Ferdinand

For Beau,

"My problem is with the

>reaction of ammonia solution and silver as both as ion or solid. In

>particular I would like to know whether AgOH is possible from the

>reaction of limited ammonia solution (being a base) and either

>silver ion or solid. I have searched on the internet for AgOH with

>no result therefore I thought that when silver is reacted with any

>base it either forms a Ag20 precipitate or a Ag(OH)2- ion. I'm also

>not sure which one would be the product from limited ammonia. I

>understand that in excess ammonia silver will form a complex ammonia

>ion but dont know the limited solution. If the product is Ag2O can

>you include the reaction because I'm not sure if 2Ag + OH- --> 2Ag2O

>+ H+ seems quite right. Please can you help me with my query.

>Althought this is not likely to be in the exams it is still

>annoying me."

Colleagues, I seek an elegant answer here.

Thanks

Ferdinand

I cannot logically get my head around the dilation of time, or that time elapses differently according to who is observing what. But in particular, how was Einstein, or anyone else, able to reason that time was not an absolute and now have it confirmed by experimentation?

I am still not enlightened about why - though I can regurgitate some of the explanations that I do not truly understand.

I apologise if this has been raised, discussed and answered previously. If so, could you please direct me to an enlightening repsonse to my ignorance?

Thanks.

Ferdinand

Thanks for your reply. Interestingly, our GAA is very old - >15 years but there's no solid block ..it's all liquid...

Have you burned propanoic acid? If so...what's the "interesting" smell?

Nando

A colleague of mine ignited propanoic acid. The resulting smell was described as quite unsettling for him and some of his students. He then attempted to ignite glacial acetic acid which does have a flammable symbol on the reagent bottle. However, he could not ignite it. Can anyone enlighten(no pun here) us high school chemistry teachers why we weren't able to ignite flammable glacial acetic acid?

Thanks

Ferdinand

Woelen,

an interesting response from Ann....March 1, 2006

An aqueous solution of copper(II) sulphate will contain the hexaaqua ion and the pentaaquamonohydroxyl ion, one of which is violet and one green (Having been retired many years, I've forgotten which is which, but the answer was contained in Dr. Alan Sharpe's Inorganic Chemistry, published many years ago. It may be included in one of his later textbooks.) Is it possible that the violet ion changes to the green ion under the conditions discussed? The commonly encountered blue solution contains a mixture of the two ions.

Ann Burton

- Macclesfield, Cheshire, UK

Spirit levels have fluroscein(mispelt i think), I believe.

The mantles used in gas lamps are also radioactive. Thorium Oxide coatings?

My "Genie in a bottle" is always a winner, except it takes 1-3 seconds to run, and about 1 minute to prepare. So, I "ham" it up a bit.

Some people know about "I dream of Jeannie" and I've always been besotted by Barbara Eden. I have always wondered how they do the SFX of the genie coming out of the bottle. I've stumbled on a possible way that I use to introduce fast redox reactions of the non-explosive constricted kind.

So, that big puff of "smoke"(actually condensing water vapour) from the "genie's bottle" is spectacular. But you do it twice without your audience being aware that you have two bottles. We use conical flasks; one is a 100 mL one and the other(hidden one tha the students are not aware of) is a 5 L one. Pour about 10 mL of 35% hydrogen peroxide, while you're introducing the genie factor, or you can make it a straight chem lesson. While everyone is focussed on the conical(with safety glasses) sprinkle a small amount of potassium permanganate crystals( 3-5 grains quickly) and stand back. Genie comes out of the bottle. Careful, highly exothermic and if you put in to much grain you'll stain your surfaces as the genie comes out.

Now, once your audience has recovered, bring out from underneath your bench the 5 L conical flask. (Big Genie!!!) Pour perhaps 50 -100mL of 35% H2O2 and carefully but quickly drop in perhaps a pea-sized amount of potassium permanganate crystals -but no more...and watch - but don't blink because you may miss it!!! Don't panic about the cloud the shoots out of the top of the conical flask - it's just a concentrated amount of condensing water vapour that I keep hoing will turn into Barbara Eden.

A physics Or physical chemistry demo I love to do once a year is to get the atmosphere to crush a 44 gallon drum(or two) in about <0.25 seconds...The shock wave is something to behold! Watching skeptical kids' jaws drop to the ground as it happens is priceless.(Preparation time is excessive!)

