Endothermic - Chem Definition

[MegaSkills9]

I once worked with a guy that was the emotional equivalent of an endothermic reaction. He would walk into a room and suck all the fun out of it. ;-)

[Blues251]

show us how to detonate Ammonia Nitrate :D

[Theklstuff]

14.9 degrees that's a pretty cold lab

[AznAlacran]

Great video but I really don't understand an endothermic reaction. If it absorbs thermal energy wouldn't it become warmer because it's absorbing heat?

[deadlyroomsofdeath]

@AznAlacran the thermal energy absorbed goes into the process of breaking bonds in the reactants - the energy is used up, it is not still there once the products are made. When bonds are made (i.e. forming the products) energy is released.

In an endothermic reaction the amount of energy released from bond formation is less than that absorbed to break the bonds. Overall, energy is absorbed, decreasing the temperature.

Hope that helps; send me a message if you want more explanation :)

[omerta410]

less than 15 degrees? this lab is pretty cold!

[AnoushkaGold]

I though that the forward reaction in the Haber Process to make ammonia was exothermic and the backward reaction is therefore endothermic... Please correct me if I'm wrong.

[conzobonzo]

if you were to agitate the solution, would it become colder still?

[caravaggio71]

The Haber-process ist an exothermic reaktion !

[Evertonian94]

Now I know where fahrenheit came from :)

[rageagainstthebath]

@Evertonian94 You know where 0 degrees fahrenheit came from. You need to know where Fahrenheit decided to put his 100 degrees to fully understand it. I've heard that he have measured the temperature of his wife for this, who was a bit ill that day. A video on this would be pretty handy. :)

[HiyoriTamura92]

Haha, Endothermic and Exothermic, reminded me of my secondary school Chemistry lessons :D Can't believe I remember some of this stuff.

[MidnightRedemption]

two weeks from now and it will be our school trip.. i just need ammonium nitrate and water to cool off my beverages and i bet my classmates will be like "WOah!!"

[rabbitsib]

@MidnightRedemption although that sounds like a good idea, please don't drink it. Its a very dangerous idea and chemistry and food should never coincide in a lab. Of course there are some exceptions.

[02tonyl]

Thank you for the video periodicvid. I'd like to ask a question about what the professor said about zero degree farenheit, mixing snow and concentrated nitric acid. When you mix ice and concentrated acid, is it an exothermic reaction as the hydrogen bond form between the water molecule and the acid ? So does the solution not get hot instead of cold ?

[Jisse000]

I am not sure to have understood everything, but there is one thing that bothers me.... Shouldn't the glass container kind of break or explode if the temperature of its content really loses 20 degrees within a couple of seconds?

[Mike1614b]

@Jisse000  it's Pyrex, which is thermally stable glass

[champagnerocker]

The minimum working temperature in a room is 16'C, if your lab is less than that you should be on strike!

[clovelywindheaven]

so if i lit myself on fire what sort of reaction would that be....

lol lol...

[nbsr1]

Pretty cold in that lab.

[Truthiness231]

Ahh, I finally understand why 0°F isn't completely arbitrary now... I still like °C though...

[Midnighter169]

holy crap this is what happens with the baking soda and vinegar back in first grade

[HomeDistiller]

i would have to say that Fahrenheit wold have to be the strangest scale, Celsius and kelvin i can understand because they both use water but a way off blood temp and then ice plus nitric acid?? whats wrong with boiling water and ice??

[onceuponadream24]

@HomeDistiller that's so true

[DeoMachina]

So is this how they make those little chocolate cups that go cold when you eat them?

[casmatt1]

you guys should do a poll! who is your favorite scientist! :)

[periodicvideos]

@casmatt1 have you seen my other channel called favscientist

you might like it!

[boldger13]

@periodicvideos

No, I haven't. How do I find it?

[afhdfh]

@casmatt1 That'd be waaaaay too hard! They're all awesome in their own way. :)

[Eltron25]

why reactions go slower if they get cold?

