(FUVEST - 2005 - 1 FASE) Uma soluo aquosa de penicilina sofre degradao com o tempo, perdendosua atividade antibitica. Para determinar o prazo de validade dessa soluo, sua capacidadeantibitica foi medida em unidades de penicilina G*. Os resultados das medidas, obtidosdurante sete semanas, esto no grfico. * Uma unidade de penicilina G corresponde a 0,6 g dessa substncia. Supondo-se como aceitvel uma atividade de 90% da inicial, o prazo de validade da soluoseria de
(FUVEST - 2005 - 1 FASE) Utilizando um pulso de laser*, dirigido contra um anteparo de ouro, cientistasbritnicos conseguiram gerar radiao gama suficientemente energtica para, atuando sobreum certo nmero de ncleos de iodo-129, transmut-los em iodo-128, por liberao denutrons. A partir de 38,7 g de iodo-129, cada pulso produziu cerca de 3 milhes de ncleos deiodo-128. Para que todos os ncleos de iodo-129 dessa amostra pudessem ser transmutados,seriam necessrios x pulsos, em que x Dado: constante de Avogadro = 6,0 1023mol-1. *laser = fonte de luz intensa
(FUVEST - 2005 - 1 FASE)Em gua, o aminocido alanina pode ser protonado, formando um ction que ser designado por ala+; pode ceder prton, formando um nion designado por ala. Dessa forma, os seguintes equilbrios podem ser escritos: A concentrao relativa dessas espcies depende do pH da soluo, como mostrado no grfico. Quando [ala] = 0,08 mol L1, [ala+] = 0,02 mol L1 e [ala] for desprezvel, a concentrao hidrogeninica na soluo, em mol L1, ser aproximadamente igual a
(FUVEST - 2005 - 1 FASE) Constituindo fraldas descartveis, h um polmero capaz de absorver grande quantidade de gua por um fenmeno de osmose, em que a membrana semipermevel o prprio polmero. Dentre as estruturas aquela que corresponde ao polmero adequado para essa finalidade a do
(FUVEST - 2005 - 1 FASE) Nitrato de cobre bastante utilizado nas indstrias grficas e txteis e pode ser preparado por trs mtodos: - Mtodo I: Cu(s) + ...HNO3(conc.) Cu(NO3)2(aq) + ... NO2(g) + ...H2O() - Mtodo II: 2 Cu(s) + O2(g) 2 CuO(s) 2 CuO(s) + ...HNO3(dil.) 2 Cu(NO3)2(aq) + ...H2O() - Mtodo III: 3Cu(s)+ ...HNO3(dil.) 3 Cu(NO3)2(aq)+ ...NO(g) + 4 H2O() 2 NO(g) + O2(g) 2 NO2(g) Para um mesmo consumo de cobre,
(Fuvest 2005) Com a finalidade de niquelar uma pea de lato, foi montado um circuito, utilizando-se fonte de corrente contnua, como representado na figura. No entanto, devido a erros experimentais, ao fechar o circuito, no ocorreu a niquelao da pea. Para que essa ocorresse, foram sugeridas as alteraes: I - Inverter a polaridade da fonte de corrente contnua. II - Substituir a soluo aquosa de NaC por soluo aquosa de NiSO4. III - Substituir a fonte de corrente contnua por uma fonte de corrente alternada de alta frequncia. O xito do experimento requereria apenas
(FUVEST - 2005 - 1 FASE) Em um experimento, para determinar o nmero x de grupos carboxlicos namolcula de um cido carboxlico, volumes de solues aquosas desse cido e de hidrxido desdio, de mesma concentrao, em mol L-1, mesma temperatura, foram misturados de talforma que o volume final fosse sempre 60 mL. Em cada caso, houve liberao de calor. Nogrfico a seguir, esto as variaes de temperatura (T) em funo dos volumes de cido ebase empregados: Partindo desses dados, pode-se concluir que o valor de x Nesse experimento, o calor envolvido na dissociao do cido e o calor de diluio podem serconsiderados desprezveis.
