Energia química

A combustão na cabeça de um palito de fósforo é um exemplo de liberação da energia química contida nas ligações intramoleculares da substância.

Energia química é um tipo de energia potencial armazenada nas ligações químicas entre os átomos da matéria, sendo liberada a partir da quebra dessas ligações.[1] Sua liberação é percebida, por exemplo, numa combustão.

Exemplos

  • A energia potencial química (dos alimentos) é quando nós comemos e não usamos a energia, ou seja, ela está armazenada (não está em uso). A energia química (dos alimentos) é a energia que está em uso, sendo uma parte transformada e a outra sendo liberada para a natureza em forma de calor.
  • A variação de energia em reações químicas sendo endoenergéticas e exoenergéticas ou seja vindo de dentro ou de fora (respectivamente, absorvem ou liberam energia) está relacionada com a ruptura e formação destas ligações químicas entre os átomos das moléculas.

Análise termoquímica

Ver artigo principal: Termoquímica

Tome-se o caso da combustão de hidrogênio com oxigênio. Pelos devidos cálculos, pode-se concluir que esta reação liberta 235 kJ por mol de água formada. Rever os procedimentos abaixo.

kJ mol−1 ( mil Joule por cada mol de partículas/átomos/moléculas - neste caso falamos em mol de molécula

A ruptura da ligação simples de uma molécula de hidrogênio (H-H em H2) consome 436 kJ mol−1.


H-H E= 436 kJ mol−1


A ruptura da ligação dupla de uma molécula de oxigênio (O=O em O2) consome 499 kJ mol−1.


O=O E= 499 kJ mol−1


A formação das duas ligações simples numa molécula de água (H-O em H2O) liberta 2*460 kJ mol−1.


H-O E= 460 kJ mol−1

(a energia de dissociação de HO-H e H-O é diferente, pelo que este valor é a média de ambos)


Tomando a equação química com as devidas estequiometrias:


H2 + 1/2 O2 → H2O

Pode-se concluir (subtraindo a energia libertada e somando a energia consumida ou absorvida) que a variação energética é:

( 436 +499/2 -2*460 ) kJ mol−1 =

= - 235 kJ mol−1

ou seja, o sistema liberta 235 kJ por cada mol de água formada.

Ver também

Referências

  1. ↑ «Significado da Energia química». Significados. 07 de outubro de 2016. Consultado em 1 de outubro de 2018 
Ícone de esboço Este artigo sobre Química é um esboço. Você pode ajudar a Wikipédia expandindo-o.

Read other articles:

Jeanne Shaheen

American politician (born 1947) Jeanne ShaheenOfficial portrait, 2021United States Senatorfrom New HampshireIncumbentAssumed office January 3, 2009Serving with Maggie HassanPreceded byJohn SununuChair of the Senate Small Business CommitteeIncumbentAssumed office September 27, 2023Preceded byBen CardinRanking Member of the Senate Small Business CommitteeIn officeApril 2, 2015 – February 6, 2018Preceded byBen CardinSucceeded byBen Cardin78th Governor of New HampshireI...

 

 

Telescoping (rail cars)

Type of railway accident This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Telescoping rail cars – news · newspapers · books · scholar · JSTOR (April 2010) (Learn how and when to remove this template message) Cars of the Washington Metro were telescoped in this November 3, 2004 accident at Woodley Park st...

 

 

César Marcano

Venezuelan cyclist For the Venezuelan footballer, see César Marcano (footballer). In this Spanish name, the first or paternal surname is Marcano and the second or maternal family name is Sánchez. César MarcanoPersonal informationFull nameCésar Mervin Marcano SánchezBornOctober 22, 1987 (1987-10-22) (age 36)Carabobo, Venezuela Medal record Men's track cycling Representing  Venezuela Pan American Games 2011 Guadalajara Team sprint 2007 Rio de Janeiro Team Sprint...

Nazionale Under-16 di calcio della Norvegia

Questa voce sull'argomento Nazionali di calcio è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Voce principale: Nazionale di calcio della Norvegia. Norvegia Uniformi di gara Casa Trasferta Sport Calcio Federazione NFFNorges Fotballforbund Codice FIFA NOR Selezionatore Jan Peder Jalland Record presenze - Capocannoniere - Esordio internazionale Danimarca Under-16 6 - 1 Norvegia Under-16 Vanløse, Danimarca; 25 settembre 1971 Migliore vittoria San Ma...

