Is it advisable to prepare equilibrium mixture starting from both directions?
928969
I can't see any reason for not advising that, provided you didn't mix up the equilibrium constants and the values for each reactant and product.
725280
http://www.mixturesweb.com
332721
Equilibrium considerations\n\nThe catalyst has no effect whatsoever on the position of the equilibrium. Adding a catalyst doesn't produce any greater percentage of ammonia in the equilibrium mixture. Its only function is to speed up the reaction.\n\nRate considerations\n\nIn the absence of a catalyst the reaction is so slow that virtually no reaction happens in any sensible time. The catalyst ensures that the reaction is fast enough for a dynamic equilibrium to be set up within the very short time that the gases are actually in the reactor.\n\nFinely divided iron and Molybdenum can be used as catalysts.
521266
This sounds like homework, so I'll give you the ideas but not the data.\n\nThe enthalpy of the mixture at standard conditions is the sum of standard heats of formation of the components of the mix. It will be given in kJ/mol (Ar is 0 kJ/mol being an element, the other two you can look up in tables or on internet). \n\nThen you need to adjust for the sensible energy difference compared to standard conditions : you will also need to look up the specific heat of each component (usually expressed in kJ / mol ºK) and multiply the specific heat of each component by the amount and by the difference in temperature. Make sure you have everything in the same units.\n\nRemember if you are working in moles its easier because to a first approximation, one mole of any gas occupies the same volume (if you undrestand how to allow for deviations from the ideal gas laws, you wouldn't be asking this question) and I assume that the percentages are volume percent, not by weight\n\nEnjoy
883855
The samples must be homogenously ground to enable the solvent to fully soak into the sample and extract the compound you want in question. Also there is a question of statical averages so a uniformed powder sample is the best for this process. If the sample is lumply or too big the solvent can't fully soak into it and wherefor not all of your compound in question is extracted by the process (Then the solvent fills up the soxhlet thumbie (sp)). If this happens you will get a incorrect value then you come to do the maths in determinating the amoult of the coumpound in question.
617970
I am terribly afraid of the equilibrium problem.. the first one on the free response!!! well, good luck!
842422
Yes, it is true that the density of a solution is different of solvant but tjis difference is small ; So , i propose to dissove 40g of amyl acetate in a liter of water if that acetate is a solid. If that acetate is aliquid the total volume will be 1.04 l and you must use 47 cc tp water
607425
Yes, provided the conditions are right. For example if the reaction\n\nA + B -> c + d\n\nis exothermic, the reaction in reverse will be endothermic, i.e. you will have to supply the heat.
143220
Yes, only if the volume difference is enough to compensate for the difference in temperature.\n\nOtherwise, no.  It is not logically or physically possible, given the same amount and the same environment.
792038
For the forward reaction (from left to right), there is a decrease in enthalpy, which indicates it will tend to proceed as written, to products.\nThe entropy increases from left to right (products are gaseous), and this also favours the forward reaction to proceed to products.
462489
put one of the acids in the titer, the other in the flask underneath.  Use a magnetic stirrer in the flask to ensure good mixing and ensure that you take required precautions (like goggles gloves lab coat ...possibly in a fume cupboard).\n\nThe two acids don't react with each other but is this 4:1 mix not acqua regia?
1067508
depends if the mixture is bonded by a physical or chem bond....there is magnetic separation,distillation,fractional distillation,evaporation,crystallization...etc...why dont u look up a chemistry book
696442
It would depend on what the nature is of the unwanted impurities. One could use chemical separation or distillation.  Distillation would be the easiest.
550924
I believe that at equilbrium, you would have a gradient of concentration throughout the liquid from top to bottom.  At the top, you would have primarily A and B reacting.  At the bottom, you would have primariliy AB dissassociating.  In between, you would have various degrees of A, B and AB as A and B rise up from below and AB falls from above.  The magnitude of the gradient would depend on the reaction rate.
310782
one of your solvents is more polar than the other (in this case acetone) the substances to be separated by chromatography will move the most in a solvent mixture they are most similar to. Remember like dissolves like. So if your unknown is easily dissolved in a non-polar solvent like hexanes then a non polar solvent will move it the most on the paper. If your substance is very polar, IE. an organic acid. It will stay near the bottom of your chromatography paper, when using a non-polar solvent mixture. 9:1 ether:acetone is actually quite non-polar, you can progressively increase your solvent polarity by making multiple solvent mixtures with changing ratios 8:1, 5:1 etc.   Obviously, you must use a new piece of chromatography paper each time you run a new experiment (unless your spots didn't move at all!). The basic concept of these experiments is polarity and how it relates to separating a mixture. Remember, like dissolves like!
1079987
No safe way to do it.  Distillation perhaps, but that's not safe as sulphate fumes are not that good for you.  \n\nGrab the stock bottle and make up a fresh solution.
149472
Hey I'm studying physical and chemical equilibrium too, currently.The answer is that it will definitely have units when the concentrations have different powers.Just try and work it out with the units and it will be very clear.