Pour water into acid?
michel
Hello, I keep forgetting, should we pour water into acid or
acid into water?
Is there an easy way to remember this?
Thank you, Michel.
Jeff E. Janes
Do as you oughta', add acid to wata'.
Or do it wrong a few times, you'll start to remember it....
Jeff
Bob Bruner
Add acid to water. Acid is dangerous. By adding acid to water
(slowly), the mixing involves only a little bit of the dangerous
stuff.
bob
Uncle Al
michel wrote:
>
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
>
> Is there an easy way to remember this?
>
> Thank you, Michel.
Protonation of water is tremendously exothermic. Pour water into
concentrated acid and it may flash into steam.
There lies a chemist so cool and placid,
He poured the water into the acid.
He'd be alive if he done what he oughta.
Always pour the acid into the water.
(Rhymes in New York, sorta.)
Pouring concentrated acid onto an equal volume or greater of crushed
distilled water ice with mixing works nicely.
--
Uncle Al Schwartz
Uncl...@ix.netcom.com ("zero" before @)
http://pw2.netcom.com/~uncleal0/uncleal.htm
http://www.ultra.net.au/~wisby/uncleal.htm
http://www.guyy.demon.co.uk/uncleal/uncleal.htm
(Toxic URLs! Unsafe for children, Democrats, and most mammals)
"Quis custodiet ipsos custodes?" The Net!
Phillip M Edwards
On Sat, 24 Jan 1998 16:19:10 -0800, michel <dup...@total.net> wrote:
Well, it's generally believed that acid should be poured into water. If
not (say that you forget the order), you're in for a potentially nasty
surprise, as the mixture quite often tends to bubble over. For this
reason, it's pretty vital that you just take the time to memorize this
rule of thumb.
hboyter
And don't forget that the same holds true for bases also. It also holds
true for other concentrated chemicals (usually powders) such as
hydrosulfite.
--
Dr. Henry Boyter, Jr.
Ph.D. Chemist
The opinions of Dr. Boyter are provided for informational purposes only and
should not be used as advice. No warranty or expression of professionalism
is implied.
Phillip M Edwards <pedw...@acsu.buffalo.edu> wrote in article
<34ca7ef9...@news.buffalo.edu>...
Joel no-XYZZY Polowin
michel wrote:
>
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
>
> Is there an easy way to remember this?
For me, the "easy way to remember" things is to understand *why*
they do what they do. In this case, you're talking about mixing
two substances in a highly exothermic reaction. If one of the
substances has a much lower boiling point than the other, adding
a small amount of the low-boiling substance to the high-boiling
substance is much more likely to cause local boiling and spattering
than adding a small amount of the high-boiling substance to the
low-boiling substance.
If you're talking about concentrated sulfuric acid and water,
the acid has a much higher boiling point, so you add the acid to
the water. If you're talking about most other acids, or about
dilute sulfuric acid, the reaction is much less exothermic, so
it doesn't matter which is added to which. If you're mixing
solid sodium hydroxide with water, again, you add the hydroxide
to the water. If you're mixing concentrated aqueous solutions
of strong acid and strong base, it doesn't matter much which
way you add them, since they both present the same spattering
risk -- you just have to try to do it carefully either way,
or better yet, find some other way of doing the reaction.
--
Joel Polowin
jpolow...@cyberus.ca but delete "XYZZY" from address
Just a little magic to beat the spambots...
Eric Lucas
Uncle Al wrote:
> There lies a chemist so cool and placid,
> He poured the water into the acid.
> He'd be alive if he done what he oughta.
> Always pour the acid into the water.
>
> (Rhymes in New York, sorta.)
And Boston, which gave up its "r" sounds, so that New York might have
extra.
Eric Lucas
lwax
Do as you oughta, add acid to watta
michel <dup...@total.net> wrote in article <34CA84...@total.net>...
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
>
> Is there an easy way to remember this?
>
> Thank you, Michel.
>
jesc...@erols.com
Bob Bruner wrote:
>
> Add acid to water. Acid is dangerous. By adding acid to water
> (slowly), the mixing involves only a little bit of the dangerous
> stuff.
