Gaya van der Waals: Perbedaan antara revisi
Konten dihapus Konten ditambahkan
Tidak ada ringkasan suntingan Tag: Suntingan perangkat seluler Suntingan peramban seluler |
Rescuing 14 sources and tagging 0 as dead.) #IABot (v2.0.9.5 |
||
| (34 revisi perantara oleh 17 pengguna tidak ditampilkan) | |||
Baris 1:
'''Gaya van der Waals''' dalam ilmu [[kimia]] merujuk pada jenis gaya antara [[molekul]].<ref>{{Cite web|title=van der Waals forces {{!}} chemistry and physics {{!}} Britannica|url=https://www.britannica.com/science/van-der-Waals-forces|website=www.britannica.com|language=en|access-date=2022-12-13|archive-date=2023-07-27|archive-url=https://web.archive.org/web/20230727054052/https://www.britannica.com/science/van-der-Waals-forces|dead-url=no}}</ref> Istilah ini pada awalnya merujuk pada jenis gaya antarmolekul, dan hingga saat ini masih digunakan dalam pengertian tersebut, tetapi saat ini lebih umum merujuk pada gaya-gaya yang timbul dari [[polarisasi]] molekul menjadi [[dipol]].
Hal ini mencakup gaya yang timbul dari dipol tetap ([[gaya Keesom]]), dipol rotasi atau bebas ([[gaya Debye]]) serta pergeseran distribusi awan
Gaya ini dikemukakan pertama kali oleh [[Johannes van der Waals]] (1837-1923).<ref>{{Cite web|title=The Nobel Prize in Physics 1910|url=https://www.nobelprize.org/prizes/physics/1910/waals/biographical/|website=NobelPrize.org|language=en-US|access-date=2022-12-13|archive-date=2019-06-04|archive-url=https://web.archive.org/web/20190604025941/https://www.nobelprize.org/prizes/physics/1910/waals/biographical/|dead-url=no}}</ref> Gaya Van der Waals merupakan gaya tarik menarik listrik yang relatif lemah akibat kepolaran molekul yang permanen atau terinduksi.<ref>{{Cite journal|title=Van-der-Waals Attraction|url=http://dx.doi.org/10.1007/springerreference_67891|journal=SpringerReference|location=Berlin/Heidelberg|publisher=Springer-Verlag}}</ref> Kepolaran permanen terjadi akibat kepolaran di dalam molekul, sedangkan kepolaran tidak permanen terjadi akibat molekul terinduksi oleh partikel lain yang bermuatan sehingga molekul bersifat polar sesaat secara spontan.
Nama gaya ini diambil dari nama kimiawan Belanda [[Johannes van der Waals]], yang pertama kali mencatat jenis gaya ini. [[Potensial Lennard-Jones]] sering digunakan sebagai model hampiran untuk gaya van der Waals sebagai fungsi dari waktu. ▼
▲
Konsep gaya tarik menarik antar molekul ini digunakan untuk menurunkan persamaan zat-zat yang berada dalam fase gas. Gaya ini terjadi karena adanya gaya tarik menarik antara inti atom dengan elektron atom lain yang disebut gaya tarik menarik elektrostatis ([[Hukum Coulomb|gaya coulomb]]) yang umumnya terdapat pada senyawa polar. Pada molekul non polar gaya Van Der Waals timbul karena adanya dipol-dipol sesaat atau gaya London.<ref>{{Cite web|last=Vollbrecht|first=Cecilia|date=2021-12-21|title=London Dispersion and Van der Waals Forces|url=https://chemistrytalk.org/london-dispersion-van-der-waals/|website=ChemTalk|language=en-US|access-date=2022-12-13|archive-date=2023-03-22|archive-url=https://web.archive.org/web/20230322232915/https://chemistrytalk.org/london-dispersion-van-der-waals/|dead-url=no}}</ref>
{{chemical bonds}}▼
'''Interaksi van der Waals''' teramati pada gas mulia, yang amat stabil dan cenderung tak berinteraksi. Hal ini menjelaskan sulitnya gas mulia untuk mengembun. Tetapi, makin besar ukuran atom gas mulia (makin banyak elektronnya) makin mudah gas tersebut berubah menjadi cairan.<ref>{{Cite book|date=2019-04-12|url=https://books.google.com/books?id=z2-SDwAAQBAJ&newbks=0&printsec=frontcover&hl=en|title=Encyclopedia of Ocean Sciences|publisher=Academic Press|isbn=978-0-12-813082-7|pages=280|language=en|url-status=live|access-date=2022-12-13|archive-date=2022-12-13|archive-url=https://web.archive.org/web/20221213195922/https://books.google.com/books?id=z2-SDwAAQBAJ&newbks=0&printsec=frontcover&hl=en|dead-url=no}}</ref>
== Jenis ==
Berdasarkan kepolaran partikelnya gaya Van Der Waals dibagi menjad empat macam; Interaksi ion-dipol (molekul polar), Interaksi dipol-dipol, Interaksi ion-dipol terinduksi dan Interaksi dipol-dipol terinduksi.
