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MrHomeScientist
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The other complication with bleach is that it's unstable, and you don't know how long it's been sitting on the shelf. This was a while ago so my
memory is bad but someone (either here, on YouTube, or at a local science fair that I judged) did an experiment titrating several 'fresh' bottles of
bleach and the concentrations were all over the place. Great idea for a project, with interesting and useful results.
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Herr Haber
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Quote: Originally posted by MrHomeScientist  | | The other complication with bleach is that it's unstable, and you don't know how long it's been sitting on the shelf. This was a while ago so my
memory is bad but someone (either here, on YouTube, or at a local science fair that I judged) did an experiment titrating several 'fresh' bottles of
bleach and the concentrations were all over the place. Great idea for a project, with interesting and useful results. |
I did see that here somewhere.
Concentrated bleach looses a lot of chlorine really fast when it's fresh and the best workaround I found was to bubble more chlorine.
Of course, I use TCCA and HCl and in a world with no bleach these will have disappeared long before bleach.
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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roXefeller
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| Quote: Originally posted by elementcollector1 |
Lead will also be replaced by less 'toxic' alternatives, in much the same manner as mercury. This is already happening in niche applications such as
weights for Cub Scout Pinewood derbies/other hobbies, where sintered tungsten, tin and (very rarely) bismuth have provided substitutes. Ironically,
this is one product of lead-phobia that will actually lead to an increased supply of elements to the collector or chemist, as tungsten will
technically become easier to source in this manner in reasonably pure ingot form. See also: the entire state of California, apparently.
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I was teaching a parent a couple years ago about how to weight one of those cars without having to spend 20-30 dollars on precast weights that were
nowhere to be found on the winning cars. Said I used lead sinkers and an old tuna can. Just the way it was when I was growing up. The new crop of
grey beards didn't like my advice, though we had the winning cars for multiple years. Molten metal casting, lead, arrrgh. Not sure how we ever won a
revolution. Speaking of which, lovely antique fort in Pennsylvania, Ft Roberdeau, that was a refining location of strategic importance to supply lead
for colonial America. Had to hold back indian and British raids to protect the lead stores.
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Pumukli
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No need to defend bleach makers! For decades, regular bleach was 5.25% (0.7 M or what) and it was no problem. It slowly lost its hypochlorite content
but the process was known and "could be live with".
What they do now is manufacture half-strength solution and sell on the same price as the regular one.
Or even more dilute solution, what they seem fit.
What I tested all was made within a few weeks of the titration.
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elementcollector1
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| Quote: Originally posted by roXefeller |
I was teaching a parent a couple years ago about how to weight one of those cars without having to spend 20-30 dollars on precast weights that were
nowhere to be found on the winning cars. Said I used lead sinkers and an old tuna can. Just the way it was when I was growing up. The new crop of
grey beards didn't like my advice, though we had the winning cars for multiple years. Molten metal casting, lead, arrrgh. Not sure how we ever won a
revolution. Speaking of which, lovely antique fort in Pennsylvania, Ft Roberdeau, that was a refining location of strategic importance to supply lead
for colonial America. Had to hold back indian and British raids to protect the lead stores. |
It was much the same during my time in the Boy Scouts. An old tent roof we used for cooking had a silvery splotch on it. I asked the Scoutmaster, and
he said it was from years past, when one of the older Scoutmasters used to cast lead into bullets. Having found some old bullets embedded within
stumps and others, I asked to melt lead in a similar fashion. He claimed that it was too unsafe. (Granted, if a splotch of molten lead made it ~10
feet up to that tarp, he had somewhat of a point. Still...)
During the same trip, a different parent who had been in Scouting for several years knew of my chemistry hobby, and gave me most of a road flare
containing strontium and sulfur (and wood chips). To amuse the other Scouts, he put the cap in the campfire, and we watched as it burned a brighter
red than anyone was prepared for. I explained that it was the strontium inside the flare that lent the color - a lesson the others would have
distinctly missed if the current Scoutmaster had had his way.
One thing I'd like to see taught in schools more is the difference between acute and chronic poisons. Maybe then we wouldn't have to deal with foolish
chemophobes who think touching lead metal is an instant, sure death.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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RogueRose
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I think a lot of the scarcity has to do with where people live. I've seen a decrease in bleach concentration where we used to be able to get "ultra"
which was 8% and standard was 6-6.25%. Now a lot of it is 3% (generic cheap stuff) and 5-5.25% for name brand. I have a feeling this has more to do
with reducing the cost in production so they can keep the same price point on the shelf. This is very similar to the size of ice cream containers
going from 1/2 gallon to 1.5 quarts but the price stays the same. Fruit juices are similar - instead of 2 quarts now it's 52oz, a 12oz reduction but
same price point.
I've found that 12.5% is always available as pool shock, especially from May to August ($4 in May, $2 in August clearance). It's usually available
year round at pool & hot tub supply stores, normally at the higher price of $4. Now it's also possible to buy it in 15, 20, 30 and 55 gallon
drums for $1.50-2.50 per gallon @ 12.5%
I guess I'm luckier than I know when it comes to H2O2 b/c a local shop sells 30% for ~$9-11/gallon in a very nice, heavy duty HDPE carboy jug (retail
$3-5 each for the carboy alone!). These used to be 35%, IDK why it dropped to 30%. Then there are 20, 55 & 275 gallon drums/totes available of
35% for $70, $170 & $600 respectively. You can also order 50% in these sizes if (drums) when they do a restocking of the the normally stocked
35%.
I've found Ca(OH)2 available at all feed stores in 50lb bags VERY inexpensively ($6-12 depending). This is also available at building supply &
mainly lumber stores - not Home Depot/Lowes, but locally owned lumber stores. IIRC, it is a primary component of plaster and maybe stucco. CaCO3
will ALWAYS be available and I'd imagine it can be reduced to CaO in a forge. I'm going to check out local quarries b/c they mine limestone here and
they also have concrete plants on site where they burn old tires & plastics to produce the massive amounts of heat required for the reduction.
I'd be interested to see if pure CaO can be purchased directly at the quarry, which I suspect it can as it's the only component of concrete that can't
be sourced closer to construction (sand, stone, water). IDK if they only make portland cement (CaO, CaSO4 & Al2O3 - all anhydrous) or if they do
batches or pure CaCO3.
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