{"id":2084,"date":"2016-03-28T23:00:12","date_gmt":"2016-03-28T23:00:12","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=2084"},"modified":"2024-08-21T17:00:02","modified_gmt":"2024-08-21T17:00:02","slug":"2084-2","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/fisica-termica\/termodinamica\/trabalho-de-um-gas-transformacao-ciclica\/2084-2\/","title":{"rendered":"Trabalho de um g\u00e1s \u2013 Transforma\u00e7\u00e3o c\u00edclica – Resolu\u00e7\u00e3o"},"content":{"rendered":"

Exerc\u00edcios de vestibulares com resolu\u00e7\u00e3o comentada sobre <\/b><\/span><\/span><\/span><\/p>\n

Trabalho de um g\u00e1s \u2013 Transforma\u00e7\u00e3o c\u00edclica<\/b><\/span><\/span><\/span><\/p>\n

01-(UFMS-MS)<\/b><\/span><\/span><\/span> Sem variar sua massa, um g\u00e1s ideal sofre uma transforma\u00e7\u00e3o a volume constante. \u00c9 correto afirmar que<\/b><\/span><\/span><\/p>\n

a) a transforma\u00e7\u00e3o \u00e9 isot\u00e9rmica.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

b) a transforma\u00e7\u00e3o \u00e9 isob\u00e1rica.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

c) o g\u00e1s n\u00e3o realiza trabalho.<\/b><\/span><\/span><\/p>\n

d) sua press\u00e3o diminuir\u00e1,se a temperatura do g\u00e1s aumentar.<\/b><\/span><\/span><\/p>\n

e) a varia\u00e7\u00e3o de temperatura do g\u00e1s ser\u00e1 a mesma em qualquer escala termom\u00e9trica.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

02-(Uneb-BA)<\/b><\/span><\/span><\/span> Um g\u00e1s ideal sofre uma expans\u00e3o isob\u00e1rica, variando seu volume de 2 m<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sup>at\u00e9 5 m<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sup>. Se o trabalho realizado sobre o g\u00e1s foi de 30J, a press\u00e3o mantida durante a expans\u00e3o, em N\/m<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>, foi de:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

03-(PUCCAMP-SP)<\/b><\/span><\/span><\/span> O biodiesel resulta da rea\u00e7\u00e3o qu\u00edmica desencadeada por uma mistura de \u00f3leo vegetal com \u00e1lcool de cana.<\/b><\/span><\/span><\/p>\n

A utiliza\u00e7\u00e3o do biodiesel et\u00edlico como combust\u00edvel no pa\u00eds permitiria uma redu\u00e7\u00e3o sens\u00edvel nas emiss\u00f5es de gases poluentes no ar, bem como uma amplia\u00e7\u00e3o da matriz energ\u00e9tica brasileira.<\/b><\/span><\/span><\/p>\n

O combust\u00edvel testado foi desenvolvido a partir da transforma\u00e7\u00e3o qu\u00edmica do \u00f3leo de soja. \u00c9 tamb\u00e9m chamado de B-30 porque \u00e9 constitu\u00eddo de uma propor\u00e7\u00e3o de 30% de biodiesel e 70% de diesel metropolitano. O primeiro diagn\u00f3stico divulgado considerou performances dos ve\u00edculos quanto ao desempenho, durabilidade e consumo.<\/b><\/span><\/span><\/p>\n

Um carro-teste consome 4,0 kg de biodiesel para realizar trabalho mec\u00e2nico. Se a queima de 1 g de biodiesel libera 5,0 .10<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sup>\u00a0<\/b><\/span><\/span><\/span>cal e o rendimento do motor \u00e9 de 15%, o trabalho mec\u00e2nico realizado, em joules, vale, aproximadamente,<\/b><\/span><\/span>\"\"<\/p>\n

Dado: 1 cal = 4,2 joules<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

\"\"<\/p>\n

05-(UFB)<\/b><\/span><\/span><\/span> A figura anexa \u00e9 o gr\u00e1fico da expans\u00e3o de um g\u00e1s perfeito. Pede-se o trabalho realizado pelo g\u00e1s nas transforma\u00e7\u00f5es:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) AB\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0b) BC\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c) CD\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 e) AD<\/b><\/span><\/span><\/p>\n

 <\/p>\n

06<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span>(UNIFESP-SP)<\/b><\/span><\/span><\/span> O diagrama PV da figura mostra a transi\u00e7\u00e3o de um sistema termodin\u00e2mico de um estado inicial A para o estado final B, segundo tr\u00eas caminhos poss\u00edveis.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