[silentelysium]

@Eltron25 in order for a reaction to occur, molecules have to collide to each other for bonds to be made. You make molecules collide by applying energy (in the form of heat). Temperature is actually the average velocity in which all molecules move. So if you decrease the temperature --> average velocity of molecules decreases --> decrease no. of collisions therefore decrease rate of reaction (i.e. slower reaction).

[Eltron25]

@silentelysium i get it now. It's like the gases, that when you apply them more temp they generate more pressure on the container, but in this case the higher velocity make them collide more times and generate new molecules. Thank you very much!

[metfan89]

@Eltron25 because the atoms move slower and so they dont bump into each other often therefore making the reaction slow.

[G3org3Master]

I learnt about this recently in chemistry yr 11. Exothermic is the opposite, gives out heat or explosion!

[sharperguy]

Felis catus is your taxonomic nomenclature: an endothermic quadruped, carnivorous by nature.

[MaBuSt]

correction? : Professor says at ~ 56 seconds in that chemists care about whether heat is flowing in or out of the flask, but heat is the flow of energy, heat doesn't flow. They do care if energy flows in or out of the flask though.

sorry to be picky

[MrBCMarijuana]

Wow, what a change in temperature.

[panynja]

Hi I'm a high school student from California, and I just wanted to say I love your videos. They're informative and they have awesome demos (the alkali metals videos especially). Thanks :D

[BarneySaysHi]

Can you show the experiment that Fahrenheit did to get his lowest temperature?

[jakeweiq]

0:00-0:01 i almost saw it is as (adj) en-doh-thur-milk

gawh just woke up.

[yusukeshinyama]

I'm always curious about the smells of materials. Every time someone brings a new chemical in this video, I'm interested not only in its genuine smell, but also in the way one *describes* it. Brady, when someone shows a new chemical next time, please ask them how it smells like!

[T1carus]

gah, almost missed this to the shoddy new youtube layout

[engelteir]

So did the water you were using freeze? i would think that would make the reaction difficult?

[Findulidas]

15C in your lab. Im glad Im not using that lab, would be freezing all the time.

[ejcv093]

260 likes and no dislikes. I hope no trolls will ruin this record.

[morto360]

She is hot!!!

[shouryuuken100]

Its 15 degrees in your lab!?! Heat it up!! You guys must be freezing your socks off!

So much for 'room temperature'...

[VALKIR4636]

now get a newspaper and make smoke bombs :)

[Athiest2009]

A thermistor with a whet-stone bridge circuit would have been more accurate than the thermocouple.

[12gaugebleachdrinker]

Were can I get the ball that changes from green to almost clear that the Professor uses?

[Huapua]

Your lab is sooooo cold (15*C)!

[geeupson]

@Huapua Welcome to Britain ^_^

[Huapua]

@geeupson Do you not have heating in Britain or do you just lack the ability to feel?

[geeupson]

@Huapua I think it's the ability to feel :) im sat with my windows open at about 9C in a sleevless top and shorts :') something you just get used to

[metalalien79]

You guys should do a video on the fuel/sand nuclear lava inside the Chernobyl basement. Don't go there of course, just talk about it. :)

[rjhrjh3]

If the water was -16C would the water freeze or is Ammonia Nitrate an anti freeze?

[spotlightman1234]

@rjhrjh3 The ammonium nitrate lowers the freezing point of the water a lot like how table salt does.

[DarthGivesAdvice]

If you want an example of an exothermic reaction, I have one word for you. Alderaan.

[BuickDoc]

Have you thought of heating your lab?

[cr0ss0ut]

I need some videos which will help me as an upperclassmen.. :P

[Zee96969696]

so if i add more sugar to my hot coffee and more crystal coffee, then that should make it stronger, sweeter and colder, perhaps even cold, sweet and strong enough to drink

[ILiveForScience]

I don't understand something: if the reaction is taking in heat to sustain itself, why is the reaction mixture getting colder and not hotter? Thank you : )

[YnotDude]

@ILiveForScience

It's sucking heat from it's surroundings, so if you were to feel it with your hand it would suck the heat from your hand and feel cold to the touch. If you think about the opposite reaction: exothermic, then in that case whatever you would touch would be expelling heat so it would feel hot to the touch.