=== Interaksi ion-dipol ===
Terjadi interaksi/tarik menarik antara ion dengan molekul polar (dipol) yang relatif cukup kuat. Dapat dilihat berdasarkan Mr (massa molekul relatif) semakin besar Mr semakin besar gaya ion dipol. Rumusnya adalah:
<math>Mr = x</math> jumlah total ion molekul
=== Interaksi dipol-dipol (molekul polar) ===
Merupakan interaksi antara sesama molekul polar (dipol) yang terjadi antara ekor dan kepala dari molekul itu sendiri.
=== Interaksi ion-dipol terinduksi ===
Merupakan interaksi ion dengan dipol terinduksi. Dipol terinduksi merupakan molekul netral dan menjadi dipol akibat induksi partikel bermuatan yang berada di dekatnya. Ikatan ini relatif lemah karena kepolaran molekul terinduksi relatif kecil daripada dipol permanen.
=== Interaksi dipol-dipol terinduksi ===
Molekul dipol dapat membuat molekul netral lain yang bersifat dipol terinduksi sehingga terjadi interaksi dipol-dipol terinduksi dan ikatannya relatif lemah sehingga prosesnya berlangsung secara lambat.Antar aksi dipol terinduksi-dipol terinduksi (gaya london)
Gaya Van der Waals bersifat permanen sehingga lebih kuat dari gaya london. Gaya Van Der Waals terdapat pada senyawa Hidrokarbon seperti CH<sub>4</sub>. Perbedaan keelektronegatifan C(2,5) dengan H(2,1) sangat kecil, yaitu 0,4. Senyawa-senyawa yang memiliki ikatan Van Der Waals akan mempunyai titik didih yng sangat rendah, tetapi akan semakin tinggi apabila Mr bertambah karena ikatan akan semakin kuat <chem>(C4H10 > C3H8 > C2 H6> CH4)</chem>
== Karakteristik ==
Ciri-ciri utama gaya van der Waals adalah:<ref>{{Cite web|last=Helmenstine|first=Anne Marie|date=30 November 2019|title=Van der Waals Forces: Properties and Components|url=https://www.thoughtco.com/definition-of-van-der-waals-forces-604681|website=ThoughtCo|language=en|access-date=2022-12-13|archive-date=2023-03-08|archive-url=https://web.archive.org/web/20230308183751/https://www.thoughtco.com/definition-of-van-der-waals-forces-604681|dead-url=no}}</ref><ref>{{Cite book|last=Sethi|first=M. S.|last2=Satake|first2=M.|date=1992|url=https://www.worldcat.org/title/912437861|title=Chemical bonding.|location=New Delhi|publisher=Discovery Publishing House|isbn=9788171411634|url-status=live|access-date=2022-12-13|archive-date=2023-07-09|archive-url=https://web.archive.org/web/20230709195251/https://www.worldcat.org/title/912437861|dead-url=no}}</ref>
* lebih lemah dari ikatan kovalen dan ionik normal.
* Gaya Van der Waals bersifat aditif dan tidak dapat dijenuhkan..
