Why when diluting Acid do you add the acid to the water rather than the water to the acid
217150
Acid dilutions usually produce heat, and potential spattering.  If, for instance, you had to dilute a strong acid by a factor of 2 (let's say you're taking 12 M HCl and diluting it to 6 M), and the material begins to boil over after you'd added 10% (so you're taking 100 ml of acid and 100 ml of water).  If you're adding water to acid, you've got a resultant solution that is now approximately 11 M, which can cause some serious damage to skin.  If you're adding acid to water, your resultant solution is only 1.1 M, which, while still dangerous, is much easier to control.\n\nYou have less chance of having a violent reaction when you add acid to water than the other way around.
526487
Without knowing exactly what you did I can't answer this question!  Dissolution in dilute sodium hydroxide solution, filtration to remove any fillers etc, re-precipitation with hydrochloric acid and isolation by filtration should have given you an answer of some sort. Not exactly accurate though.
550727
You don't really say, but I'm assuming that you had a standardized solution of something like NaOH that you used in the buret, and you used that solution to determine the concentration of an acid by titration.  You also measured volumes of the acid for titration using a pipet.\n\nOK...So, for a).  If a bubble is present in the buret at the beginning of the experiment and it stays there the entire time, you shouldn't have any effect on your answer.\n\nFor b), if the bubble is not there at the end, then your buret reading will be off.  The readings from your buret would indicate that you put more sodium hydroxide into the flask of acid than you actually did...Does that make sense?  So, the concentration of your acid will actually be lower than your calculation says it is.\n\nc) is more difficult for me to answer, since I'm not really sure whether you determined the end-point of yoru titration by going to a specific pH, or whether you looked at a graph of pH and volumes of base added to dettermine the equivalence point.  If you did the first way, then your calculated result will be lower than your actual result.  If you did it the second way, then it really should affect your result.\n\nd) water in the pipet will dilute the acid as you dispense it, so that you are actually putting less acid in each titration than you should.  So, your calculated answer will be lower than the actual concentration....\n\nHope this helps.
567547
I think you are leaving out the first step.\n\nRemember that 12.0 M means 12 moles of HCL per liter of aqueous solution.\n\nTo understand the equations so that you can use them correctly, first think that you will have to add some amount of water to some amount of the concentrated solution to make it the dilute solution.\n\nso, 12 mol/liter , assuming you had a liter of the solution, you keep the same number of moles and add water\n\nhow much water do you add to get to the weak, .6 mol/liter concentration\n\n12 mol/ (1+x) liters = .6 mol/liter\n\n12/(1+x)=.6\n12=.6(1+x)=.6+.6x\n11.4=.6x\n19 = x\n\nso if you had a liter of the solution at 12 M, you would have to add 19 liters of water and then you would have 20 liters of solution at the diluted .6 M\n\nbut you don't need that much of the final solution, so you use the same ratio of water addition, but only start with enough concentrated to end with 300 ml\n\nthe ratio is 19 to 1\n\nso 1/20 * 300 = 15   you need 15 ml of the conc. solution\n   19/20 * 300 = 285  you add 285 ml of water \n\nthe total is 300 ml of the .6 M solution\n\nnow look back at the equations and you will see where they came from and how to apply them properly
47904
Simple. To avoid salt deposition on the cathode and anode. Simple tap water has many salts, whereas distilled water has a very less or negligible amount of salt. Answer is according to my logic. Need'nt be correct.