>
> bob
>
> And don't forget that the same holds true for bases also. It also holds
> true for other concentrated chemicals (usually powders) such as
> hydrosulfite.
> --
> Dr. Henry Boyter, Jr.
Some excellent points. Also remember that when you pour one liquid into
a container that has a different liquid in it, the liquid you are
pouring in has downward momentum at the surface (where splashing will
occur). This means that any splashes that do occur will have a very
high concentration of the material that was sitting in the container
already. Of course, if the container had very little in it initially,
the added liquid rebounding off the bottom of the container will be more
significant and the inertia arguement is less important. (The chemical
reaction arguements are probably about the same, though.)
As a general rule, I would add the more dangerous chemical to the less
dangerous one unless the system of interest was much more likely to boil
or splash that way. You can also add the liquid slowly while pouring it
down the inside wall of the container while mixing to reduce splashing
if the system is particularly prone to such things.
--
Understanding is a three edged sword-
your side, my side, and the truth.
Greg
On Sat, 24 Jan 1998 16:19:10 -0800, michel <dup...@total.net> wrote:
>Hello, I keep forgetting, should we pour water into acid or
>acid into water?
>
>Is there an easy way to remember this?
>
>Thank you, Michel.
Water in acid, you're blasted.
Acid in water, you got 'er.
Jim Thomson
If your doing what you otter
you add the acid to the water
if you add the water to the acid.
michel wrote in message <34CA84...@total.net>...
Scott Mohler
michel wrote:
>
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
>
> Is there an easy way to remember this?
>
> Thank you, Michel.
Always Add Acid
three 'A's
-Scott Mohler
Richard Kinch
michel <dup...@total.net> wrote:
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
Think of the acid as hot oil in a deep fryer.
Think what happens when a drop of water falls in that oil.
Ted Mooney
Jim Thomson wrote:
>
> If your doing what you otter
> you add the acid to the water
> may your rest be long and placid
> if you add the water to the acid.
>
> michel wrote in message <34CA84...@total.net>...
> >acid into water?
> >
> >
> >Thank you, Michel.
Poems and stuff are great for remembering rather arbitrary lists like
how many days each month has, but I think a mental picture that explains
"why" may be best in this case. I picture this big vat of ugly oily
acid, a drop of water sliding out of an eyedropper into it, and the heat
flashing that droplet into a bomb of steam.
Marc Tobback
Always be carefull: when you pour acid in water, this mixture can become
very hot and can even boil!
Scott Mohler wrote in message <34CC95...@abbott.com>...
>michel wrote:
>>
>> Hello, I keep forgetting, should we pour water into acid or
>> acid into water?
>>
>> Is there an easy way to remember this?
>>
>> Thank you, Michel.
>
Jeff E. Janes
Richard Kinch wrote:
>
> michel <dup...@total.net> wrote:
>
> > Hello, I keep forgetting, should we pour water into acid or
> > acid into water?
>
>
> Think what happens when a drop of water falls in that oil.
What if I think of the water as hot oil in a deep fryer?
It seems like a symmetrical situation.
Jeff
Jim Thomson
I learned the rhyme from my chemistry teacher in high school more than 20
years ago. It is simplistic but it sticks. My point in repeating it was to
give the original poster something to remember.
Ted Mooney wrote in message <34CE2E...@intac.com>...
>Jim Thomson wrote:
>>
>> If your doing what you otter
>> you add the acid to the water
>> may your rest be long and placid
>> if you add the water to the acid.
>>
>> michel wrote in message <34CA84...@total.net>...
>> >Hello, I keep forgetting, should we pour water into acid or
>> >acid into water?
>> >
>> >Is there an easy way to remember this?
>> >
>> >Thank you, Michel.
>
Richard Kinch
Jeff E. Janes <jej...@silibone.cchem.berkeley.edu> wrote:
> Richard Kinch wrote:
> >
> > michel <dup...@total.net> wrote:
> >
> > > Hello, I keep forgetting, should we pour water into acid or
> > > acid into water?
> >
> > Think of the acid as hot oil in a deep fryer.
> >
> > Think what happens when a drop of water falls in that oil.