O caminho pelo qual o g\u00e1s realiza o menor trabalho e a express\u00e3o correspondente s\u00e3o, respectivamente,<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

07-(UFRRJ-RJ)<\/b><\/span><\/span><\/span> Um g\u00e1s ideal sofre as transforma\u00e7\u00f5es AB, BC, CD e DA, de acordo com o gr\u00e1fico a seguir.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Atrav\u00e9s da an\u00e1lise do gr\u00e1fico, assinale adiante a alternativa correta.<\/b><\/span><\/span><\/p>\n

a) Na transforma\u00e7\u00e3o CD, o trabalho \u00e9 negativo.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

b) A transforma\u00e7\u00e3o AB \u00e9 isot\u00e9rmica.<\/b><\/span><\/span><\/p>\n

c) Na transforma\u00e7\u00e3o BC, o trabalho \u00e9 negativo.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

d) A transforma\u00e7\u00e3o DA \u00e9 isot\u00e9rmica.<\/b><\/span><\/span><\/p>\n

e) Ao completar o ciclo, a energia interna aumenta.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

08-(UFRRJ-RJ)<\/b><\/span><\/span><\/span> Certa massa gasosa, contida num reservat\u00f3rio, sofre uma transforma\u00e7\u00e3o termodin\u00e2mica no trecho AB. O gr\u00e1fico mostra o comportamento da press\u00e3o P, em fun\u00e7\u00e3o do volume V.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

O m\u00f3dulo do trabalho realizado pelo g\u00e1s, na transforma\u00e7\u00e3o do trecho AB, \u00e9 de:<\/b><\/span><\/span><\/p>\n

a) 400J.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

b) 800J.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

c) 40kJ.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

d) 80kJ.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

e) 600J.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

09-(UFMG-MG)<\/b><\/span><\/span><\/span> Um g\u00e1s ideal, em um estado inicial i, pode ser levado a um estado final f por meio dos processos I, II e III, representados neste diagrama de press\u00e3o versus volume:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Sejam W<\/b><\/span><\/span>I<\/b><\/span><\/span><\/sub>, W<\/b><\/span><\/span>II<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>e W<\/b><\/span><\/span>III<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>os m\u00f3dulos dos trabalhos realizados pelo g\u00e1s nos processos I, II e III, respectivamente.
\nCom base nessas informa\u00e7\u00f5es, \u00e9 correto afirmar que:
\na) W\u00ad<\/b><\/span><\/span>I<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>< W<\/b><\/span><\/span>II<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>< W<\/b><\/span><\/span>III<\/b><\/span><\/span><\/sub>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b) W\u00ad<\/b><\/span><\/span>I<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>= W<\/b><\/span><\/span>II<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>= W<\/b><\/span><\/span>III<\/b><\/span><\/span><\/sub>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c) W\u00ad<\/b><\/span><\/span>I<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>= W<\/b><\/span><\/span>II<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>> W<\/b><\/span><\/span>III<\/b><\/span><\/span><\/sub>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 d) W\u00ad<\/b><\/span><\/span>I<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>> W<\/b><\/span><\/span>II<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>> W<\/b><\/span><\/span>III<\/b><\/span><\/span><\/sub>.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

10-(Uenf-RJ)<\/b><\/span><\/span><\/span> Um g\u00e1s perfeito sofre uma transforma\u00e7\u00e3o que pode ser representada no diagrama abaixo.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

Calcule:<\/b><\/span><\/span><\/p>\n

a) a rela\u00e7\u00e3o entre as temperaturas nos estados<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>A e C<\/b><\/span><\/span>.<\/b><\/span><\/span><\/p>\n

b) o trabalho realizado pelo g\u00e1s na transforma\u00e7\u00e3o<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>ABC<\/b><\/span><\/span>.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

11-(Uneb-Ba)<\/b><\/span><\/span><\/span> Um g\u00e1s ideal sofre uma expans\u00e3o isob\u00e1rica, variando seu volume de 2 m<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sup>at\u00e9 5 m<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sup>. Se o trabalho realizado sobre o g\u00e1s foi de 30J, a press\u00e3o mantida durante a expans\u00e3o, em N\/m<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>, foi de:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

12-(FUVEST-SP)<\/b><\/span><\/span><\/span> A figura mostra o corte transversal de um cilindro de eixo vertical com base de \u00e1rea igual a<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>500cm<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>\u00a0<\/b><\/span><\/span><\/span>, vedado em sua parte superior por um \u00eambolo de massa<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>m<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>que pode deslizar sem atrito.<\/b><\/span><\/span><\/p>\n