[ILiveForScience]

@YnotDude So the reaction mixture itself is becoming hotter, but because whatever touches is is having energy removed from it, it appears to be cold when observed?

[njimko23]

@ILiveForScience - The heat energy from the surrounding material is being absorbed and converted into other forms of energy. You can't feel those other forms of energy, just like you can't feel the energy of a large block that has been lifted high up. In the case of breaking a chemical bond, you are moving two atoms away from each other, and that often absorbs energy.

[opaldragon75]

14c in the lab!!! time to start protesting for new heater!

My suggestion is to do it with a thermite type reaction; mostly cause it use its own oxygen and leaves a lump of molten metal to keep the heat flowing! That will piss off the administration yet be peaceful and justifiable!

-

ps if you know away to control a thermite reaction to make it last longer let us know cause I would be very interested in that!

[brenoakiy]

so basically, a reaction is endothermic when final products have a weaker bond than initial reagents?

[spotlightman1234]

holy hell that's a lot of ammonium nitrate!!

[ErtyDaSwe]

@spotlightman1234 Lucky they didn't get any fuel oil into that and a spark. That would have gone bad.

[VanillaShoelace]

Do a video about resonance :)

[iToasterman]

Before i watch the video, ima assume this means it cools down and absorbs heat, not releases! am i right?

[brenoakiy]

@iToasterman yes, if it released heat then it would be exothermic

[iToasterman]

@brenoakiy Yea, i know since i watched the video after :P

[pyrioni]

how does it break the strong force without catalyst?

[rhn94]

AMMONIUM NITRATE?!! GREAT SCOTT!!.. don't blow yourselves up there!

[wuj3kdar0]

Does your screensaver say "Good Chemistry!!" ?

[kittercat]

As far as I'm aware, Farenheight measured 0 degrees Fahrenheit at the freezing point of what was salt water, which can be much different than the freezing point of regular H20. He also apparently got the human body tempurature by testing his wife's armpit and a horse. I feel that's kind of archaic! The only countries that still use the farenheight scale are America, Jamaica, Belize, Liberia and an island called Palau. When can us Americans convert to celsius? :(

[Shoyrou]

@kittercat I think using celsius is much more practical. Not only is it easier to convert to kelvin,it has the same temperature variation value as this one, and also sets the freezing point of water at 0ºC and the boiling point at 100ºC (Sea-level pressure), probably making it more easy to learn and compare

[puncheex]

@Shoyrou: I can't imagine the good professor was actually proposing the use of the Fahrenheit scale; he was merely speaking of the history. Who in their right mind would use such a scale? :)

[Shoyrou]

@puncheex Yes, he was only talking about history. A very interesting fact nonetheless.

And as we both know many people use that scale. If they are or not in their right minds, that I do not know hahaha =D

[rageagainstthebath]

That seems to be correct! -16.4 degrees Celsius is 2.48 degrees Fahrenheit, which is close enough to zero. :)

[punishedexistence]

Hmm, wonder if the glacial acetic acid has frozen? It has happened in my lab once, they get awfully cold in winter and dreadfully hot in summer. Nice presentations on the endothermic process...Also in Southpark, Mr Garrison attempts to describe the process once...I say no more.

Great video though!

Thanks.

[Skandalos]

Thats my fav chemist. Can she cook, too?

[rageagainstthebath]

@Skandalos In one movie she made a chemical pie. Go ahead and see it! :)

[andythewooferguy]

I am learning the Haper process at school

[mathiaspaul1987]

2:04, little mistake here:

Formation of ammonia in the Haber Bosch process is an exothermic one.

3/2 H2 + 1/2 N2 -> NH3 Delta HB = -46 kJ/mol

The reason for it being heated to 550 °C in the process is because it woud take very very long to get to the the equilibrium at lower temperatures (Additionally the catalyst works best here). The other thing they use to get the equilibrium to the side of ammonia is high pressure. Thats because literally 4 molecules become 2.

[TheSpankymonkey]

I am starting to wonder whether these experiments are all in order to keep Neil's temperature down, stop him reacting to students. hehe.

[jacoman1234567]

Awesome vid. Btw, professor Poliakoff, I hope to see you on the 3rd of march in Utrecht @ my uni for the pac symposium! Looking forward to seeing and hearing your lecture in person very much!

