The Home Scientist 014 - Cheap Sulfuric Acid, Part II

[ScienceTry]

This might sound stupid, but are you NurdRage? I mean, if you edit your voice like he does, you sound EXACTLY like him.

[stefen7077]

What a great video! Thanks for making it.

[acemeister666]

rooto has something in it... on heating, it turns dark brown.

[gleepdiddly]

Wow!

[dukilaki]

so that is why i didnt get sulfuric acid burn when i splited it on my skin.

[dstnlockwood77]

can you show how to make nitric acid please that would be really helsetll. thanks

[98JMA]

What solvent do you use for your phenolphthalein?? I have it in powder form but when dissolve it in ethanol or water it doesn't work properly - both acids and alkalis are colourless!!

[TheHomeScientist]

@98JMA

Whatever you have, it doesn't sound like phenolphthalein, if you can dissolve it in water. Phenolphthalein is pretty freely soluble in ethanol or isopropanol, but nearly insoluble in water.

I generally make up 100 mL or so at a time by dissolving a gram or two of the solid in 50 mL or so of 91% or 99% isopropanol and making up to 100 mL with DW.

[Arsonomega]

I have a suggestion for your future videos.... When your listing off numbers It would be very helpful to display them on the screen lets say in the empty space to our right.... (your left) that way it would be easier to follow what your talking about...

[lexichronicle2]

i like the mention of reusing it. that's a good philosophy to get into right from the beginning. e.g. your reaction is spewing off hydrogen chloride, great. dissolve it in water, get some pure hydrochloric back with the same stone. i'm not sure if I should really be suggesting this, but you can clean up dirty sulphuric with peroxide. that requires a fair bit of know how to avoid burning your eyes out / the glass exploding. then there's distillation. nasty and not beginner level at all

[edgeeffect]

Excellent video! I've been a fan of Nurd Rage for some time and it's great to, not only see stuff that comes up to their quality, but exceeds it. So much better than all the poor quality un-narrated chemistry vids on YouTube.

[salsburyp]

One small source of possible error would be the weight of the NaOH, which is extremely hygroscopic and would slowly gain weight as it draws water vapor from the air. If this is a centigram scale, that may not be noticeable in the small amount of time, but on my milligram balance, I can watch the weight increase second by second, which makes weighing NaOH tricky. Usually need to do it in solution.

Overall, a great 2-part video! Thanks, Robert! :-)

[TheHomeScientist]

@salsburyp

Thanks for the kind words. Yes, NaOH is extremely hygroscopic. The other obnoxious thing about it is that it absorbs CO2 from the air, producing sodium carbonate. When I'm doing critical work, I generally dry the NaOH in an oven and weigh it warm. I still standardize it, though.

[salsburyp]

@TheHomeScientist And doesn't sodium carbonate further absorb CO2 to make sodium bicarbonate? Does that mean that if left alone in the open air, NaOH would eventually become pure baking soda?

[TheHomeScientist]

@salsburyp

No, Na2CO3 is stable. In fact, it's a primary standard. The only problem with it is that it has multiple hydration states. The anhydrous form absorbs water from the air to form the monohydrate. The common decahydrate efflouresces to form the monohydrate.

[salsburyp]

@TheHomeScientist Aha. I was confusing it with NaHCO3 , sorry.

Off now to read about it on wikipedia... :-)

[PyroPortrayal]

@TheHomeScientist

May I ask where you got that nice scale?

[chemy999]

@salsburyp bicarbonate means hydrogen carbonate, not two carbonates, that would be dicarbonate

[TheBombBros]

very nice! i learned alot just from this video! i put my hands together for this fantastic video. :)

[bdonlan]

You said you were going to keep the sodium sulfate at the end, but doesn't the phenolthaelin contaminate it?

[TheHomeScientist]

Sure it does. But the phenolphthalein solution is 1% w/v, so there's 1 gram of phenolphthalein per 100 mL of solution, or 10 mg/mL. One drop is about 1/20 of a mL, so there's half a milligram or 500 micrograms in that drop. That's a pretty low level of contamination.

[Neilidity]

Hi, great videos, with good info content.

One suggestion I have for you is to adjust the sound: at present, I get your voice only through my Left headphone speaker. Could you adjust your videos so that the sound goes through both channels? (it needn't be stereo, just put the same sound channel through both L and R channels).

[TheHomeScientist]

Thanks for the kind words. I've fixed the sound problem on later videos, but I'm going to leave the earlier ones as is. Fixing them would require reshooting and re-editing, and it typically takes me about one hour of actual work per minute of finished video. Rather than spend that fixing a minor problem on earlier ones, I'll spend it doing new ones.

[Neilidity]

OK, fair enough - I am not yet video-capable so I don't know how much work needs to go into them. Thanks for letting me know.

[oheeohkillertofu]

This is a great video, thanks for sharing!

