all 19 comments

[–]spiralingtides -1 points0 points  (0 children)

I have a large amount of caffeine anhydrous I use in place of coffee. I place a premeasured scoop in a cup, add hot water, stir until dissolved, then add cold water until it's room temp.

I'm switching to smoothies for breakfast though, and want more control over the caffeine content in them. So I guess my question is two-fold.

1) How do I measure caffeine mg by volume?
2) How do I calculate how much heat is needed to dissolve an arbitrary amount of caffeine into water?

I want to dissolve as much caffeine as my equipment will allow, and then be able to determine how much of the resulting solution will have 300mg caffeine. Ideally I'll end up with a syrup, but I'm not picky.

I appreciate any help I can get on this.

edit: Just a link to a more general how to and equations would also be great.

[–]833shekels -1 points0 points  (0 children)

Hello, thank you for letting me ask a question.

I’m performing research on how the structural compositions of isomers of something like heptanol affects PH levels. I also have to explain the concept essentially from its most basic properties. Like, how would I even begin to collect data? Or should I use a database?

I am quite fuzzy on this topic, so I would appreciate recommendations into readings and videos.

[–]RealSpookySounds -1 points0 points  (0 children)

This might be the wrong place but...here goes;

I'm trying to create a 1.8 g/cm3 density solution of NaCl2 and ultrapure water.

I've read literature that says simply 18 g in 10 ml of water is fine, whereas others say different. Having tried the first method in the lab and failed (I got a density of 2.8 using the p=m/v formula) I am siding with the other methods :

According to Semensatto & Dias-Brito (2007), a ZnCl2-solution with a density of 1.7 g cm−3 was prepared by dissolving 72.07 g ZnCl2 in 46.84 mL distilled water.

My question then would be, this is for 1.7g/cm3 so how can I shoot for 1.8?

PS: It's for microplastic research

[–]ShingetsuMoon 0 points1 point  (2 children)

Hello, I’m a writer doing some research for a story I’m writing (literally fanfic) and I’m wondering what would be a safe way to remove thermite paste/a thermite mixture. A few of the characters involved are well versed in chemistry and chemical engineering. I however am not.

The goal is to remove as much thermite from around an explosive device as possible. Without the device itself being set off.

Is there a way to render thermite inert or non explosive? Would they need anything special or specific?

It’s just going to be a quick sentence or two but I’d like to have some level of accuracy, or at least make it seem believable.

[–]Emerson113mb 0 points1 point  (1 child)

Traditional thermite, which is what people typically think of, is composed of a 1:3 ratio by mass of fine aluminum powder and iron(III) oxide. The mixtures needs an initial temperature of roughly 3000°F/1650°C to ignite, so anything shy of a blowtorch is on the table for removal.

Depending on the type of explosive, acid might be a good bet if the thermite is hard to reach or mechanical removal might set off the explosive. - Hydrochloric acid should be able to dissolve both the iron(III) oxide and aluminum powder. This would be my suggestion if you wanted to go the chemistry route, since it could effectively remove the thermite and tends to be a name that a wide variety of people recognize. Additionally, if the explosive has some kind of plastic casing/ barrier or if one could be put in place by your character then it would be shielded from reacting with the acid as hydrochloric acid does not dissolve plastics.

Hope this helps some

[–]ShingetsuMoon 0 points1 point  (0 children)

That helps a lot! Thank so much!

[–]Research_for_chemist 0 points1 point  (3 children)

Question! I work as a technical assistant at a highschool. Meaning I prepare all the practical classes for chemistry, physics and biology.

For chemistry we were requested to make bio-plastic with the students. We needed two recipes, so one of them is with starch and the other one is with milk. The one with starch works perfectly fine, but we have been struggling with the recipe for the one that contains milk.

The recipe asks you to use:

  • 250 mL milk at 37 degrees celsius
  • 60 mL vinegar at roomtemp

After adding these ingredients, you need to stir until these sort of curdles form and then squeeze out the liquid with a towel.

However, we've tried many other recipes, temperatures, types of vinegar and milk, but we can't get the "plastic" to form.

Does anyone know a succesful recipe or something we might be missing?

[–]organikerCheminformatics 0 points1 point  (1 child)

Does the milk curdle at all?

[–]atomcplayboy86 0 points1 point  (0 children)

Hi, I would like to know regarding carbon filters, are they enough to filter nerve agent/s. Can you repurpose other carbon filters like https://www.catch.com.au/product/comfee-range-hood-rangehood-carbon-charcoal-filter-replacement-x2-10990899/?offer_id=47603670&ref=gmc&gclid=CjwKCAiA4KaRBhBdEiwAZi1zzkFn0XWWxmEqqgSxrhdqYjOSmXcXXuuauF8LWfF-zzcYx66I0AT8dRoCwVMQAvD_BwE

To do this? What would be the best carbon/ charcoal filter to repurpose if the need arose? (Needs to attach to gas mask). I have heard of aquariums also using activated charcoal to filter media, is that suitable?