(FUVEST - 2005 - 1 FASE) Os hidrocarbonetos ismeros antraceno e fenantreno diferem em suas entalpias (energias). Esta diferena de entalpia pode ser calculada, medindo-se o calor de combusto total desses compostos em idnticas condies de presso e temperatura. Para o antraceno, h liberao de 7060 kJ mol-1 e para o fenantreno, h liberao de 7040 kJ mol-1. Sendo assim, para 10 mols de cada composto, a diferena de entalpia igual a
(FUVEST - 2005 - 1 FASE) O Brasil produz, anualmente, cerca de 6 x 106 toneladas de cido sulfrico pelo processo de contacto. Em uma das etapas do processo h, em fase gasosa, o equilbrio que se estabelece presso total de P atm e temperatura constante. Nessa temperatura, para que o valor da relao seja igual a 6,0 x 104, o valor de P deve ser
(FUVEST - 2005 - 1 FASE) Uma soluo aquosa de NaOH (base forte), de concentrao 0,10 mol L-1, foigradualmente adicionada a uma soluo aquosa de HCℓ (cido forte), de concentrao 0,08mol L-1. O grfico que fornece as concentraes das diferentes espcies, durante essa adio
(FUVEST - 2005 - 1 FASE) A acetilcolina (neurotransmissor) um composto que, em organismos vivos e pela ao de enzimas, transformado e posteriormente regenerado: Na etapa 1, ocorre uma transesterificao. Nas etapas 2 e 3, ocorrem, respectivamente,
(FUVEST - 2005 - 1 FASE)Christoph Oswald has no problem approaching women. As he makes his way through the crowd at his favorite Frankfurt club, his cell phone scans a 10-meter radius for his type: tall, slim, sporty, in her 30s-and, most important, looking for him, a handsome 36-year-old software consultant who loves ski holidays. Before he reaches the bar, his phone starts vibrating and an attractive blonde appears on its screen. Hi, Im Susan, she says. Come find me! Christoph picks her out of the crowd, and soon theyre laughing over a drink. Both Christoph and Susan have phones equipped with Symbian Dater, a program that promises to turn the cell phone into a matchmaker. By downloading Symbian, they installed a 20-character encrypted code that includes details of who they are and what theyre looking for in a mate. Whenever they go out, their matchmaking phones sniff out other Symbian Daters over the unlicensed, and therefore free, Bluetooth radio frequency. If profiles match up, the phones beep wildly and send out short video messages. (NEWSWEEK, JUNE 7 / JUNE 14, 2004) The passage tells us that at his favorite Frankfurt club, Christoph Oswald
(FUVEST - 2005 - 1 FASE)Christoph Oswald has no problem approaching women. As he makes his way through the crowd at his favorite Frankfurt club, his cell phone scans a 10-meter radius for his type: tall, slim, sporty, in her 30s-and, most important, looking for him, a handsome 36-year-old software consultant who loves ski holidays. Before he reaches the bar, his phone starts vibrating and an attractive blonde appears on its screen. Hi, Im Susan, she says. Come find me! Christoph picks her out of the crowd, and soon theyre laughing over a drink. Both Christoph and Susan have phones equipped with Symbian Dater, a program that promises to turn the cell phone into a matchmaker. By downloading Symbian, they installed a 20-character encrypted code that includes details of who they are and what theyre looking for in a mate. Whenever they go out, their matchmaking phones sniff out other Symbian Daters over the unlicensed, and therefore free, Bluetooth radio frequency. If profiles match up, the phones beep wildly and send out short video messages. (NEWSWEEK, JUNE 7 / JUNE 14, 2004) According to the passage, Symbian Dater is a program that
(FUVEST - 2005 - 1 FASE)Christoph Oswald has no problem approaching women. As he makes his way through the crowd at his favorite Frankfurt club, his cell phone scans a 10-meter radius for his type: tall, slim, sporty, in her 30s-and, most important, looking for him, a handsome 36-year-old software consultant who loves ski holidays. Before he reaches the bar, his phone starts vibrating and an attractive blonde appears on its screen. Hi, Im Susan, she says. Come find me! Christoph picks her out of the crowd, and soon theyre laughing over a drink. Both Christoph and Susan have phones equipped with Symbian Dater, a program that promises to turn the cell phone into a matchmaker. By downloading Symbian, they installed a 20-character encrypted code that includes details of who they are and what theyre looking for in a mate. Whenever they go out, their matchmaking phones sniff out other Symbian Daters over the unlicensed, and therefore free, Bluetooth radio frequency. If profiles match up, the phones beep wildly and send out short video messages. (NEWSWEEK, JUNE 7 / JUNE 14, 2004) In the passage, the correct translation for picks her out is
(FUVEST - 2005 - 1 FASE)Christoph Oswald has no problem approaching women. As he makes his way through the crowd at his favorite Frankfurt club, his cell phone scans a 10-meter radius for his type: tall, slim, sporty, in her 30s-and, most important, looking for him, a handsome 36-year-old software consultant who loves ski holidays. Before he reaches the bar, his phone starts vibrating and an attractive blonde appears on its screen. Hi, Im Susan, she says. Come find me! Christoph picks her out of the crowd, and soon theyre laughing over a drink. Both Christoph and Susan have phones equipped with Symbian Dater, a program that promises to turn the cell phone into a matchmaker. By downloading Symbian, they installed a 20-character encrypted code that includes details of who they are and what theyre looking for in a mate. Whenever they go out, their matchmaking phones sniff out other Symbian Daters over the unlicensed, and therefore free, Bluetooth radio frequency. If profiles match up, the phones beep wildly and send out short video messages. (NEWSWEEK, JUNE 7 / JUNE 14, 2004) We can conclude from the passage that Christoph Oswald