O cilindro cont\u00e9m<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>0,50 mol<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>de g\u00e1s que se comporta como ideal. O sistema est\u00e1 em equil\u00edbrio a uma temperatura de<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>300K<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e a altura h, indicada na figura, vale 20cm. Adote para a constante dos gases o valor<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>R = 8,0 J\/mol<\/b><\/span><\/span>, para a acelera\u00e7\u00e3o da gravidade o valor<\/b><\/span><\/span>10m\/s<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>\u00a0<\/b><\/span><\/span><\/span>e para a press\u00e3o atmosf\u00e9rica local o valor<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>1,00 x 10<\/b><\/span><\/span>5<\/b><\/span><\/span><\/sup>N\/m<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>. Determine:<\/b><\/span><\/span><\/p>\n

a) A massa do \u00eambolo em<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>kg<\/b><\/span><\/span>.<\/b><\/span><\/span>\"\"<\/p>\n

b) Determine o trabalho W realizado pelo g\u00e1s quando sua temperatura \u00e9 elevada lentamente at\u00e9<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>420K<\/b><\/span><\/span>.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

13-(UFPE-PE)<\/b><\/span><\/span><\/span> Uma caixa c\u00fabica met\u00e1lica e hermeticamente fechada, de 4,0 cm de aresta, cont\u00e9m g\u00e1s ideal \u00e0 temperatura de 300<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

K e \u00e0 press\u00e3o de 1 atm. Qual a varia\u00e7\u00e3o da for\u00e7a que atua em uma das paredes da caixa, em N, ap\u00f3s o sistema ser aquecido para 330 K e estar em equil\u00edbrio t\u00e9rmico? Despreze a dilata\u00e7\u00e3o t\u00e9rmica do metal.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

14-(UFPE-PE)<\/b><\/span><\/span><\/span> Um cilindro de 20 cm<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>\u00a0<\/b><\/span><\/span><\/span>de se\u00e7\u00e3o reta cont\u00e9m um g\u00e1s ideal comprimido em seu interior por um pist\u00e3o m\u00f3vel, de massa desprez\u00edvel e sem atrito. O pist\u00e3o repousa a uma altura h<\/b><\/span><\/span>o<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>= 1,0 m. A base do cilindro est\u00e1 em contato com um forno, de forma que a temperatura do g\u00e1s permanece constante.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Bolinhas de chumbo s\u00e3o lentamente depositadas sobre o pist\u00e3o at\u00e9 que o mesmo atinja a altura h = 80 cm. Determine a massa de chumbo, em kg, que foi depositado sobre o pist\u00e3o. Considere a press\u00e3o atmosf\u00e9rica igual a 1 atm=10<\/b><\/span><\/span>5<\/b><\/span><\/span><\/sup>N\/m<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup>\u00a0<\/b><\/span><\/span><\/span>e g=10m\/s<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/p>\n

 <\/p>\n

15-(FGV-SP)<\/b><\/span><\/span><\/span> O diagrama relaciona valores de press\u00e3o e volume que ocorrem em determinada m\u00e1quina t\u00e9rmica.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

De sua an\u00e1lise, pode-se inferir que<\/b><\/span><\/span><\/p>\n

a) se a linha 2 fosse uma reta ligando os pontos A e B, ela representaria uma expans\u00e3o isot\u00e9rmica do g\u00e1s.<\/b><\/span><\/span><\/p>\n

b) a \u00e1rea compreendida entre as duas curvas representa o trabalho realizado sobre o g\u00e1s no decorrer de um ciclo completo.<\/b><\/span><\/span><\/p>\n

c) a \u00e1rea formada imediatamente abaixo da linha indicada por 1 e o eixo V equivale, numericamente, ao trabalho \u00fatil realizado pelo g\u00e1s em um ciclo.<\/b><\/span><\/span><\/p>\n

d) o ciclo representa os sucessivos valores de press\u00e3o e volume, que ocorrem em uma m\u00e1quina podendo ser, por exemplo, uma locomotiva a vapor.<\/b><\/span><\/span><\/p>\n

e) no ponto indicado por A, o mecanismo apresenta grande capacidade de realiza\u00e7\u00e3o de trabalho devido aos valores de press\u00e3o e volume que se associam a esse ponto.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

16-(PUC-SP)<\/b><\/span><\/span><\/span> Uma amostra de g\u00e1s ideal sofre o processo termodin\u00e2mico c\u00edclico representado no gr\u00e1fico a seguir.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Ao completar um ciclo, o trabalho, em joules, realizado pela for\u00e7a que o g\u00e1s exerce nas paredes do recipiente \u00e9<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