> What if I think of the water as hot oil in a deep fryer?
> It seems like a symmetrical situation.
But it isn't symmetrical. The drop of water in the cooking scenario
is the water in the chemistry scenario.
I think of (certain) acids as oily or syrupy. Foods to be fried are watery.
So the hot oil is acid.
You do have to think about it, so it is more effort than rote rhymes,
and liable to errors of casual thinking. If it is not obvious, it is by
definition not a trustworthy mnemonic.
Richard Kinch
michel <dup...@total.net> wrote:
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
Another mnemonic, for swimming pool owners:
We pour HCl acid directly into our pools to balance pH.
(And I note, too often, from a squat, bare-handed, and without eye protection.)
Nola Etkin
michel wrote:
>
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
Acid into water. That way small amounts of acid are solvated by large
amounts of water. If you do it the other way around the first bit of
water won't be enough to solvate all the acid.
> Is there an easy way to remember this?
Yeah - get it wrong once - especially with conc H2SO4. Make sure the
emergency room is on standby.
> Thank you, Michel.
Nola
****************************************************
Nola Etkin
Assistant Professor of Chemistry
University of Prince Edward Island
Charlottetown, PEI, Canada C1A 4P3
Voice: 902-566-0693
FAX: 902-566-0632
e-mail: net...@upei.ca
****************************************************
R.J. Blundell
In article <34CEBF...@silibone.cchem.berkeley.edu>,
>>
>> > Hello, I keep forgetting, should we pour water into acid
or
>> > acid into water?
>>
>>
>> Think what happens when a drop of water falls in that oil.
>
>What if I think of the water as hot oil in a deep fryer?
>It seems like a symmetrical situation.
>
>
If you pour A into B, which one splashes up at you? Which
one would you rather not have splashing up into you?
Rob
Rob Blundell,
School of Chemistry,
University of Leeds,
Leeds LS6 1HP,
ENGLAND.
Tel: (+44) (0)113 233 6526
Just in case I'm talking out of my butt,
"The opinions and comments within are my own,
and should not be construed as being those of
the University of Leeds or any other member
of it."
J.J. Emerson
Greg <geb*b...@junctionnet.com> wrote in article
<34cc1154...@nntp.junctionnet.com>...
> On Sat, 24 Jan 1998 16:19:10 -0800, michel <dup...@total.net> wrote:
>
> >Hello, I keep forgetting, should we pour water into acid or
> >acid into water?
> >
> >
>
> Water in acid, you're blasted.
> Acid in water, you got 'er.
Another mnemonic device that I have found easy to remember is:
Do what you oughta,
add acid to wata
or, depending on your dialect,
Do what you oughter,
add acid to water
J.J.
Thomas Coyle
--
The simple mnemonic that I learned was:
"The water must be in before,
you add the H 2 S O 4."
KBader
Always Add Acid (AAA)
shahar stein
> > On Sat, 24 Jan 1998 16:19:10 -0800, michel <dup...@total.net> wrote:
> >
> > >Hello, I keep forgetting, should we pour water into acid or
> > >acid into water?
> > >
> > >Is there an easy way to remember this?
i think the best way is to understand what is the reasone for the
difference.
it is all a matter of concentrations.
if you pour acid into water the concentration of the acid is relatively
not very high and the heat generated is spread evenly and slowly.
if you are unfortunate and make a mistake you do the opposite. :-)
you add water to the acid. NOW you have a lot of conc. acid and a little
bit of water the heat created is transfered to the water and they become
SUPER-HEATED you get an --explosion-- kabum blast whatever.
not a very nice thing to happen.
just remember the WHY and you will know the HOW.
shahar stein from isreal.
biophysics is my area of intrest.
plaese remove XX from e-mail in order to reply
Rebecca M. Chamberlin
In article <34E2CD...@inter.net.il>, shahar stein
<stei...@inter.net.il> wrote:
> i think the best way is to understand what is the reasone for the
> difference.
>
> it is all a matter of concentrations.
> if you pour acid into water the concentration of the acid is relatively
> not very high and the heat generated is spread evenly and slowly.