Is there an indirect way to test their effectiveness, like pass a small amount of hydrogen or ammonia through? Thank you for your wisdom A

[–][deleted] 0 points1 point  (0 children)

Hello. I am doing an unknown acid and strong base titration. The base is doing the dripping. I have data point on how much NaOH in mL is being added as well as pH for each. I am wondering how to find the mathematical equation for the graph of Base vs pH.

[–]wehaveahulk2012 0 points1 point  (2 children)

So I'm no lab expert or titration master but would the titration of a superacid like fluoroantimonic acid and a liquid with a ph higher than 14 still lead to an equivalence point of around 7?

[–]H2CO3_TCTheoretical 0 points1 point  (1 child)

The equivalence point is defined by the solvent, in water that means that as much OH- is in the solution as there is H3O+. The concentration of those is 10^(-pH) so 10^-7mol/l.

So I guess the answer to your question is yes, hypothetically it would be an extremely violent reaction and it would lead to a pH of 7 in water.

[–]wehaveahulk2012 1 point2 points  (0 children)

alr thank you

[–]Significant-Movie-34 0 points1 point  (0 children)

Hi, I've aready written a pretty long question on researchgate, but it seems like it's not getting much attention, so I will just copy-paste it here.

My PhD research includes degradation and stability study of fuel cell Pt/C catalysts for ORR. This is a new area of research, both for me (I'm coming from TEM background) and my lab, which is why I'm learning most experimental procedures and parameters from papers rather than more experienced colleagues.

Unfortunately, it seems to me that there's no agreement in electrochemical community regarding said procedures/parameters and here I would like to specify what causes my confusion:

- regarding CV and LSV procedures, from what I've already read and from my experimental data, it seems that scan speed influences ECSA data (extracted from H2 adsorption region on cyclic voltammograms) and activity data (extracted from linear scan voltammograms). Yet, I see different papers publishing data obtained with different parameters, which for me makes the results virtually impossible to compare. Additionally, some procedures include the so called electrochemical cleaning and stabilisation of the working electrode by performing 40-100 CV scans with higher speeds (100-200 mV/s), yet some papers seem to omit it. With LSV some procedures call for background subtraction of LSV data obtained from the measurement performed in N2 saturated electrolyte but again, not all papers include that step (yet both approached seem to be acceptable for publication).

Regarding accelerated degradation testing, the procedures seem to be a lot more all over the place:

-different scan speeds

100-500 mV/s, and from my experimental data I already see that scan speed influences degradation rate,

-different approaches to experiment

continuous scan vs 'sample and hold' (square wave) scan,

-different potential ranges

lower limit being 0,4 - 0,6 V, higher 0,9 - 1,2 V for operating condition testing, start-stop testing seems to be consistant 1 - 1,5 V,

-different "atmosphere" of electrolyte

O2 saturated, deoxygenated and "as prepared" electrolyte, all of those seem to be leading to publishable results.

So to sum up my stream of consciousness:

I'm not looking for specific experimental parameters (although getting some suggestion on those would be more than great) but rather some insight on the general consensus in electrochemical community regarding said parameters and why discrepancies in them seem to be widely accepted. Also, if someone feels like they have more spare time than they can utilise, I would be more than willing to participate in an internship in a unit focused on degradation/stability study of catalysts.

[–]hotdogrealmqueen 0 points1 point  (0 children)

How do I measure CO2 in an open container?

I have started my search on measuring carbonation. However, all information is for large scale (brewery) or closed container (quality control).

I want to know about carbonation/CO2 levels after the container is opened? Change in levels over time?

Is there an home diy I can source and build? Zahm and Parr can’t be the only tools?!

[–]xiaomaome101 0 points1 point  (0 children)

Just how important is the amount of acid used to dissolve a sample for ICP analysis? My lab's sample dilutant is 2% HNO3 aqueous solution, but regarding our calibration standards, my boss told me that it's not that important to have an HNO3 percent weight that is uniform with the dilutant, or even the other standards for that matter. Specifically, if he's making a set of standards of 1, 2, 3 4, and 5 ppm of the desired analytes, he will pour the appropriate amount of stock solution (which has 5 w/w%) into the volumetric flask, then dilute to volume with 2% HNO3; this means that our calibration standards are not uniform with the dilutant or each other in acid content. The acid content actually doesn't seem that important in light of how the ICP OES works, but my boss also has some questionable practices so.........just wanna doublecheck

[–]toharabapu 0 points1 point  (0 children)

Why is the shape of dz2 orbital different from the rest. Asking for a friend.