 

 

Appeal procedure before the European Patent Office

Overview about the appeal procedure before the European Patent Office The European Patent Convention (EPC), the multilateral treaty instituting the legal system according to which European patents are granted, contains provisions allowing a party to appeal a decision issued by a first instance department of the European Patent Office (EPO). For instance, a decision of an Examining Division refusing to grant a European patent application may be appealed by the applicant. The appeal procedure b...

 

 

WHLK

Adult hits radio station in Cleveland, Ohio WHLKCleveland, OhioUnited StatesBroadcast areaGreater ClevelandNortheast OhioFrequency106.5 MHz (HD Radio)Branding106.5 The LakeProgrammingLanguage(s)EnglishFormatAdult hitsSubchannelsHD2: Pride RadioOwnershipOwneriHeartMedia(iHM Licenses, LLC)Sister stationsWAKS (HD2)WARFWGAR-FMWMJIWMMS (HD2)WTAMHistoryFirst air dateMay 4, 1960(63 years ago) (1960-05-04)Former call signsWABQ-FM (1960–1961)WXEN (1961–1977)WZZP (1977–1984)WLTF (1984�...

Sotiris Ninis

Sotiris Ninis Informasi pribadiNama lengkap Sotiris NinisTanggal lahir 3 April 1990 (umur 34)Tempat lahir Himara, AlbaniaTinggi 1,73 m (5 ft 8 in)Posisi bermain GelandangInformasi klubKlub saat ini PanathinaikosNomor 29Karier junior2000–2001 Giannis Pathiakakis Academies2001–2003 Apollon Smyrnis2003–2006 PanathinaikosKarier senior*Tahun Tim Tampil (Gol)2006–2012 Panathinaikos 100 (11)2012–2014 Parma 14 (0)2013–2014 → PAOK (pinjaman) 12 (0)2014– Panathinaik...

 

 

China at the 1988 Summer Olympics

Sporting event delegationChina at the1988 Summer OlympicsIOC codeCHNNOCChinese Olympic CommitteeWebsitewww.olympic.cn (in Chinese and English)in Seoul, South Korea17 September–2 October 1988Competitors273 (149 men and 124 women) in 25 sportsFlag bearer Song TaoMedalsRanked 11th Gold 5 Silver 11 Bronze 12 Total 28 Summer Olympics appearances (overview)19521956–198019841988199219962000200420082012201620202024Other related appearances Republic of China (1924–1948) The People...

 

 

莱奥波尔多·加尔铁里

此條目没有列出任何参考或来源。 (2013年2月8日)維基百科所有的內容都應該可供查證。请协助補充可靠来源以改善这篇条目。无法查证的內容可能會因為異議提出而被移除。 莱奥波尔多·加尔铁里Leopoldo Fortunato Galtieri Castelli 阿根廷总统（實質）任期1981年12月22日—1982年6月18日副总统Víctor Martínez前任卡洛斯·拉科斯特继任阿尔弗雷多·奥斯卡·圣琼 个人资料出生(1926-07-15)1926�...

Новая Юность

Новая Юность Сокращённое название(ISO 4) «НЮ» Специализация литературно-художественный журнал Периодичность 6 раз в год Язык русский Главный редактор Ирина Хургина Страна  Россия Дата основания 1992 Объём 80 полос ISSN печатной версии 0869-7361 Веб-сайт new-youth.ru.  Медиафайлы на ...

 

 

1934 in film

Overview of the events of 1934 in film Overview of the events of 1934 in film List of years in film … 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 … In television 1931 1932 1933 1934 1935 1936 1937 In radio 1931 1932 1933 1934 1935 1936 1937 In music 1931 1932 1933 1934 1935 1936 1937 Art Archaeology Architecture Literature Music Philosophy Science +... Years in film 19th century 1870s 1880s 1880 1881 1882 1883 1884 1885 1886 188...

 

 

Lizton, Indiana

Town in Indiana, United StatesTown of Lizton, IndianaTownDowntown LiztonNickname: The only Lizton in the worldLocation of Lizton in Hendricks County, Indiana.Coordinates: 39°52′45″N 86°32′25″W / 39.87917°N 86.54028°W / 39.87917; -86.54028CountryUnited StatesStateIndianaCountyHendricksTownshipUnionEstablished1851Area[1] • Total0.66 sq mi (1.72 km2) • Land0.66 sq mi (1.72 km2) • W...

