTypically, the good signs to look for are these:\nEvolution of Gas\nEvolution of Heat\nForming of Precipitate (two clear liquids become murky)\nChange of Color\n\nPretty much a change in any physical quality. If you want to figure out if a chemical reaction occurs without actually doing an expirement, look up "Reaction Spontenaity"
993350
easy!\n\nadd silver nitrate\n\nit will make silver bromide precipitate.\n\nthis is pale cream in colour.\n\nfurther confirmation is done by adding conc ammonia to it, and if it dissolves, it proves that the original solution had bromide ions.
770030
primary standards are materials that have the following properties(or at lest most of them)\n1-they should have high molecular weight\n2-they shouldn't be sensitive to environment (like atmospheric oxygen)\n3-they must have completely known formula (including crystallization water) \n4- they should be powerful reactants( have 100% yield)\n5- it's much better if they are cheep and not poisonous.\na good example of them is KHP (potassium Hydrogen phthalate) if you solve a known weight of a primary standard in water you will have a solution with known concentration which won't change over time.\nsecondary standards (like NaOH and HCl) in the other hand don't have some of those properties, and the concentration of their solutions might change over time and is not exact, so you must use a primary standard to measure their concentration. but they are used mostly because they are very cheep and easy to use, or are more powerful reactants.
640615
Well depending on your application for it, there can be different pros and cons. But generally PDC has alright impact properties, not the best out there by far. Has good hardness. You can find these properties on matweb: http://www.matweb.com/search/SpecificMaterial.asp?bassnum=PMO861\nas well at Basell's website:\nhttp://www.basell.com/portal/site/basell/index.jsp?epi-content=GENERIC&range2_from=&grade=1287&brochure_start_doc=0&epi_menuItemID=483732eb145b68bdf5305285a0f034a0&displayproperty03=&displayproperty02=&range3_from=&region=0&displayproperty01=&staticcontent_title_sort_order=&searchType=ProductGradeSearch&resin=0&pressrelease_start_doc=0&brochure_title_sort_order=&displaycategory03=id1&displaycategory02=id2&displaycategory01=id0&staticcontent_start_doc=0&range1_to=&viewID=single_product_grade&VCMChannelID=9039ea2b61a89f00vcm100000000c53f3cc3____&range2_to=&pressrelease_title_sort_order=&range3_to=&range1_from=&productgrade_start_doc=0&product_name=aa54563d2f437010VgnVCM100000646f3c14RCRD&beanID=936658885\nas for price, I'm not 100% sure, but I'd say a safe bet is less than $1/lb.
784863
The precipitate is a solid, and it usually is in the form of a salt (i.e. NaCl)  If you are given an equation that begins with two liquids, for example, and one of the end products is solid (s), then you know that that is a precipitate.  \n\nPrecipitation can occur for a few different reasons.  One reason can be due to the insolubily of one of the reactants and wil result in precipitation  This can also be due to supersaturation of the mixture that causes the insoluble material to precipitate out of solution.\n\nWikipedia has a nice example using Silver Chloride (AgCl).
820617
Here are some essential properties of a propellant:  It must deflagrate (burn very rapidly), but not detonate (instantly decompose).  It must produce a great volume of gas, compared to its uncombusted volume.  It must be stable enough to be handled safely prior to its ignition.
121699
Surface tension\n\nWater's utility as the universal solvent.
1035532
In the pharmaceutical industry, the precipitation of active pharmacuetical ingredients to their solid form is very key.  This is because the different solvents and or precipitation conditions can potentially form different polymorphic forms (they can pack in different repeatable patterns when precipitating) that can be redissolved differently and even have different melting points.  The importance of this is that each polymorphic form can be patented independently which essentially for lisencing purposes makes it a new drug free of patent restrictions since its redissolution properties are most likely different (which is related to drug delivery in vivo).\n\nThe overall purity of a product can be changed by altering the precipitation conditions.  The goal is to find a set of conditions that are most selective to the molecule of interest over undesirables.
1093905
http://en.wikipedia.org/wiki/Furfural\n\nClick on the link above to research about some of the chemical properties of furfural!
231862
How about Enzymatic Yield Optimization?  You might also use Enzymatic Precipitate Optimization if the result is a precipitate.
141058
sodium sulfte is soluble, but barium sulfate would form as a precipitate. Thus\n\nBaNO3 + Na2SO4 -> BaSO4 + 2 NaNO3, or simply\n\nBa(2+) + SO4(2-) -> BaSO4