* Merupakan gaya jarak pendek dan oleh sebab itu hanya terjadi pada interaksi antar partikel terdekat (bukan semua partikel). Gaya tarik Van der Waals menjadi lebih besar jika antar molekul semakin mendekat.
* Gaya Van der Waals tidak bergantung pada suhu kecuali untuk interaksi dipol-dipol.
== Referensi ==
<references />
== Bacaan lanjutan ==
* {{cite paper | first1 = Iver | last1 = Brevik | first2 = V. N. | last2 = Marachevsky | first3 = Kimball A. | last3 = Milton | title = Identity of the van der Waals Force and the Casimir Effect and the Irrelevance of these Phenomena to Sonoluminescence|url=https://www.researchgate.net/publication/2085236_Identity_of_the_van_der_Waals_Force_and_the_Casimir_Effect_and_the_Irrelevance_of_These_Phenomena_to_Sonoluminescence | arxiv = hep-th/9901011 | bibcode = 1999hep.th....1011M | year = 1999 }}
* {{cite journal | first1 = I. D. | last1 = Dzyaloshinskii | first2 = E. M. | last2 = Lifshitz | first3 = Lev P. | last3 = Pitaevskii | title = Общая теория ван-дер-ваальсовых сил | url = http://ufn.ru/ufn61/ufn61_3/Russian/r613b.pdf | trans-title = Teori umum gaya van der Waals | journal = Uspekhi Fizicheskikh Nauk | language = ru | volume = 73 | issue = 381 | date = 1961 | access-date = 2020-01-06 | archive-date = 2017-08-09 | archive-url = https://web.archive.org/web/20170809091100/http://ufn.ru/ufn61/ufn61_3/Russian/r613b.pdf | dead-url = no }}
** terjemahan Inggris: {{cite journal | first1 = I. D. | last1 = Dzyaloshinskii | first2 = E. M. | last2 = Lifshitz | first3 = L. P. | last3 = Pitaevskii | title = General theory of van der Waals' forces | journal =[[Soviet Physics Uspekhi]] | volume = 4 | issue = 2 | page = 153 | date = 1961 | doi = 10.1070/PU1961v004n02ABEH003330 | bibcode = 1961SvPhU...4..153D }}
* {{cite book | first1 = L. D. | last1 = Landau | first2 = E. M. | last2 = Lifshitz | title = Electrodynamics of Continuous Media | url = https://archive.org/details/electrodynamicso00land | url-access = registration | publisher = Pergamon | location = Oxford | date = 1960 | pages = [https://archive.org/details/electrodynamicso00land/page/368 368–376] }}
* {{cite book | authorlink = Dieter Langbein | last = Langbein | first = Dieter | title = Theory of van der Waals Attraction | url = https://www.google.co.id/books/edition/Theory_of_Van_der_Waals_Attraction/pJl0DgAAQBAJ?hl=en&gbpv=1 | publisher = Springer-Verlag | location = New York, Heidelberg | date = 1974 | series = Springer Tracts in Modern Physics | volume = 72 | access-date = 2022-12-13 | archive-date = 2023-07-29 | archive-url = https://web.archive.org/web/20230729164743/https://www.google.co.id/books/edition/Theory_of_Van_der_Waals_Attraction/pJl0DgAAQBAJ?hl=en&gbpv=1 | dead-url = no }}
* {{cite web | first = Mark | last = Lefers | url = http://groups.molbiosci.northwestern.edu/holmgren/Glossary/Definitions/Def-V/van_der_Waals_force.html | title = van der Waals dispersion force | publisher = Holmgren Lab | work = Life Science Glossary | access-date = 2020-01-06 | archive-date = 2019-07-24 | archive-url = https://web.archive.org/web/20190724044455/http://groups.molbiosci.northwestern.edu/holmgren/Glossary/Definitions/Def-V/Van_der_Waals_force.html | dead-url = yes }}
* {{cite journal | first = E. M. | last = Lifshitz |title=Russian title is missing | trans-title = The Theory of Molecular Attractive Forces between Solids | journal = Zhurnal Éksperimental'noĭ I Teoreticheskoĭ Fiziki | volume = 29 | issue = 1 | page = 94 | date = 1955 | language = ru }}