Ahhhh... and now we get to the heart of the matter. If you're making, say,
8 M HCl or 10 M HNO3, does the "add acid to water rule" still apply?
Becky
David Hemmings
yes
shahar stein
Rebecca M. Chamberlin wrote:
>
> In article <34E2CD...@inter.net.il>, shahar stein
> <stei...@inter.net.il> wrote:
>
> > i think the best way is to understand what is the reasone for the
> > difference.
> >
> > it is all a matter of concentrations.
> > if you pour acid into water the concentration of the acid is relatively
> > not very high and the heat generated is spread evenly and slowly.
>
> 8 M HCl or 10 M HNO3, does the "add acid to water rule" still apply?
>
> Becky
forgive me becky for asking, but i didn't understand, what do you mean?
making it from even more conc. acid or what?
shahar
in order to reply please remove anti-spam XX from email.
Rebecca M. Chamberlin
In article <34E429...@inter.net.il>, shahar stein
<stei...@inter.net.il> wrote:
> Rebecca M. Chamberlin wrote:
> >
> > In article <34E2CD...@inter.net.il>, shahar stein
> > <stei...@inter.net.il> wrote:
> >
> > > i think the best way is to understand what is the reasone for the
> > > difference.
> > >
> > > it is all a matter of concentrations.
> > > if you pour acid into water the concentration of the acid is relatively
> > > not very high and the heat generated is spread evenly and slowly.
> >
> > Ahhhh... and now we get to the heart of the matter. If you're making, say,
> > 8 M HCl or 10 M HNO3, does the "add acid to water rule" still apply?
> >
> > Becky
>
> forgive me becky for asking, but i didn't understand, what do you mean?
> making it from even more conc. acid or what?
>
> shahar
If the aim is to provide a larger sink for the heat of mixing the acid and
water, then the "add acid to water" rule is really only appropriate when
the amount of water is larger than the amount of acid. i.e. only applies
when preparing relatively dilute acid solutions.
Using the "heat sink" argument: what's the best way to prepare a
relatively concentrated acid solution (e.g. 8 M HCl), which is based on
combining a *larger* amount of the concentrated acid with a *smaller*
amount of water?
Becky
Jan Lasse Eilertsen
Rebecca M. Chamberlin wrote:
>
> If the aim is to provide a larger sink for the heat of mixing the acid and
> water, then the "add acid to water" rule is really only appropriate when
> the amount of water is larger than the amount of acid. i.e. only applies
> when preparing relatively dilute acid solutions.
>
> Using the "heat sink" argument: what's the best way to prepare a
> relatively concentrated acid solution (e.g. 8 M HCl), which is based on
> combining a *larger* amount of the concentrated acid with a *smaller*
> amount of water?
>
> Becky
a small amount water with a larger amount of concentrated acid. The heat
is generated in the mixing zone. If this heat generation is much larger
than the heat transport, you can get boiling. The water is less dense
than the concentrated acid, and will not mix properly if you pour it
carefully. To avoid splashing, you would not throw it in, either. If you
pour acid into water, the density differense will help mixing and the
heat is spread.
Please correct me if I'm wrong.
--
Jan Lasse Eilertsen
Dpt. of Inorganic Chemistry,
The Norwegian University of Science and Technology, N-7034 Trondheim,
NORWAY.
Ph.:+47 7359 2791
http://www.chembio.ntnu.no/users/eilerts
shahar stein
Rebecca M. Chamberlin wrote:
>
> In article <34E429...@inter.net.il>, shahar stein
> <stei...@inter.net.il> wrote:
>
> > Rebecca M. Chamberlin wrote:
> > >
> > > In article <34E2CD...@inter.net.il>, shahar stein
> > > <stei...@inter.net.il> wrote:
> > >
> > > > i think the best way is to understand what is the reasone for the
> > > > difference.
> > > >
> > > > it is all a matter of concentrations.
> > > > if you pour acid into water the concentration of the acid is relatively
> > > > not very high and the heat generated is spread evenly and slowly.
> > >
> > > Ahhhh... and now we get to the heart of the matter. If you're making, say,
> > > 8 M HCl or 10 M HNO3, does the "add acid to water rule" still apply?