[Digephil]

is cooking food an endothermic process?

[ManganistanDraselny]

@Digephil yes it is. Because you must add the lot of heat to start water boiling.

[HarithBK]

hmm so could i use this to cool my drinks faster than salt water with ice in it?

[Infloresence]

@HarithBK yup sure can, make sure your drink container is sealed, because ammonium nitrate solution tastes disgusting....

[colourmegone]

I think they used this very same reaction in the 19th century in a device to make home-made ice cream!

[ThePeaceableKingdom]

@colourmegone 19th century device?! I'm way behind the times...

[necevans]

As a chemistry teacher I thought this was looking good but then you said the Haber process is an endothermic reaction whereas it is exothermic and delta H is -92.4 kJ/mol.

Sorry to be picky. Other wise your videos are great.

[periodicvideos]

@necevans I'm not a chemist, but my understanding is that the Haber Process has endo and exo aspects...I think The Prof was really thinking about that initial endothermic part to get the nitrogen out of the air (which is why says "take nitrogen from the air")... but you are quite right about the overall process and we perhaps needed to expand on that... You are clearly an excellent chemistry teacher! ;)

And to think I wanted to keep these definition videos nice and short!

[necevans]

@periodicvideos Ok. But he says it is a very good example of an endothermic reaction but getting nitrogen from the air is a physical process and is also exothermic as you need to remove the heat energy from it in order to turn it into a liquid. The prof says "you have to put in more heat than you get from the formation of the chemical bonds". Once again sorry to be picky but in no way can this be seen to be correct. In teaching the Haber process the fact it is exothermic is an essential point.

[periodicvideos]

@necevans I feel your passion, but posting the same comment four times doesn't make you MORE right! Please stop! :)

[necevans]

@periodicvideos Sorry. Technical glitch! :)

[periodicvideos]

@necevans Mistakes happen! ;)

[Bimm3rcc]

@periodicvideos Wow, what an annoying reply... why dont you just admit your mistakes perioddic videos..

[periodicvideos]

@Bimm3rcc I think we have a good record admitting our mistakes... we make enough of them!!!

I think the tone of the exchange with @necevans was good banter and there were plenty of smiley faces... The context of the same comment being accidentally posted repeatedly was lost when I deleted the extras.

Oh, and there's only one "d" in periodic! :)

[Bimm3rcc]

@periodicvideos :)

[G3org3Master]

@periodicvideos It's a good idea not to get into arguments with youtubers.

[dvrne]

@periodicvideos None of his comments (or the content of his channel!) should have given you the idea that he did this on purpose. Try to be a little more tactful next time, instead of assuming that anyone who posts the same comment multiple times, should be automatically qualified as an asshole.

Thanks

[litres100]

@necevans Yes. the key feature of the harber process is that it is a exothermic reaction that is actually ran at high temperature for the sake of a high reaction rate.

[nicoheckens1]

@periodicvideos I have a simple question you could ask the professor: How do you become a chemist?

[xenomancer40k]

@periodicvideos The Haber Process is indeed endothermic at the conditions given by its design. You may also be thinking of the Ostwald Process (burning ammonia w/ oxygen to make nitric acid) that was joined with the Haber Process in world war 2 (allowing Germany to last much longer in the war) which is very exothermic. The end of the coupled process was combining the two end products to form ammonium nitrate, a cheap but effective explosive, the solvation of which is clearly endothermic.

[chris536343]

@periodicvideos This is actually a little confusing. I always thought the net reaction for the Haber process was exothermic. I agree that some stages of the reaction may be endothermic, but I'm pretty sure the professor was referring to the process in general. I'm not sure why the professor would choose to talk about one specific step of the reaction; not really a "very good example of an endothermic reaction", (I can think of many better examples). That's how it came across anyway!

[MrTollemischief]

@necevans Its reversible so technically you are both right

[necevans]

@MrTollemischief But the prof specifically says making ammonia is an endothermic process so he is talking about it proceeding in one direction only - the exothermic direction.

[SoundsFromTheKitchen]

Loving these definition videos. Really useful.