[Sillybillydilly]

I dislike indirect, infinit-infinity=0.3 type measurements. Wouldn't it be more accurate to actually slowly vaporize off 10-30 grams of the sulfuric acid in a distillation rig, and catch it in a bucket of water? Is there an electric hotplate that can be enclosed inside a glass pot, and air blown through it with an aquarium pump to vent the vapors into the bucket? If boiling is avoided the results are more accurate. That way you can actually look at the residue, and analyze what it is.

[Desovamed]

what kind of scale was that?

[TheHomeScientist]

A Jennings JS200V.

[isaisai9192]

ok this is totally off subject i love science but why do this kinda thing IN A KITCHEN ?

[TheHomeScientist]

Why not? The stuff is intended to be poured down the drain, after all. Home chemists need chemicals, and this is an excellent source of inexpensive, relatively pure sulfuric acid.

Loving science in an abstract sense is great, but someone who loves science and wants to do hands-on science needs the materials to do it. That's part of what this channel is about.

[mewrox99]

@isaisai9192

That is the kitchen in the guest house which is only used for experiments

[chevon1920]

That's interesting and all, but what on earth do you need sulfuric acid at home for?

[TheHomeScientist]

Primarily as a precursor for synthesizing other chemicals, but also as a general lab reagent and as a component of various specialized test reagents.

[aCagedApe]

I liked this video but I didn't catch how much water was in the original sulfuric acid sample. I caught the weight of the dissolved solids but I'm not sure if you mentioned how much water was present. Would you help me out with that?

[TheHomeScientist]

My sample was about 96% sulfuric acid and maybe 0.25% dissolved solids. That means water made up something under 4% of the original sample.

[ILikeWeatherGuy]

@TheHomeScientist youre going a great job! im learning so much right now lol

[eveningniteshade]

Is it possible to use hardware store sodium hydroxide used for clearing drains. usually called caustic soda or lye. Would there be expected impurities that would cause failure with this experiment?

[TheHomeScientist]

Sure, you can make up the titrant with hardware store sodium hydroxide, but no matter what source you use for sodium hydroxide you'll need to standardize the titrant first if you want accurate results. Sodium hydroxide and its solutions react with atmospheric carbon dioxide to produce sodium carbonate.

[mV33rs]

Maybe you could summarize the calculations in the more info tab.

[TheHomeScientist]

That's a good idea. I'm still getting the hang of all this YouTube stuff.

[ytmachx]

I was getting lost in a blur of numbers in the end there, however, I am impressed with the purity of this "off the shelf acid". I think maybe I'll go pick some up.

[TheHomeScientist]

Of course, the problem with technical grade chemicals is that, by definition, you never know exactly what's in them or how much variance there'll be from one lot to the next. Practically speaking, I suspect there won't be all that much difference between one bottle of Rooto and another, but the only way to know for sure is to test your own sample.

[atourdeforce]

ha haha!!, RBT, you ate totally copying Nurdrange at the end "please rate subscribe and comment" lol, but i still love your show its brilliant, lets see even more show, i wanna see as many shows a week that is humanly possible??

[TheHomeScientist]

They say imitation is the sincerest form of flattery, and NurdRage does really good stuff.

I'll try to shoot two or three segments a week, but I can't promise that. I'm finding that one minute of video translates to an hour or more of total work, counting preliminaries, shooting and reshooting, editing, and so on, so basically an eight minute video costs me about a full day's work.

[DeepThroatBlood666]

Pretty awesome doc :)

Chemistry <3

[RyuSujin]

I love watching your videos! You are a true scientist sir. Cheers.

[blacksilkblacksilk]

Where have you been - and your channel - back in my university days?

U studied physics, but we had three semesters of chemstry lab work, that I barely survived. Your clips would have helped me so much. You actually explain what`s going on in terms that can be understood, so one can actually learn from them.

I very much hope that many students will benefit from your channel.

have a nice day

silk

;-))

[BrotherBloat]

I'm so glad I found this channel through the NurdRage channel. Another vid well done, THS!

[pyropakman]

great video!

[mewrox99]

So with diprotic acids you use double the amount of base.

[pyropakman]

@mewrox99 YEP!

[coolliger]

great vid

[ziggypopula123]

i do a level chemistry and im known as the chem god all thanks to this channel :D awesome!!

[jbohbot1]

excellent work, as usual and 5*. best channel ever.

[nyarvin]

If you protected the residual sodium hydroxide from absorbing water from the air (and from the steam coming up from the mixture), you could probably get the estimate for dissolved solids even lower.

[TheHomeScientist]

Doubtless, although the NaOH didn't have much time to absorb water from the air, which is pretty dry right now anyway. There wasn't any steam to speak of when I was adding the NaOH. If I'd wanted to be really accurate, I would have re-standardized some NaOH solution and done a formal titration, but I was just looking for a reasonably good number. I'd estimate 0.25% TDS, and perhaps as little as 0.2%. At any rate, I'd consider that acid to be lab grade.

[TheHomeScientist]

Yes.

[josephagp]

sweet thanks dude.

[AGDemo]

Great Vids A++ Thank you! Keep up the good work!

[bamboo4tameshigiri]

Excellent work.