I have always had the desire to throw a piece of caesium into water and simultaneously drop some into fluorine gas.

Tom is a very large fellow, who is also a fishmonger. What does he weigh?

The grinding of sugar in a darkroom....with mortar and pestle???

So, "Acids are ionic!!!!!"

Thanks, The Thing.

Aristotle "informed me" that there are four elements. Bruce Willis convinced me that there are actually five.

The green colour could be the result of the initial oxidation of iron atoms into iron II ions(green in solution) as copper II ions reduce to copper atoms. Some of the iron II ions will further easily oxidise to iron III ions(yellow to brown in solution - I like to call it "diarrhoea" coloured) as more copper II ions reduce to atomic copper. The NaCl simply dissociates and provides ions in solution to facilitate the charge flow and assists the previously mentioned redox processes to occur more efficiently. However, this is only one view of a possible mechanism. You may also want to read the thread "Nails in Copper II chloride...it is very enjoyable, in my humble opinion.

I have found this dialogue most enlightening...another reson why I'm so glad I've found this forum.

Interestingly, copper II sulfate solutions are slightly acidic, of course. Copper II nitrate solutions should also be slightly acidic due to aquated copper ions undergoing some hydrolysis - as in sulphate solutions. So, I am still totally ignorant of the lack of displacement, but jumping with excitement at Woelen's and YT's inputs. Thank you for taking this one up. Your investigative dialogues are so full of integrity that I seek to use the transcripts in my chem classes when we cover redox & metal displacement - with your permissions??

Okay over the years(about 15-20) I have quickly set up the metal displacement demo of a large shiny iron nail in royal blue copper sulfate solution.If not, I've gotten my students to do it. Each time as expected, the predicted observations are made - salmon pink solid produced, blue colour fades. Sometimes, I have unwittingly used copper nitrate solution instead or copper sulfate solution - thinking that all I really required was a ource of copper II ions in solution. But every time I've dipped that shiny iron nail into the copper II nitrate solution (and left it there) the iron nail remained shiny. No redox process. It has gotten to the stage where I make sure that it is NOT a copper nitrate solution to get my salmon pink solid.

Interestingly, I carry out a demo of iron nail in copper II sulphate solution regularly, or get my students to do it themselves. As expected, bright "salmon-pink" solid appears on the nail as the redox process occurs.

However, why does the redox process between iron nail's atoms and copper II ions in copper II nitrate solution NOT occur? That is, the iron nail remains shiny. Please excuse my ignorance, but no-one has been able to explain this anomaly to me.

When there is a reasonably stocked Chem store in your educational institution and you deal with Reaction Rates and Activation energy in your high school curriculum, KClO3 is in reasonable supply.

I also use a potassium chlorate and sucrose mix on top of my thermite. One drop of conc sulfuric acid starts the chlorate/sucrose(immediately) and easily sets the thermite off.

I am a high school science teacher and I have a repertoire of interesting and spectacular demonstrations that I incorporate into my lessons. Colleagues, I want to start a thread that titles some of the more memorable demoes you have encountered or conducted and could be demonstrated to Year 11s and Year 12s who are focussed on chemistryor physics

Some of the ones I'm listing below are now not permitted in high schools in Western Australia.

1. Plasma torch(my all time favourite - however CS2 is "banned" now)

2. Platinum Candle

3. Instant implosion of sealed 44 gallon drumwith boiling water in it

4. touchpowder

5. Acetylene/Oxygen balloon bomb

6. white phosphorus activities

7. melting phosphorus in boiling water in a darkened room

8. Coloured precipitations

9. Equilibrium Clock

10 rocket launching

11. levitation of superconductor

12. Dry ice experiments

13. Liquid nitrogen experiments

I hope some of these titles inspire some of you...could you keep the thread going or tell me of a thread that already exists on this?

Thanks

thank you jdurg...my repertoire is increasing thanks to this forum.

Ilja, one of my students once left the top off a reagent bottle with butyric acid in it. We got complaints from classes next to us and above us.

In the meantime, fold a piece of paper in half(don't make a crease otherwise space-time will not restore itself), poke a hole through it with a pen, and then unfold it....I think the navigators in Dune would be impressed.

woelen, by HN3, you DO mean ammonia(NH3) right?...or is there something else that has the formula HN3??

Time taken to travel, at light speed, up a stack of one mole of $2 coins (Aus) to the top = 159,000+/- 20% years