17-(UERJ-RJ)<\/b><\/span><\/span><\/span> Observe o ciclo mostrado no gr\u00e1fico P \u00d7 V a seguir.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando este ciclo completo, o trabalho realizado, em joules, vale:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

18-(UFC-CE)<\/b><\/span><\/span><\/span> Um g\u00e1s ideal sofre as transforma\u00e7\u00f5es mostradas no diagrama da figura a seguir.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Determine o trabalho total realizado durante os quatro processos termodin\u00e2micos ABCDA.<\/b><\/span><\/span><\/p>\n

19-(CFT-MG)<\/b><\/span><\/span><\/span> O diagrama P \u00d7 V da figura refere-se a um g\u00e1s ideal, passando por uma transforma\u00e7\u00e3o c\u00edclica.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

O ponto em que a temperatura se apresenta mais alta corresponde a __________; e o trabalho realizado pelo g\u00e1s, no processo AB, \u00e9 __________ joules.<\/b><\/span><\/span><\/p>\n

A op\u00e7\u00e3o que completa, corretamente, as lacunas \u00e9<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

20-(UFRGS-RS)<\/b><\/span><\/span><\/span> O gr\u00e1fico a seguir representa o ciclo de uma m\u00e1quina t\u00e9rmica ideal.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

O trabalho total realizado em um ciclo \u00e9<\/b><\/span><\/span><\/p>\n

a) 0 J.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b) 3,0 J.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c) 4,5 J.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 d) 6,0 J.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 e) 9,0 J.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

21-(UEL-PR)<\/b><\/span><\/span><\/span> Uma dada massa de g\u00e1s perfeito realiza uma transforma\u00e7\u00e3o c\u00edclica, como est\u00e1 representada no gr\u00e1fico pV a seguir. O trabalho realizado pelo g\u00e1s ao descrever o ciclo ABCA, em joules, vale:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) 3,0\u00b710<\/b><\/span><\/span>-1<\/b><\/span><\/span><\/sup>.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

b) 4,0\u00b710<\/b><\/span><\/span>-1<\/b><\/span><\/span><\/sup>.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

c) 6,0\u00b710<\/b><\/span><\/span>-1<\/b><\/span><\/span><\/sup>.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

d) 8,0\u00b710<\/b><\/span><\/span>-1<\/b><\/span><\/span><\/sup>.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

e) 9,0\u00b710<\/b><\/span><\/span>-1<\/b><\/span><\/span><\/sup>.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

22-(UECE-CE)\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

No diagrama P-V a seguir, quatro processos termodin\u00e2micos c\u00edclicos executados por um g\u00e1s, com seus respectivos estados iniciais, est\u00e3o representados. O processo no qual o trabalho resultante, realizado pelo g\u00e1s \u00e9 menor \u00e9 o<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

23-(PUC-RJ)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Uma quantidade de g\u00e1s passa da temperatura de 27<\/b><\/span><\/span>o<\/b><\/span><\/span><\/sup>C = 300K a 227<\/b><\/span><\/span>o<\/b><\/span><\/span><\/sup>C = 500K, por um processo a press\u00e3o constante (isob\u00e1rico) igual a 1 atm = 1,0 x 10<\/b><\/span><\/span>5<\/b><\/span><\/span><\/sup>\u00a0<\/b><\/span><\/span><\/span>Pa.<\/b><\/span><\/span><\/p>\n

a) Calcule o volume inicial, sabendo que a massa de g\u00e1s afetada foi de 60 kg e a densidade do g\u00e1s \u00e9 de 1,2 kg\/m<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sup>.<\/b><\/span><\/span><\/p>\n

b) Calcule o volume final e indique se o g\u00e1s sofreu expans\u00e3o ou contra\u00e7\u00e3o.<\/b><\/span><\/span><\/p>\n

c) Calcule o trabalho realizado pelo g\u00e1s.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

24-(UDESC-SC)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um g\u00e1s em uma c\u00e2mara fechada passa pelo ciclo termodin\u00e2mico representado no diagrama p x V da Figura.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

O trabalho, em joules, realizado durante um ciclo \u00e9:<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

