jdurg

That is correct. The simple procedure is as follows: 1): Have a known volume of water and determine the mass of the water either via weight, or from the density and the volume data. 2): Weigh a known quantity of ammonium chloride. 3): Have a good thermometer or thermocouple to measure the starting temperature of the water. 4): Make sure everything is done in a thermally isolated container. (I.E. use a styrofoam cup of Dewar flask to make sure there is no energy loss/gain from the surroundings). 5): Dissolve the known mass of the ammonium chloride in the thermally isolated water. 6): Measure the resulting temperature when it reaches a steady point. 7): Using the change in temperature, the mass of water and the specific heat of water, calculate how many joules were exchanged in the dissolution. 8): Divide this amount by the number of moles of ammonium chloride you used. 9): If the change in temperature was a positive change (I.E. the water was warmer after dissolution), then the sign on your answer will be negative. If the water was cooler after dissolution, then the sign on your answer will be positive. That's it.

Then I would without a doubt say that it was KI. Did your teacher do the preparation of all this? If so, it's possible that he/she has done this before so they have a premade solution of ammonia/KI. Otherwise, he/she put the KI into there without your class noticing.

MSDS sheets can be a bit misleading. If you read the one on water, it makes it seem as if water is an incredibly deadly chemical that will kill us all. So take that information with a grain of salt. If you are collecting elements it's a bad idea to do so without doing your research first. An element collection is a great thing to have, but it can be just as dangerous as a loaded gun if you are not careful. Most people wouldn't go hunting without some proper training first, and you really shouldn't go out collecting elements without doing some research first. A LOT of the elements will quite readily kill you in their pure form. Arsenic, thallium, lead, tellurium, antimony, bromine, chlorine, mercury, cadmium, barium, beryllium, rubidium, cesium, potassium, sodium, lithium, strontium etc. are all very nasty things and deserve a lot of respect due to their reactivity and/or propensity to end your life. I don't mean to scare you here, but I just want to make sure you are aware of what you are getting into. I believe that in either this thread, a sticky in this forum, or over at http://www.chemicalforums.com they have an entire section devoted to the safe collecting of the elements. It's vital that you read that so you can make sure you know what you're getting into. If you do have any questions that aren't readily answered here, feel free to PM me as I've been collecting elements for a few years now and have a substantial collection and have done a ton of research on the safe handling of these samples.

Potassium iodide. It is added to the ammonia/iodine mixture to allow the iodine to dissolve in water and form the I3(-1) ion MUCH more readily than without the potassium iodide.

I haven't looked at the link, but I'm guessing that they mention methylene blue as an additive? With excess water consumption, the biggest problem you will find is that you cramp up a lot more. The excess of water depletes the potassium ions from your system which leads to more muscle cramping than if you normal infusing your system with water. The hypokalemia is more of a problem than hyponatremia. (Especially if the muscle that's cramping up is your heart). People always seem to think that the more water you drink the better off you are, but I'd say a good analogy to this would be red wine. A glass of red wine every day will provide a lot of medical benefits, but a bottle of red wine each day will cause a great deal of harm to your body. The color of urine pretty much just indicates what your body is getting rid of. As I'm sure many have noticed, urine color is darker in the morning as your urine is collecting all of the 'junk' your body is getting rid of over night. During the day, your urine color tends to be a bit lighter than when you first void upon awakening. (Probably this is also because during the day you urinate more often than you do during the night, so the 'junk' can't accumulate in your bladder). For me, urine color is a great way to tell how much I've had to ingest in terms of alcohol. When I go out drinking, I always know when it's time to ease up on the booze when I take a leak and it comes out clear as water. As soon as all the color is gone, it means that I'm at my desired level of intoxication and that it's time to start drinking water instead of booze. As a result, I haven't had a "hangover" in years and always seem to maintain that perfect level of intoxication.

Heh. Yeah, after a few hours at the local pub it will come back to you, but you won't be able to do anything about it.

CsOH is actually the strongest base that mankind knows about at this moment. It's just very expensive so any of these 'strongest base' uses are better taken care of with cheaper, 'less strong' bases.

HF is a paradoxically weak acid. I say that because it is scientifically 'weak', but it's INCREDIBLY toxic and dangerous to work with. For the hydrohalic acids, acid strength increases as you move down the group. So HI is stronger than HBr which is stronger than HCl which is stronger than HF. HF is weak because the fluorine atom does NOT want to dissociate and form H+ and F-. The hydrogen-fluorine bond is fairly strong, so very little of the acid dissociates when dissolved in water. The exact reason why it attacks glass I'm not really sure about. It's most definitely not because of the F- ion for multiple reasons. Number one is that HF is a very weak acid and there isn't a heckuva lot of F- ions in a solution of HF. Number two is that the F- ion does not attack glass. A solution of sodium fluoride, no matter how concentrated, can safely be stored in glass containers.

KOH and CO2 will only give potassium bicarbonate. That hydrogen atom won't just dissapear.

It would make sense, because the decomposition of hydrogen peroxide is a multi-step process through which various intermediates are created. If memory serves me right, O- is one of those intermediates as H2O2 decomposes into H2O and O-. Then another molecule decomposes and forms another H2O and another O- which forms O2. If you are bubbling SO2 through there, the O- will oxidize the SO2 into SO3 which will then go on to form H2SO4.

Solid ammonium hydroxide does not exist. Never has and never will.