436204
tiny amounts of chemical can stick to differnt things, like stir bar, stir rod, thermometer and if you remove these items before the experiment is over then you remove some chemicals.  Other kinetics events that your not considering. as in pressure, humididtym and so on.  If you used a Ph probe then maybe it wasn't calibrated right or isn't properly maintained
321686
NH4ClO4 --> NH4^+ + ClO4^-\n\nNow in a water solution,\nClO4^- + H2O --> HClO4 + OH- --> This doesn't happen because HClO4 is a strong acid.  Therefore the only contribution to the pH is from the NH4^+\n\nNH4^+ <=> NH3 + H^+\nYou start with [NH4^+] = 0.40 M, and [NH3]=[H^+] = 0 M; after undergoing equilibrium [NH4^+] = 0.40 - x, while [NH3]=[H^+] = x; Ka = [NH3][H^+]/[NH4^+] = (x)(x)/(0.40-x) = Kw/Kb = (1 x 10^-14)/(1.8 x 10^5)\nAssume x << 0.40, so x^2/0.40 = 5.56 x 10^-10\nx = 1.49 x 10^-5 M = [H^+]\npH = -log(1.40 x 10^-5) = 4.827
530925
Think about the relative concentration gradients of specific solutes. You clearly wouldn't infuse something that would cause water to move out of the vasculature into the brain, you would want something that would do the opposite.
458466
Firstly, I would like to indicate that the bonds that chlorine forms with hydrogen are not hydrogen bonds at all. Hydrogen bonds are only present in compounds of hydrogen with the three most electronegative elements, i.e, fluorine, oxygen and nitrogen. Hence, hydrogen bonds may be found in water and ammonia, but not in hydrochloric acid.\n\nAlso you need to remember that the hydrogen bonds are intermolecular forces or attraction, that is the attraction between the hydrogen of one molecule of - taking the example of water - to the oxygen of another molecule of water. The bond within the molecule H - O - H is predominantly covalent, as it is formed by the sharing of electrons. The molecule might have an ionic tendency, how much depends on the electronegativity difference between the two elements sharing the electron.\n\nHence the bonds between the hydrogen and chlorine atoms sharing the electrons are predominantly covalent, with a slightly ionic tendency. Henceforth, water is very much an important factor in ionising an acid, and increase the hydrogen ion concentration in an acid.\n\nI hope this would be of good help to you.
486218
The sourness of water is due to it's high acidity as acid taste sour. Therefore  lime is added to neutralize the acidity and thus the sourness. Also alum requires an alkaline medium to work and lime provides that.
156041
Not trying to get some help with a chemistry homework problem, are you?\n\n\nOkay, my guess is that the molecules of one of the liquids fit into the "gaps" between the molecules of the other.  Kinda like mixing a quart of pebbles with a quart of bigger rocks.  Since some of the pebbles with fit between the bigger rocks, the combined volume will be noticeably less than two quarts.
66860
At a higher temperature, the water molecules are further apart, thus creating more space for the molecules of sugar.  Consider two identical bottles: (A) is filled with sand and (B) is filled with gravel.  If you pour water in each bottle, which one will take more water?  Obviously (B) because there is more space available.
417200
Ok, this is a weird question, but here's my best answer.  The 2 liquids stay separate because of density.  The green liquid is cooler and contains salt, both of which increase its density.  The red liquid is warmer (its molecules are moving faster and are farther apart) so it's less dense and should float on the denser green solution (unless you shake them, which is why the card method is used).
220728
You have to prevent the hotsauce from staining the pH paper. Run hotsauce through the filter paper; the pH of the filtrate will be about the same as the whole hotsauce.
153567
Buffers resist change in pH. This is generally a result of the buffer containing a mix of a weak acid and the salt of the conjugate base. \n\nWhen you add NaOH to the buffer, it dissociates into Na+ and OH-. The OH- reacts with the H+ ions which the weak acid has dissociated into (along with the conjugate base) up to the acid dissociation constant, Ka, of the acid.\n\nThis shifts the equilibrium of the dissociation reaction of the acid, and more dissociates, maintaining a relatively stable pH, as compared to when the NaOH is added to the distilled water. (If you had instead added a base, it would instead have shifted the equilibrium of the base, and, instead, more of the base would have reacted with the free H+, again, keeping the pH relatively constant)
555211
I'm not 100% sure, but it seems like this procedure would neutralize any acids in the solution.  The Hydroxide would turn acid to water.  Any remaining hydroxide would combine with Calcium to form Calcium Hydroxide, which has a low solubility.  This would then precipitate out of the solution.  If the solution is mostly organic, it would also adsorb most of the water and remove it form the organic phase.
421576
Na2SO4 + H2O\n\nYou always get a type of salt plus water in acid-base neutralization.