25-(UNIOESTE-PR)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A figura abaixo apresenta o diagrama pV para o ciclo fechado de uma m\u00e1quina t\u00e9rmica que usa um g\u00e1s ideal monoat\u00f4mico como subst\u00e2ncia de trabalho. Considerando p<\/b><\/span><\/span>1<\/b><\/span><\/span><\/sub>, p<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>e p<\/b><\/span><\/span>3<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>respectivamente como as press\u00f5es nos pontos 1, 2 e 3, as informa\u00e7\u00f5es da figura e que p<\/b><\/span><\/span>2<\/b><\/span><\/span><\/sub>=5\u00b7p<\/b><\/span><\/span>1<\/b><\/span><\/span><\/sub>, pode-se afirmar:<\/b><\/span><\/span><\/p>\n

I. O processo 1\u21922 \u00e9 isoc\u00f3rico e o processo 3\u21921 isob\u00e1rico.<\/b><\/span><\/span><\/p>\n

II. O trabalho realizado sobre o sistema (g\u00e1s monoat\u00f4mico) no processo 1\u21922 \u00e9 maior que zero joule.<\/b><\/span><\/span><\/p>\n

III. O calor transferido ao sistema (g\u00e1s monoat\u00f4mico) no processo 3\u21921 \u00e9 menor que zero joule.<\/b><\/span><\/span><\/p>\n

IV. A temperatura no ponto 3 \u00e9 5 vezes maior do que aquela no ponto 1.<\/b><\/span><\/span><\/p>\n

V. A varia\u00e7\u00e3o da energia interna do sistema \u00e9 nula no ciclo 1231.<\/b><\/span><\/span><\/p>\n

Considere as afirma\u00e7\u00f5es acima e assinale a alternativa correta.<\/b><\/span><\/span>\"\"<\/p>\n

A. A afirmativa V e falsa.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

B. As alternativas I e II s\u00e3o verdadeiras.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

C. As alternativas I, II e IV s\u00e3o falsas.<\/b><\/span><\/span><\/p>\n

D. Todas as alternativas s\u00e3o falsas.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/p>\n

E. As alternativas I, III e IV s\u00e3o verdadeiras.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

26-UFF-RJ)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O ciclo de Stirling \u00e9 um ciclo termodin\u00e2mico revers\u00edvel\u00a0 utilizado em algumas m\u00e1quinas t\u00e9rmicas. Considere o ciclo de Stirling para 1 mol de um g\u00e1s ideal monoat\u00f4nico ilustrado no diagrama PV.<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

Os processos AB e CD s\u00e3o isot\u00e9rmicos e os processos BC e DA s\u00e3o isoc\u00f3ricos.<\/b><\/span><\/span><\/p>\n

Preencha a tabela para a press\u00e3o, volume e temperatura nos pontos A, B, C, D. Escreva as suas respostas em fun\u00e7\u00e3o de P<\/b><\/span><\/span>A<\/b><\/span><\/span><\/sub>, V<\/b><\/span><\/span>A<\/b><\/span><\/span><\/sub>, P<\/b><\/span><\/span>C<\/b><\/span><\/span><\/sub>, V<\/b><\/span><\/span>C<\/b><\/span><\/span><\/sub>\u00a0<\/b><\/span><\/span><\/span>e<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0de\u00a0 R (constante universal dos gases). Justifique o preenchimento das colunas P & T.<\/b><\/span><\/span><\/p>\n

b) Complete a tabela com os valores do calor absorvido pelo g\u00e1s (Q), da varia\u00e7\u00e3o da sua energia interna (\u0394U) e do trabalho realizado pelo<\/b><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0g\u00e1s (W), medidos em Joule, em cada um dos trechos AB, BC, CD e DA, representados no diagrama PV. Justifique o preenchimento das colunas para Q e \u0394U.<\/b><\/span><\/span><\/p>\n

 <\/p>\n

Confira a resolu\u00e7\u00e3o comentada<\/span><\/a><\/h3>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Exerc\u00edcios de vestibulares com resolu\u00e7\u00e3o comentada sobre Trabalho de um g\u00e1s \u2013 Transforma\u00e7\u00e3o c\u00edclica 01-(UFMS-MS) Sem variar sua massa, um g\u00e1s ideal sofre uma transforma\u00e7\u00e3o a volume constante. \u00c9 correto afirmar que a) a transforma\u00e7\u00e3o \u00e9 isot\u00e9rmica.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b) a transforma\u00e7\u00e3o \u00e9 isob\u00e1rica.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c) o g\u00e1s n\u00e3o realiza trabalho. d) sua press\u00e3o diminuir\u00e1,se a temperatura do g\u00e1s aumentar. e) a varia\u00e7\u00e3o<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2082,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-2084","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2084","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/comments?post=2084"}],"version-history":[{"count":5,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2084\/revisions"}],"predecessor-version":[{"id":10749,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2084\/revisions\/10749"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2082"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=2084"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}