Hydrogen peroxide is most certainly not an ionic compound. Whomever told you that it was is incorrect. The reason it's not called dihydrogen peroxide is because there is absolutely no need to do that since the only way to combine the hydrogen and a peroxide is in the form of H2O2. It's called 'peroxide' because the term 'per' means 'more than one' and this particular "oxide" is composed of more than one oxygen atom. Dioxide would mean 'two oxides' due to the 'di' prefix.

Chances are that if you were to burn copper with sulfur you'd be more likely to wind up with copper sulfide (CuS) than you would copper sulfate (CuSO4).

Nope. While there may be a reaction at first, the formation of a protective barrier of the hydroxide/oxide on the surface of the aluminum will immediately cease any and all reaction. You would have to have a way to contantly remove the coating from the metal in order for it to keep reacting. With stuff like sodium and potassium, any hydroxide that is formed is very water soluble so it will immediately move away from the metal's surface and allow more metal to react. Aluminum oxides and hydroxides bind VERY tightly to the surface of the metal.

That's because perfectly clean aluminum has a solid layer of aluminum oxide on it. Aluminum metal is INCREDIBLY reactive. In fact, it's right up there with sodium and potassium in terms of reactivity. Pure aluminum without any oxide coating on it will rip water apart quite rapidly. The thing is, aluminum readily reacts with oxygen and forms a layer of oxide which adheres strongly to the metal and does not want to come off. As a result, it becomes fairly non-reactive as we see it. It's just that we're not seeing "real" aluminum. The reason why mercury is able to make aluminum react like crazy is that Hg removes the oxide coating from the Al allowing the highly reactive metal to react with anything and anything around it. Sodium hydroxide attacks aluminum because it removes the oxide coating and allows the raw metal to react with the water. Acids also do the same thing by slowly removing the oxide layer and then allowing the metal to start reacting with both the acid and the water.

Is that % by mass? Because if it's 12% by mass, it means that for every 100 grams of solution you have 12 grams of sodium hypochlorite. With that information, you should be able to easily figure out the molarity you need.

Another way to look at it is in terms of oxidation numbers. In water, oxygen has an oxidation number of -2 so it gets the name 'oxide'. The technical name for water is dihydrogen monoxide, but in reality 'hydrogen oxide' would work just fine since oxide denotes oxygen in a -2 state and in order to balance it out you would need two hydrogen atoms.. In hydrogen peroxide, the oxygen atoms have an oxidation number of -1, therefore it gets the designation 'peroxide'. In order to balance out the charge, you need two hydrogen atoms so you get the formula H2O2 and the name hydrogen peroxide.

Algebra is a DEFINITE subject that you need to master in order to be successful in chemistry, and some fairly simple calculus isn't required, but will be immensely helpful in certain areas.

I had always believed that it was in reference to atmospheric gases. Otherwise, every gas would have a vapor density greater than 1.

I think the big separation between primary and secondary explosives is what is required to make them 'explode'. A primary explosive will explode whether it is confined or in the open air. A secondary explosive will only explode if it is confined while it will burn rapidly if left in the open air. I think nitrocellulose is considered a secondary explosive since it will burn rapidly in open air, but if you confine it in a tight space it will explode. (Although, I get this feeling that I'm confusing this with some other type of classification).

I'd say that the best way to do this calculation is based on weight. So 10,000 ppm hypochlorite in terms of weight would mean that per million grams of solution, 10,000 would be hypochlorite. Since your solvent is water, finding the density and relating that to molarity would be the easiest thing. One mole of NaOCl weighs 74.45 grams. 51.45 grams of that is the OCl- ion. So if you do the 10,000 grams of OCl- per million grams of solution, you would first need to calculate how many moles of OCl- you need to get 10,000 grams of the ion. So 10,000 divided by 51.45 = 194.3635 moles of the ion. Since you can't just add the OCl- ion, you need to now figure out how much mass 194.3635 moles of NaOCl weighs. That calculation turns out to be ~14,470.3596 grams. So you take this weight and subtract if from the 1,000,000 grams of total solution which leaves you with 985529.6404 grams of water. With a density of 1g/mL, you get a volume of 985.5296 liters of water. So you now see that your final solution will have 194.3635 moles of NaOCl per 985.5296 liters of water. That's a molarity of 0.19722 Molar. It should now be no problem to calculate how much NaOCl solution you need to use to get a final concentration of 0.19722 M which equals 10,000 ppm NaOCl by weight.

H2S smells like rotting eggs and the side effects of inhalation are a numbness of your scent receptors followed by death. It's a poisonous gas just as hydrogen cyanide is. Thankfully, the human nose can detect hydrogen sulfide faaaaaaaaaaaaaaaaaar before it gets to toxic/lethal levels. The only problem is that it does numb your ability to smell so after a short while you can't smell it any more. (As a kind of gross side note, a bit of hydrogen sulfide is sometimes contained in human flatulence. As a result, when you pass gas you can usually smell it quite strongly right away, but after a while you can't notice it anymore. If a different person comes into the area, however, they'll probably smell it quite a bit. This just shows how sensitive our noses are to H2S since it's a pretty toxic gas but we can sense it before it even comes close to being bad).

MnO2 will work as well, in fact, that's what was used to isolate chlorine gas the first time it was purified. However, it is faaaaaaaaaaaaaaaaaaaaaaaaaar less efficient than KMnO4 or Ca(OCl)2 is. Also, the calcium hypochlorite is a bit easier and cheaper to come by.

Yes, but generally only as an ion such as Hg2(2+).