> > >
> > > Becky
> >
> > forgive me becky for asking, but i didn't understand, what do you mean?
> > making it from even more conc. acid or what?
> >
> > shahar
>
> water, then the "add acid to water" rule is really only appropriate when
> the amount of water is larger than the amount of acid. i.e. only applies
> when preparing relatively dilute acid solutions.
>
> Using the "heat sink" argument: what's the best way to prepare a
> relatively concentrated acid solution (e.g. 8 M HCl), which is based on
> combining a *larger* amount of the concentrated acid with a *smaller*
> amount of water?
>
> Becky
i'll make it even more complicated: what should you do if you have only
ONE drop of water to add to a glass full of acid. what then?
as you can see there might be a region in the space of concentrations
and volumes that would be safer to add the acid and a region where it
would be better to do the opposite.
that's my feeling. but on the ordinary everyday acid preperation
procedures if think it would be in most cases to put the acid inn the
water.
can anyone put forward an equation for that space, that would include
heat transfer, volumes, concentratins, etc. i think it can be intersting
*
In article <34E6CC...@inter.net.il>, shahar stein <ste...@inter.net.il>
wrote:
> >
> > Using the "heat sink" argument: what's the best way to prepare a
> > relatively concentrated acid solution (e.g. 8 M HCl), which is based on
> > combining a *larger* amount of the concentrated acid with a *smaller*
> > amount of water?
> >
> > Becky
> well if think that this is more complicated.
> i'll make it even more complicated: what should you do if you have only
> ONE drop of water to add to a glass full of acid. what then?
To me, a fair amount of this is hooey.
The heat is generated by the production of hydronium ions (source of the
well-known leveling effect)
12M HCl (or 10M) is mostly water already and the HCl is mostly 100%
ionized (not fully at 12M or 10M, I'll grant you that). So the heat
generated by the dilution to 8M is small.
One dilutes from 12 to 8 with stirring and slow adding. Should be obvious.
In 98% H2SO4 or 70% HNO3, there is relatively little hydronium, so we have
a large heat output upon dilution.
If one is adding a large amount of the two above acids to water, one can
add the water slowly (in the form of ice if so desired), with stirring and
in an ice bath if desired.
John
Mike H
In article <rmchamberlin-ya0236...@news.lanl.gov>,
Rebecca M. Chamberlin <rmcham...@lanl.gov> writes
>In article <34E2CD...@inter.net.il>, shahar stein
><stei...@inter.net.il> wrote:
>
>> i think the best way is to understand what is the reasone for the
>> difference.
>>
>> it is all a matter of concentrations.
>> if you pour acid into water the concentration of the acid is relatively
>> not very high and the heat generated is spread evenly and slowly.
>
>Ahhhh... and now we get to the heart of the matter. If you're making, say,
>8 M HCl or 10 M HNO3, does the "add acid to water rule" still apply?
>
>Becky
Well, yes....
But care is always required when dealing with any acid.
If you make 25% H2SO4 by adding acid to water it may still boil if you
do it too quickly. Even more so for stronger concentrations.
But that's still better than doing it the other way round, where the
water instantly boils very violently, and the whole lot explodes :)
Of course the effect in HCl or HNO3 is greatly reduced, but the
principle holds.
--
Mike H
"If truth equals concensus and the populace is wrong....
- I am still condemned"
N.B. Remove ".spamless" from address to reply.
Mike H
><stei...@inter.net.il> wrote:
>
>> Rebecca M. Chamberlin wrote:
>> >
>> > In article <34E2CD...@inter.net.il>, shahar stein
>> > <stei...@inter.net.il> wrote:
>> >
>> > > i think the best way is to understand what is the reasone for the
>> > > difference.
>> > >
>> > > it is all a matter of concentrations.
>> > > if you pour acid into water the concentration of the acid is relatively
>> > > not very high and the heat generated is spread evenly and slowly.
>> >
>> > Ahhhh... and now we get to the heart of the matter. If you're making, say,
>> > 8 M HCl or 10 M HNO3, does the "add acid to water rule" still apply?
>> >
>> > Becky
>>
>> making it from even more conc. acid or what?