** terjemahan Inggris: {{cite journal | first = E. M. | last = Lifshitz | title = The Theory of Molecular Attractive Forces between Solids | url = https://www.mit.edu/~kardar/research/seminars/Casimir/LifshitzTheory.pdf | journal = Soviet Phys. Journal of Experimental and Theoretical Physics | volume = 2 | issue = 1 | page = 73 | date = January 1956 | access-date = 2022-12-13 | archive-date = 2022-12-13 | archive-url = https://web.archive.org/web/20221213200457/https://www.mit.edu/~kardar/research/seminars/Casimir/LifshitzTheory.pdf | dead-url = no }}
* {{cite web | publisher = Western Oregon University | url = http://www.wou.edu/las/physci/ch334/lecture/intermol/london.htm | title = London force animation | work = Intermolecular Forces | access-date = 2020-01-06 | archive-date = 2018-10-18 | archive-url = https://web.archive.org/web/20181018002156/http://www.wou.edu/las/physci/ch334/lecture/intermol/london.htm | dead-url = no }}
* {{cite book | first = J. | last = Lyklema | title = Fundamentals of Interface and Colloid Science | url = https://www.google.co.id/books/edition/Fundamentals_of_Interface_and_Colloid_Sc/roFTFahmLC4C?hl=en&gbpv=1 | page = 4.43 | access-date = 2022-12-13 | archive-date = 2023-07-29 | archive-url = https://web.archive.org/web/20230729164726/https://www.google.co.id/books/edition/Fundamentals_of_Interface_and_Colloid_Sc/roFTFahmLC4C?hl=en&gbpv=1 | dead-url = no }}
* {{cite book | last = Israelachvili | first = Jacob N. | title = Intermolecular and Surface Forces | url = https://www.google.co.id/books/edition/Intermolecular_and_Surface_Forces/MVbWBhubrgIC?hl=en&gbpv=1 | publisher = [[Academic Press]] | date = 1992 | isbn = 9780123751812 | access-date = 2022-12-13 | archive-date = 2023-07-29 | archive-url = https://web.archive.org/web/20230729164743/https://www.google.co.id/books/edition/Intermolecular_and_Surface_Forces/MVbWBhubrgIC?hl=en&gbpv=1 | dead-url = no }}
== Pranala dalam ==
* {{cite web |url=http://antoine.frostburg.edu/chem/senese/101/liquids/faq/h-bonding-vs-london-forces.shtml |title=What are van der Waals forces? |first=Fred |last=Senese |publisher=Frostburg State University |year=1999 |accessdate=1 March 2010 |archive-date=2000-04-25 |archive-url=https://web.archive.org/web/20000425142019/http://antoine.frostburg.edu/chem/senese/101/liquids/faq/h-bonding-vs-london-forces.shtml |dead-url=no }} An introductory description of the van der Waals force (as a sum of attractive components only)
* {{cite web |url=http://www.ted.com/talks/robert_full_learning_from_the_gecko_s_tail?language=en |title=Robert Full: Learning from the gecko's tail |date=1 February 2009 |publisher=[[TED (conference)|TED]] |accessdate=5 October 2016 |archive-date=2023-03-24 |archive-url=https://web.archive.org/web/20230324134155/https://www.ted.com/talks/robert_full_learning_from_the_gecko_s_tail?language=en |dead-url=no }} TED Talk on biomimicry, including applications of van der Waals force.
* {{cite journal |title=The influence of humidity on the attachment ability of the spider ''Philodromus dispar'' (Araneae, Philodromidae) |journal=Proceedings of the Royal Society B: Biological Sciences |volume=279 |issue=1726 |pages=139–143 |date=18 May 2011 |doi=10.1098/rspb.2011.0505 |pmid=21593034 |pmc=3223641 |last1=Wolff |first1=J. O. |last2=Gorb |first2=S. N. }}
{{Authority control}}
| |||