Buckinghamshire Council

Local authority of Buckinghamshire, England Buckinghamshire CouncilCouncil logoTypeTypeUnitary authority HistoryFounded1 April 2020[a]Preceded byBuckinghamshire County CouncilLeadershipChairMimi Harker, Conservative since 15 May 2024[1] LeaderMartin Tett, Conservative since 1 April 2020 Chief ExecutiveRachael Shimmin since July 2019[2] StructureSeats147Political groups Administration (111)   Conservative (111) Alliance Grouping (20)   Liberal Dem...

 

 

1974 Safari Rally

1974 Safari Rally22nd East African Safari RallyRound 2 of the 1974 World Rally Championship season← Previous eventNext event →Host country KenyaRally baseNairobi, KenyaDates run11 April – 15 April 1974Stage surfaceGravelOverall distance5,000 km (3,100 miles)(approx.)StatisticsCrews99 at start, 16 at finishOverall resultsOverall winner Joginder Singh David Doig Mitsubishi Motors The 1974 Safari Rally (formally the 22nd East African Safari Rally) was the ...

 

 

Wired glove

Input device for human–computer interaction A woman using a head-mounted display and wired gloves A wired glove (also called a dataglove[1][2] or cyberglove) is an input device for human–computer interaction worn like a glove. Various sensor technologies are used to capture physical data such as bending of fingers. Often a motion tracker, such as a magnetic tracking device or inertial tracking device, is attached to capture the global position/rotation data of the glove. T...

Robonaut

Humanoid robot Two Robonaut 2 robots A robonaut is a humanoid robot, part of a development project conducted by the Dexterous Robotics Laboratory at NASA's Lyndon B. Johnson Space Center (JSC) in Houston, Texas. Robonaut differs from other current space-faring robots in that, while most current space robotic systems (such as robotic arms, cranes and exploration rovers) are designed to move large objects, Robonaut's tasks require more dexterity. The core idea behind the Robonaut series is to h...

 

 

Piazza della Repubblica (Milano)

Piazza della RepubblicaVista panoramicaNomi precedentiPiazzale Stazione CentralePiazzale Fiume LocalizzazioneStato Italia CittàMilano Informazioni generaliTipopiazza Superficie73 500 m² IntitolazioneReferendum istituzionale del 2 giugno 1946 Costruzione1865 CollegamentiIntersezioniVia Vittor Pisani, Viale Tunisia, Via Camillo Finocchiaro Aprile, Via Panfilo Castaldi, Viale Vittorio Veneto,[Viale Città di Fiume, Via Iginio Ugo Tarchetti, Via Filippo Turati, Via Giuseppe Parini, Vi...

 

 

Charles Martel

Frankish military and political leader (c. 688–741) This article is about the Frankish ruler. For other uses, see Charles Martel (disambiguation). Charles Martel Duke and Prince of the Franks Mayor of the Palace 1839 sculpture of Charles by Jean Baptiste Joseph De Bay père, located in the Palace of Versailles[1]Duke and Prince of the FranksReign718 – 22 October 741PredecessorPepin of HerstalSuccessor Carloman Pepin the Short Mayor of the Palace of AustrasiaReign715 – 22 October...

Mutsu Province

Michinoku redirects here. For the sumo coach known as Michinoku Oyakata, see Kirishima Kazuhiro. Mutsu Province陸奥国Province of Japan654–1869Map of Japanese provinces (1868) with Mutsu Province highlightedCapitalMiyagi DistrictHistory • Established 654• Disestablished 1869 Succeeded by Rikuō Province Rikuchū Province Rikuzen Province Iwashiro Province Iwaki Province Today part ofFukushima PrefectureMiyagi PrefectureIwate PrefectureAkita PrefectureAomori Prefecture F...

 

 

Paracanthocobitis

Genus of fishes Paracanthocobitis Acanthocobitis (Paracanthocobitis) zonalternans Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Cypriniformes Family: Nemacheilidae Genus: Acanthocobitis Subgenus: ParacanthocobitisS. Grant, 2007 Paracanthocobitis is a genus, or subgenus, of freshwater fish in the family Nemacheilidae. This genus is known from the Indus basin in Pakistan to the Mekong basin of Cambodia and Laos The type species is Pa...