Testing the Testing of Mogas

"Jay Honeck" wrote in message
oups.com...
Plop-plop, fizz-fizz... :-)

In a previous thread I outlined the new (vastly more convenient)
"alka-seltzer method" of testing your mogas for both ethanol and water
-- but (for those who missed it) here it is again:

1. Tap a few ounces of suspect gas into a cup
2. Drop 1/4 of an alka-seltzer into the gas
3. If no fizz, no alcohol or water is present, and the gas is "good"

The question was/is: Is it chemically valid to expect alka-seltzer to
fizz in the presence of alcohol?

Mary (with her minor in chemistry) and I (with my English degree that
allows me to, er, write about this) devised the following empirical
test:

Part I:

1. Purchase a bottle of 95% pure isopropyl (rubbing) alcohol. While
it's not ethanol, Mary determined that the chemical make-up is similar
enough for this test.

2. Pour a few ounces into a cup.

3. Add 1/4 tablet alka-seltzer to the alchohol.

4. Observe results.

** Sure enough, the tablet instantly starting fizzing.**

Part II:

1. Go to gas station we always buy our gas from.

2. Pump a few ounces into a cup.

3. Add 1/4 tablet alka-seltzer to the cup.

4. Observe results.

** Sure enough, the tablet just sat there -- no fizz.**

Part III:

1. Add some alchohol to aforementioned cup of gas, approximating a 10%
mixture.

2. Observe results.

** Sure enough, the tablet instantly started fizzing, verifying that it
WOULD fizz if there were alcohol in the gas. **

There are a few questions yet to answer

1. Since isopropyl alchohol is 95% pure, that means that it is 5%
water. Is the tablet fizzing only because of the 5% water?

2. However, even if this were the case, would it not also be true that
the presence of ethanol in the car gas would ALSO introduce water, and
thus fizz the alka-seltzer regardless? In other words, is it
irrelevant that the alka-seltzer might only be fizzing because of the
water, if water always accompanies alcohol in gas?

Either way, the fizzing would indicate the presence of water OR
alcohol, or just alcohol that is "saturated" with water -- both of
which would indicate a "No Buy".

Right?
--
Jay
others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. Try 9 parts of fuel to 1 part of water in a
graduated cylinder. the alcohol will migrate to the water phase so you will
see an increase in the height of the water layer at the bottom and a
decrease in the height of the fuel layer if there is significant amount of
alcohol..
terry

And for all you wannabe chemists out there... Denatured alcohol
(ethanol plus a bit of methanol) is available everywhere... I have a
quart stting in front of me on my desk I picked up at the hardware
store... I use it for cleaning my glasses, camera lenses, etc..

Get 100 cc of gasoline, add 10 cc of denatured alcohol from your
favorite Home Depot, etc., add 1/4 tab of "plop, plop, fizz, fizz" and
observe... If it fizzes then you know that the test is valid as your
mixture is "gasohol"...

denny - minor in B.S., major in Obfuscation...

I believe a number of different chemicals are used to denature ethanol.
Benzene for one.


Denny wrote:
And for all you wannabe chemists out there... Denatured alcohol
(ethanol plus a bit of methanol) is available everywhere... I have a
quart stting in front of me on my desk I picked up at the hardware
store... I use it for cleaning my glasses, camera lenses, etc..

Get 100 cc of gasoline, add 10 cc of denatured alcohol from your
favorite Home Depot, etc., add 1/4 tab of "plop, plop, fizz, fizz" and
observe... If it fizzes then you know that the test is valid as your
mixture is "gasohol"...

denny - minor in B.S., major in Obfuscation...

"Skywise" wrote in message
...
"Crash Lander" wrote in
:

Not at all a scientific type person, so this may be a dumb question, but
is there any way to evaporate the water out of the isopropyl alcohol
without burning off the alcohol, or is the evaporation point of the
alcohol lower than that of the water? If so, could you evaporate the
alcohol out of the water, and collect the pure alcohol that way?
Crash Lander

Having just read up on isopropyl alcohol the other day for other
reasons, I can help answer this....

[warning! I may have gone overboard on the info]


snip good stuff...

...which are dissolved...in a glass of water. As the tablets
dissolve, the acid and bicarbonate react vigorously producing
carbon dioxide gas


Oh No, Greenhouse Gas Warning, Global warming!




Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?


Thanks Brian. This is the neatest part of usenet. Someone out there has the
answer.