[Infloresence]

when I'm making up fertilizer solutions I had noticed that depending on how much Ammonium Nitrate I used, a lot of condensation formed on the outside of the container even when it's 35ºC in the shade

[periodicvideos]

@Xerotaerg This was filmed in Neil's lab... we need to keep him as cold as possible!

[nirvana9610]

@periodicvideos Target 0K? :))

[gulllars]

@periodicvideos so it's not that Neil's lab is ~15C because he is so cool? :P

[BIGGGY305]

@periodicvideos loool

[oBLACKIECHANoo]

kind of a pointless video, everyone will know this (unless they are retarded) learned this in year 8.

[periodicvideos]

@oBLACKIECHANoo excellent and insightful comment... I wonder if any young people watch these videos who have not yet completed year 8?

[skippy13312000]

@periodicvideos That is the definition of a troll...

I mean look at the name, BLACKIECHAN??? People need to grow up.

[shintsu01]

@oBLACKIECHANoo that is when you had the education since i dint had the education i learned something.

[IWishIwasAScreamer]

@oBLACKIECHANoo Kinda arogant dont you think? im studying A level chemistry and endothermic/excothermic are the basis for enthalpy change, and so i found this video quite helpfull still. theres no need to make a comment like this. it just makes you seem like an ass

[YashinNashi]

@oBLACKIECHANoo

Yes. How dare they make videos about things we already know. I can't believe this series isn't custom made to MY level of understanding. Don't they realize I already know most of these definitions? What the hell is wrong with them?

[oBLACKIECHANoo]

@YashinNashi hahaha, funy sarcastic comment. anyone with a brain cell should know this.

[ericfam01]

@oBLACKIECHANoo Im in grade eight and I extreamly enjoy all of their videos, even if I do already know the teh information ;D

[otleybey]

This sort of chemistry is useful for synthetic chemists - sometimes you want to chill a reaction mixture using an ice bath, but normal water ice is not cold enough. You can mix a salt with the ice to make a colder ice bath - for instance NaCl or KCl. For even colder temperatures you can use other sorts of ice bath - dry ice (solid carbon dioxide) and acetone gives you -78 celsius.

[ThePeaceableKingdom]

@otleybey Is that why we had to add rock salt to the ice when hand cranking the ice cream maker?

[drinksupreme]

why is it so cold in the lab?

[HRage]

Is there a quick way for me to chill my vodka martini without buying a jar of ammonium nitrate?

[napiton]

14. 6 Celcius?

The reactions in that lab will go slowly :D

[Sep3lio]

14.6 degrees eh? You know its a cold day in the lab when your DMSO freezes!

[jnthnbush]

Just the other day, I was wondering why or how Fahrenheitset zero, thanks for answering it.

[zARCADEz]

what about Startothermic ;)

[zARCADEz]

what about frontothemic ;)

[Harshfate]

shes so beautiful i now wish to be a chemist

[reeceyboy111]

We're studying the Haber Process in Chemistry. :D

[Snazzydog333]

@reeceyboy111 Very important and fairly interesting topic. If you want good advice, remember all the necessary components for the process. I.E Pressure needed, Temperature etc. They ALWAYS ask it in exams

[edheldude]

The Professor needs a new screen saver.

[FallenHero117]

They should do a video on solid-solid reactions, for example barium hydroxide and ammonium chloride, which also happens to be very endothermic.

[leungclj]

next video, exothermic?

[yellowmetalcyborg]

@leungclj Thermite FTW!

[TehConqueror]

@leungclj

no they switch it up, entropy

[macnutz]

So biologists and chemists aren't using endothermic/exothermic in the same way.

[KilgothMirna]

@macnutz In that case biologists are wrong!

[macnutz]

@KilgothMirna No. They use it differently. In biology an endothermic animal (mammals and birds) creates and controls its own body heat. Exothermic animals absorb heat from the sunlight and or environment. I.E.,Reptiles and fish.

[919664]

this cooled me down.

[hockeyboy1094]

4th

[Danthaman1971]

Cool!...

[ArnarNjall]

hello

[mojololo11]

This made my day better :)