How to Draw Born Haber Cycle of Ionic Compounds - Energetics
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- เผยแพร่เมื่อ 8 ก.ค. 2018
- In this video we want to learn how to draw the Born Haber Cycle of ionic compounds using CaCl2 as an example.
We usually use the energy level diagram to present the Born Haber Cycle, which can be broken down into 4 steps.
1. Formation
Formation involves the reaction from elements in the standard state to ionic compound. Usually enthalpy change of formation for ionic compounds is exothermic as ionic compounds are stable.
We can draw this close to the bottom of the energy level diagram as the rest of the terms would be endothermic hence pointing upwards.
2. Atomisation
Atomisation involves forming gaseous atoms for both calcium metal and chlorine gas. Both terms are endothermic as energy is required to break all bonds in the elements to form gaseous atoms.
For Ca we will be given the enthalpy change of atomisation of metal.
For Cl2 usually we use bond energy of Cl-Cl bond which can be found in the Data Booklet.
3. Ionisation
Ionisation involves removing the electrons from Ca (ionisation energy) and adding electrons to Cl (electron affinity).
Removing 2 electrons from Ca to form Ca2+ will be the first and second ionisation energies of Ca which can be found in the Data Booklet. Ionisation energy is endothermic as energy is required to overcome attraction between nucleus and valence electron.
Adding electron to Cl to form Cl- will be the first electron affinity of Cl. First electron affinity is exothermic as energy is released from attraction formed between nucleus and added electron.
4. Lattice Energy
The last step involves lattice energy which is the forming of ionic compound from its constituent gaseous ions.
Since strong ionic bonds are formed, lattice energy is highly exothermic.
Hess' Law
We can use the follow expression to work out the relationship of all the terms in the Born Haber cycle. This expression is valid for all ionic compounds.
For the detailed step-by-step discussion on how to draw the Born Haber Cycle, check out this video!
Topic: Energetics, Physical Chemistry, A Level Chemistry, Singapore
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omg i finally understand born haber cycle!! thankyou so much!!
Hi Janelle! Glad you found the video useful! :)
Couldn’t wrap this around my head until just now, thankyou so much!
Thank you so much! I finally understand the Born Haber cycle after searching endlessly on youtube haha
thanks a lot! you're the greatest teacher for chemistry
Thank you so much!! This video made so much more sense than the teacher and the textbook did!
These videos help a lot specially in this period of quarantine ...thank you so much ...big thumbs up all the way from Sri lanka..
Hi Hilary thank you so much! Stay safe and healthy during this quarantine! :)
splendid, concise great demonstration. Thank you!
It's a very clear explanation and illustration as well. Good work.
You deserve a lot more viewers and subscribers. Your explanations are so clear and concise. Thanks
Thank you for your kind compliments! Really appreciate it :)
@@ChemistryGuru You are welcome. You deserve high praise.
You life saviour thank you so much
Thank you for this video! Helped me a lot ^^
Thank you so much for this.
You're a great teacher.
Thank you so much, this was so helpful!
You're good sir, precise yet elaborate
Thank you so much 🤝
Thank this was very helpful ❤😊😊😊
Thank you
At last clear the topics
Thank you so much, Sir!
Thank you very much for this.
Thank you Cher!!🥲
Hats off for this Sir
This awesome muri chiba chibe chibabest when it comes to chemistry
Thank u so much sir...was so lost b4
true lifesaver!
That was amazing
very helpful! :D
Thank you so much sir
hello sir. i want to ask. what about Ca3N2? it is the draw was same? so Ca3 was solid and there is 3 Ca. are we going to separate the Ca? so Ca3 going to 3Ca (atomic)? if like that, i think we need to build one more line. what i mean is like you did Cl2, you make it to 2Cl (two atoms). and my case here is Ca3, i want to make them three atoms Ca. what you say sir?
thank you very much before for you're attention
i thought that the 2nd electron affinity would be above the first AE at the extreme top du do it being endothermic.
Why do we put 2 in front of the Chlorine?
Thanka
Could we also say that the Ca(s) is being dissociated into Ca (g), like so its not atomisation energy being used but dissociation energy?
dissociation energy is involving breaking of 1 mole of covalent bonds, so for metals there is no dissociation energy since the attractions holding calcium atoms together are metallic bonds and not covalent bonds.
atomisation is to convert elements to 1 mole of gaseous atoms, so the bonds broken depends on the attraction in the elements, eg for metals will be metallic bonds, simple and giant molecules will be covalent bonds.
@@ChemistryGuru Thank you so much!
@@ChemistryGuru Hello, I have one other question. Could we consider sublimation energy and atomisation energy to be the same thing?
@@roriefriz9068 sublimation is a physical process from solid to gas so it's different from atomisation. In general if the names of the processes are different then they must mean different things, if not there is no need to have 2 processes with different names but are the exact same process.
Wow. But I need a tution
Can we use an energy cycle diagram to represent the born haber cycle?
by right both energy cycle and energy level diagram can represent Born Haber cycle (or any question involving Hess' Law), but for A Level syllabus almost all schools are using energy level diagram in their marking scheme.
So it is recommended to stick with energy level diagram for Born Haber Cycle.
God loves you all
Whats the difference between dissociation energy and atomisation energy?
bond dissociation energy is energy required to break 1 mole of covalent bond. atomisation energy is energy required to convert elements to 1 mole of gaseous atoms. They are different processes.
@@ChemistryGuru Could we say that Cl2(g) is using dissociation energy to be broken up into isolated atoms, instead of atomisation energy? In the above you said it was (ΔH at of Cl*2), wondering if we could say its the same as (ΔHs)? Thanks again:)) I really love your channel, its helping me so much!!!
@@roriefriz9068 yes in the case of Cl2(g) = 2Cl(g), we can describe this as either 2 x atomisation of Cl(g) or Bond dissociation energy of Cl-Cl. Both describe the same process.
Why didn't you use the enthalpy of sublimation to change the state of calcium from solid to gaseous?
the process of Ca(s) to Ca(g) is considered at atomisation instead of sublimation
Why is it always exothermic? (Ionic reaction)
Because the bond made are greater than the bonds broken within the chemical reaction, therefore, due to energy being released when bonds are formed, it is a negative ( exothermic) enthalpy change. It is a much stronger bond in ionic NaCl than it is in gaseous Na^+ + Cl^-. Hope this helps!!
What is endodermic and exodermic😂😂
endothermic process absorbs heat from the surrounding so the temperature of surrounding will decrease. exothermic process releases heat to the surrounding so temperature of the surrounding will increase.
keep doin this good work man, shout out to yo bro...all the way up from East Africa in Tanzanian
Thanks Kendrick for the encouragement! Yup will keep working on this! 😁
thank you
Thanks It helps a lot.
Hi Rajpura thanks! Glad the video was useful 😄
great ,nice video
thanks for the compliment!
Hello! May I ask if the sequence to draw any born-haber cycle is fixed?
Hi Rachel actually the sequence need not be fixed. But since Born Haber cycle is a fixed cycle with basically the same processes so it's easier to draw it in a standardised way. Much easier to remember in this way