Al G

others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. Try 9 parts of fuel to 1 part of water in a
graduated cylinder. the alcohol will migrate to the water phase so you will
see an increase in the height of the water layer at the bottom and a
decrease in the height of the fuel layer if there is significant amount of
alcohol..

Thanks, but this is precisely the test procedure I'm trying to
eliminate.

Carrying water around in "The Mighty Grape", and sitting at my gas
station pumps while pouring water and gas into a beaker, and shaking
it, is just too much of a pain. People in line behind me must really
wonder what the HECK I am doing! :-)

If I can get away with simply dropping a tablet in the beaker, I will
(a) eliminate the water, and (b) speed things up considerably.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"d&tm" wrote in message
...
others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. [...]

I'm guessing you didn't see the earlier thread, but...your procedure is
where this all started. Jay even referenced it in his previous Alka-Seltzer
thread, when he wrote:

we have used the "water/gas/shake" test to verify that
there is no ethanol present. I find this method to be
rather imprecise and quite a pain

So, here's a gentle "yes, we already know" in reply to your suggestion.

Jay is attempting to come up with a test that is more foolproof, easier,
less messy, whatever.

Personally, I'm not sure that even if the Alka-Seltzer method works, it's
superior to the water-mixing method. After all, if you test by mixing
water, you just have gasahol with some water in it. You can even strain the
water out using a GATS jar if you want to use it (if the test is positive,
then in something that can tolerate ethanol, of course...like your car). If
you test it with Alka-Seltzer, now you've contaminated your fuel with an
Alka-Seltzer tablet. At the very least, you've a fuel-soaked tablet you
need to dispose of, and I'm not sure that the fuel is usable at that point,
ethanol or not. Just because the tablet didn't fizz, that doesn't mean
there aren't bits of it in the fuel.

Assuming this doesn't already exist, I think it's only a matter of time
before you can buy a fuel testing kit that is either just strips you dip
into a fuel sample, or drops you drip into a fuel sample, and which tells
you with a change of color whether there is ethanol or not in the fuel.
Either the water mixing OR the Alka-Seltzer just seems too unwieldy to me to
be practical in the long run.

Pete

In article ,
Skywise wrote:

the isopropanol solubilizes the water in the gasoline.

solubilizes.... Now that, is an interesting word!

In article om,
"Jay Honeck" wrote:

Carrying water around in "The Mighty Grape", and sitting at my gas
station pumps while pouring water and gas into a beaker, and shaking
it, is just too much of a pain. People in line behind me must really
wonder what the HECK I am doing! :-)
If I can get away with simply dropping a tablet in the beaker, I will
(a) eliminate the water, and (b) speed things up considerably.

After performing the test, and the fizzing commences, pour the contest
of the test tube into your tank. When they ask you what you are doing,
tell them you have discovered a magic tablet that allows you to put
water and the tablet in your tank and make your own gasoline. What they
saw you doing was testing to make certain you had the correct
proportions.

"Peter Duniho" wrote
If
you test it with Alka-Seltzer, now you've contaminated your fuel with an
Alka-Seltzer tablet. At the very least, you've a fuel-soaked tablet you
need to dispose of, and I'm not sure that the fuel is usable at that
point,
ethanol or not. Just because the tablet didn't fizz, that doesn't mean
there aren't bits of it in the fuel.

I would take an alka seltzer tablet, break it up and mix it in some fuel as
good as you can, and try it in your lawn mower. I'll bet that it wouldn't
miss a beat. If an engine can take that, surely a funnel with a filter
screen will catch all the significant chunks.

As far as the dud soaked alka seltzer tablet goes, Jay needs to soak one in
pure gas, and see if it will still alert on alcohol a few days later. If it
does, all he has to do is keep a small jar around to keep the soaked tablet
in, to use for the next purchase.
--
Jim in NC

Assuming this doesn't already exist, I think it's only a matter of time
before you can buy a fuel testing kit that is either just strips you dip
into a fuel sample, or drops you drip into a fuel sample, and which tells
you with a change of color whether there is ethanol or not in the fuel.
Either the water mixing OR the Alka-Seltzer just seems too unwieldy to me to
be practical in the long run.

Yeah, the ultimate would be a kit not unlike our pool-testing kit at
the hotel. Dip a little bit of litmus paper (or whatever it's called)
into the gas, and watch for a color change.

Invent one, Edison!

:-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"