>>
>> shahar
>
>
>If the aim is to provide a larger sink for the heat of mixing the acid and
>water, then the "add acid to water" rule is really only appropriate when
>the amount of water is larger than the amount of acid. i.e. only applies
>when preparing relatively dilute acid solutions.
>
>relatively concentrated acid solution (e.g. 8 M HCl), which is based on
>combining a *larger* amount of the concentrated acid with a *smaller*
>amount of water?
>
>Becky
NEVER add water to concentrated acid !
And still take care the mixture doesn't get too hot when adding acid to
water. Add it slowly. Use a water or ice bath to cool the vessel if
necessary (careful there too!).
You only need to get it wrong once....... :)
Joel no-XYZZY Polowin
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
>
> Is there an easy way to remember this?
For me, the "easy way to remember" things is to understand *why*
they do what they do. In this case, you're talking about mixing
two substances in a highly exothermic reaction. If one of the
substances has a much lower boiling point than the other, adding
a small amount of the low-boiling substance to the high-boiling
substance is much more likely to cause local boiling and spattering
than adding a small amount of the high-boiling substance to the
low-boiling substance.
If you're talking about concentrated sulfuric acid and water,
the acid has a much higher boiling point, so you add the acid to
the water. If you're talking about most other acids, or about
dilute sulfuric acid, the reaction is much less exothermic, so
it doesn't matter which is added to which. If you're mixing
solid sodium hydroxide with water, again, you add the hydroxide
to the water. If you're mixing concentrated aqueous solutions
of strong acid and strong base, it doesn't matter much which
way you add them, since they both present the same spattering
risk -- you just have to try to do it carefully either way,
or better yet, find some other way of doing the reaction.
--
Joel Polowin
jpolow...@cyberus.ca but delete "XYZZY" from address
Just a little magic to beat the spambots...
Fred Rea
* wrote:
> In article <34E6CC...@inter.net.il>, shahar stein <ste...@inter.net.il>
> wrote:
> ...
> If one is adding a large amount of the two above acids to water, one can
> add the water slowly (in the form of ice if so desired), with stirring and
> in an ice bath if desired.
>
> John
Part of the idea here, as I understand the reasoning, is that any splashing,
whether due to heat release or plain old sloppy pouring, will result in bulk
liquid (the addee, if you will. solvent if you won't) becoming airborn as
droplets, etc. The goal is to have the drops flying around, if they must fly
around, be mostly water rather than mostly acid.
Thus, regardless of quantities, you still want to add acid to water. The
trivial case of adding a drop of water to a beaker of acid could conceivably go
either way, but the dynamics and heat sink effect make it seem unlikely that a
deviation from standard procedure would be greatly beneficial.
If I remember freshman chemistry incorrectly, feel free to flame away. I can
only get logged on about every other week, anyway, so I'll probably miss it.
Fred.
joan maricle
NEED TO MEASURE TRANSEPITHELIAL POTENTIAL DIFFERENCE
My research project is to build a voltmeter that can measure the
movement of
ions across the surface of mucus membranes. I will pay a fee
(negotiable) to
anyone who can collaborate with me, successfully, on the building of
this
piece of equipment. Please contact me ONLY at the address below:
Chris Street
> Another mnemonic device that I have found easy to remember is:
>
>Do what you oughta,
>add acid to wata
>
>or, depending on your dialect,
>
>Do what you oughter,
>add acid to water
>
>J.J.
Do what you ought to
add acid to the water
for a reaction far less placid
add the water to the acid.
The Original MAD alCHEMIST <ch...@mithrandir.demon.co.uk>
http://www.mithrandir.demon.co.uk/index.html
79.45% of all statistics are made up on the spot.
Lepore
> Do what you oughter,
> add acid to water
(in alphabetical order)
--
M. Lepore
Delete the x in the address
Linda Hazell
> Hello, I keep forgetting, should we pour water into acid or
> acid into water?
> Is there an easy way to remember this?
Just thought I'd throw my version of the rhyme into the mix.
The liquid boils, not sits there placid,
When water’s added to the acid;
If you are wise, do what you oughta’
and put the acid in the water!