why are unused reagents should not be returned to the original container?
955039
Reagents, since they usually come into contact with other atoms, are easily contaminated. Even by the air, which contains many sub particles and substances that are harmful when interacted with. If they are returned to their original container. Aren't the other atoms of the substance getting contaminated as well? Hence here, there seems to be the problem of contamination and wastage. Hope that helps dear!!!
450796
companies describe expiry dates on medicines including antibiotics. What they mean is that one or more chemicals or rather we say ingredients lose their effectiveness. So when you return the medicines to the store they give it back to the company where they add the chemicals which lose their effectiveness and then again sell those.\n\nSo it is better to return the medicines back to the store rather than flushing or throwing in garbage which is harmful for the soil.
849268
I think you are in my class. -0-... do you have chem test tommorow?\n\nI believe it is d.\n\nEquilibrium has to be in a closed system.\nTemperature changes K value so it is necessary to keep in a constant temperature.\nEquilibrium basically is defined as equal forward and reverse reaction reates.\n\nConcentration does not necessary has to be same.
761616
One that will ideally:\n1) dissolve the component that you wish to collect but not the others. Then you can do a filtration, collect the filtrate and evaporate off the solvent to get back the component that you want.\nOR\n2) dissolve all those that you don't wish to collect but not the component that you want. Then you can do a filtration and collect the component that you want as the residue.\n\nHope this helps :)
104161
You could rig a "Dean-Stark Trap" on the side of your condensor. That will eliminate water from your esterification (assuming its similar to the Fisher esterification) and force the production of more water and product, until one of the reagents is used up or an equilibrium is achieved.\n\nAnother method would be TLC, comparing the starting reaction mixture to the final product.\n\nSpectroscopy (NMR, IR) could be used.\n\nFinally, you could just put some of your sample into a GC-MS.
212346
Opposite of dispose would be keep.\n\nOpposite of disposable would be permanant.
572840
No.  They have all been used.
848661
You have to consider two things here - \n\n1. Do you need to reference a field from the earlier form? If yes, you should not unload it until you have obtained all the values off of that form.\n\n2. Would you need that form again shortly? If yes, its better to set visible=false rather than unloading - because loading an unloading a  form causes an overhead, so if you're gonna need that form again and often, its better to keep it in memory by just hiding it.
901470
They're not available commercially. You have to purify them in a lab.
1187913
Because chemicals react with eachother, it is bad practice to place chemicals directly on the balance pans.  Residual chemicals from a previous experiment could be resident on the pan, resulting in contamination of your chemical, or worse, an unwanted chemical reaction.  This is why the majority of experiments require glass containers for chemicals.  Most chemicals to not adhere to glass like they might do to metal, and glass can be more easily identified as clean.
731517
Use the limiting reactant.
915628
They arent being "stored", they're being disposed of.
951540
No it is irreversible. Once the Nitrogen hydrocarbon link of aminoacids is destroyed, it could not be reformed.
684681
C because the solution is SATURATED with solute, meaning no more solute can be dissolved by the solvent in the solution.
421615
It depends on which method you are talking about and the end use of the water.  For drinking water they are strictly monitored.  For industrial reuse, you try to balance cost and quality so you can have problems.
375502
not for an extended period of time. Poop has had all of the nutrients already filtered out and used by the body, it is just the waste product left over and has minimal nutritional value. It could possibly be recycled once or twice for the left over kernels that did not get digested the first time through.
1157628
It depends on the activation energy and the relative energy states of the products.\n\nIn the gas phase, the sodium chloride and water formed are at such  a more stable configuration (as evidenced by the fact that this reaction is highly exothermic), that it is effectively irreversible.\n\nIn solution, however, you will find sodium ions, chloride ions, and -- due to the natural behavior of water -- a small amount of hydronium ions and hydroxide ions.\n\nSo, in solution, the reaction becomes a tiny bit more reversible, but not nearly enough to regenerate significant amounts of your starting products.  The equilibrium is heavily weighted towards the products (sodium ions, chloride ions, and water) because of the energetics of the reaction.