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
As has been pointed out, the Haber process is Exothermic to the tune of negative 92kJ (for the balanced equation N2 + 3H2 --> 2NH3). This is not a good example of an endothermic change. This is quite an important error as the Haber process forms part of most A level and IB syllabus requirements in the equilibrium section. The very fact that it is exothermic is used to discuss the intermediate temperature used (450ºC) which is a balance between the need to attain equilibrium rapidly and the position of equilibrium (15-20% ammonia). Increasing the temperature decreases the proportion of ammonia at equilibrium due to the fact that it is exothermic. The clever twist applied by Haber was to recycle the unreacted gases back into the reaction vessel after removing the ammonia by liquefaction.
@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
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
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!
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
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.
@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.
@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.
@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.
@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).
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!
@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. :)
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.
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 ?
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??
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? :(
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.
@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
@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
Why she had used too much of Ammonium nitrate for simple demonstration? Few grams were enough. Please do not waste chemicals unnecessarily albeit some are cheap like Ammonium nitrate.
@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.
the screensaver is moving across the screens behind :D
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
As has been pointed out, the Haber process is Exothermic to the tune of negative 92kJ (for the balanced equation N2 + 3H2 --> 2NH3). This is not a good example of an endothermic change.
This is quite an important error as the Haber process forms part of most A level and IB syllabus requirements in the equilibrium section. The very fact that it is exothermic is used to discuss the intermediate temperature used (450ºC) which is a balance between the need to attain equilibrium rapidly and the position of equilibrium (15-20% ammonia). Increasing the temperature decreases the proportion of ammonia at equilibrium due to the fact that it is exothermic. The clever twist applied by Haber was to recycle the unreacted gases back into the reaction vessel after removing the ammonia by liquefaction.
@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
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
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. ;-)
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!
Mixing Barium hydroxide with Ammonium nitrate would be a very good example for Endothermic reaction.
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
@periodicvideos I have a simple question you could ask the professor: How do you become a chemist?
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.
@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.
~15 Celsius seems cold for a room
@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.
@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.
@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).
why is it so cold in your lab? Our lab is usually around 21C year round.
That seems to be correct! -16.4 degrees Celsius is 2.48 degrees Fahrenheit, which is close enough to zero. :)
@Jisse000 it's Pyrex, which is thermally stable glass
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!
@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. :)
@Digephil yes it is. Because you must add the lot of heat to start water boiling.
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.
@otleybey Is that why we had to add rock salt to the ice when hand cranking the ice cream maker?
They should do a video on solid-solid reactions, for example barium hydroxide and ammonium chloride, which also happens to be very endothermic.
Can you show the experiment that Fahrenheit did to get his lowest temperature?
@Eltron25 because the atoms move slower and so they dont bump into each other often therefore making the reaction slow.
So did the water you were using freeze? i would think that would make the reaction difficult?
So is this how they make those little chocolate cups that go cold when you eat them?
if you were to agitate the solution, would it become colder still?
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 ?
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?
you guys should do a poll! who is your favorite scientist! :)
so basically, a reaction is endothermic when final products have a weaker bond than initial reagents?
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??
how does it break the strong force without catalyst?
This made my day better :)
Loving these definition videos. Really useful.
@rjhrjh3 The ammonium nitrate lowers the freezing point of the water a lot like how table salt does.
Just the other day, I was wondering why or how Fahrenheitset zero, thanks for answering it.
I learnt about this recently in chemistry yr 11. Exothermic is the opposite, gives out heat or explosion!
@periodicvideos
No, I haven't. How do I find it?
@HarithBK yup sure can, make sure your drink container is sealed, because ammonium nitrate solution tastes disgusting....
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? :(
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.
why is it so cold in the lab?
@periodicvideos so it's not that Neil's lab is ~15C because he is so cool? :P
@iToasterman yes, if it released heat then it would be exothermic
@geeupson Do you not have heating in Britain or do you just lack the ability to feel?
@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
@leungclj
no they switch it up, entropy
Ahh, I finally understand why 0°F isn't completely arbitrary now... I still like °C though...
@Skandalos In one movie she made a chemical pie. Go ahead and see it! :)
I am learning the Haper process at school
I need some videos which will help me as an upperclassmen.. :P
I think they used this very same reaction in the 19th century in a device to make home-made ice cream!
what about Startothermic ;)
@colourmegone 19th century device?! I'm way behind the times...
what about frontothemic ;)
@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
A thermistor with a whet-stone bridge circuit would have been more accurate than the thermocouple.
Why she had used too much of Ammonium nitrate for simple demonstration? Few grams were enough. Please do not waste chemicals unnecessarily albeit some are cheap like Ammonium nitrate.
We're studying the Haber Process in Chemistry. :D
@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.
I am starting to wonder whether these experiments are all in order to keep Neil's temperature down, stop him reacting to students. hehe.
Thats my fav chemist. Can she cook, too?
Now I know where fahrenheit came from :)
Felis catus is your taxonomic nomenclature: an endothermic quadruped, carnivorous by nature.
14.6 degrees eh? You know its a cold day in the lab when your DMSO freezes!
Is there a quick way for me to chill my vodka martini without buying a jar of ammonium nitrate?
@oBLACKIECHANoo Im in grade eight and I extreamly enjoy all of their videos, even if I do already know the teh information ;D
Yeah, they are connected to the same PC.
holy hell that's a lot of ammonium nitrate!!
next video, exothermic?
@periodicvideos Target 0K? :))
@casmatt1 That'd be waaaaay too hard! They're all awesome in their own way. :)
@periodicvideos It's a good idea not to get into arguments with youtubers.
holy crap this is what happens with the baking soda and vinegar back in first grade
AMMONIUM NITRATE?!! GREAT SCOTT!!.. don't blow yourselves up there!
@periodicvideos :)
Your lab is sooooo cold (15*C)!
Cool!...
Its 15 degrees in your lab!?! Heat it up!! You guys must be freezing your socks off!
So much for 'room temperature'...
15C in your lab. Im glad Im not using that lab, would be freezing all the time.
@periodicvideos That is the definition of a troll...
I mean look at the name, BLACKIECHAN??? People need to grow up.
should be at least 20.
@leungclj Thermite FTW!
4th
@periodicvideos loool
show us how to detonate Ammonia Nitrate :D
14. 6 Celcius?
The reactions in that lab will go slowly :D
lol