Questões de Vestibular CEDERJ 2019 para Vestibular - Segundo Semestre
Foram encontradas 60 questões
A tabela a seguir fornece um conjunto de dados:
A mediana desse conjunto de dados é igual a
A respeito de um triângulo retângulo cuja medida da hipotenusa é a e cujos catetos medem, na mesma unidade de comprimento, b e c, considere as três afirmações:
I Sendo T1 , T2 e T3 triângulos equiláteros de perímetros 3 a, 3 b e 3 c , respectivamente, a área de T1 é igual à soma das áreas de T2 e T3 .
II A área de um círculo, C1 , de raio com medida a é igual à soma das áreas de dois círculos, C2 e C3 , cujos raios medem b e c , respectivamente.
III A área de um quadrado cujo lado mede a é igual à área do quadrado cujo lado mede (b + c).
É verdadeiro o que é afirmado apenas em
Tem-se uma solução de hidróxido de amônio (Kb = 1.7x10-5) que apresenta um pH igual a 10.00.
A molaridade desta solução é:
O etanol (álcool etílico) tem grande importância na indústria pelo fato de servir como matéria-prima para a produção de outras substâncias. As reações do etanol na produção de outros compostos são dependentes do meio reacional.
A esse respeito, o etanol, quando em
O ácido fumárico é um composto orgânico usado, com muita frequência, pela indústria de alimentos por ser um acidulante que ajuda a prolongar o prazo de validade dos produtos. É comum encontrá-lo em refrigerantes, sucos e geleias. Ele é um ácido dicarboxílico, insaturado, de cadeia normal, também conhecido como ácido donítico, cuja fórmula estrutural é:
Sabendo que na titulação de 30.00 mL de solução deste
ácido foram gastos 60.00 mL de NaOH 0.120 mol/L, sua
molaridade em mol/L é
Os feromônios são usados pelos insetos para se defenderem, encontrarem os parceiros ou acharem comida. Esse acontecimento ocorre sempre entre indivíduos da mesma espécie. O Bombicol foi o primeiro feromônio descrito na literatura Química, tendo sido isolado, em 1959, do bicho-da-seda, ou seja, da lagarta da mariposa Bombyx mori e corresponde à seguinte estrutura:
Em relação à estrutura do Bombicol é correto afirmar que se
trata de um composto de cadeia
O TBT (M.M = 291 g/mol) é um composto polar, hidrofóbico e lipofílico que foi introduzido no mercado nos anos 40. É componente de tintas anti-incrustantes, utilizadas em cascos de barcos, redes e jaulas de aquacultura a fim de impedir a fixação de organismos como algas e invertebrados (mexilhão, cracas, etc.). Além disso, o TBT é utilizado também na agricultura como pesticida, conservante de madeiras e, numa escala menor, em desinfetantes e em tratamentos algicidas em materiais de construção. A sua elevada difusão no meio marinho tornou-se uma preocupação ambiental em nível mundial. Atualmente, é considerada a substância mais tóxica produzida pelo homem.
A composição centesimal do TBT é de 49.49% de Carbono, 9.62% de Hidrogênio e 40.89% de Estanho e sua fórmula molecular é:
O Cardanol é um fenol obtido do líquido da castanha de caju (LCC), a partir do processo de aquecimento a que as castanhas são submetidas para fins alimentícios, de modo a romper a casca externa e liberar o óleo.
Sendo o LCC um subproduto de agronegócio do caju e
correspondente a, aproximadamente, 25% do peso da castanha, supõe-se que 5% desse líquido seja o ácido anacárdico. Assim, para produzir 5.96 toneladas de Cardanol,
supondo que sua massa molar seja de aproximadamente,
298 g/mol, a quantidade necessária de castanhas em toneladas é de:
Big Tech made the social media mess. It has to fix it
Analysis by David Goldman, CNN Business
Social media has given people a platform to spew hate speech and radical beliefs to other people, amplifying what are otherwise fringe opinions. A few have turned that hate into violence.
Silicon Valley has built the biggest, most powerful companies in the world. Now, tech leaders have a responsibility to rein in the creations that have grown too unwieldy for them to control.
These are businesses, and their leaders will have to And out how to do that without destroying their companies. So far, balancing Big Tech's responsibilities to society and its duties to investors has proven difficult.
A difficult balance
Facebook (FB) announced in July it would invest billions of dollars a year to improve safety and security on the platform. The company said the effort would come at the expense of user growth and profitability. The company's stock lost about a third of its value because investors were concerned about Facebook's growth stalling.
Twitter has largely rid ISIS recruiters from the social network. Facebook and YouTube have labeled fake news stories as such. Yet, the work isn't close to done. Google has also made significant changes to YouTube's advertising policies after ads from 300 companies and organizations ran on channels promoting hate groups.
"YouTube has strict policies that prohibit content which incites others to violence or promotes hatred," a YouTube spokesperson said. "We quickly remove videos violating our policies when flagged by our users."
What seemed to cross no one's mind a decade ago was the potential downside to building a platform with billions of customers. So many posts can't possibly be monitored in real time. The networks gave the dregs of society the ability to reach like-minded people and poison the minds of others.
Without that foresight, Silicon Valley allowed their creations to break down. They're not beyond repair, but fixing them will be costly and difficult. Whether Big Tech is up to the task will determine the fates of their platforms.
Available: https://edition.cnn.com/2018/10/29/tech/social-media- -hate-speech/index.html. Access: 30 may 2019. Adapted.
Glossary: spew: lançar; fringe: periféricas; to rein in: controlar; unwieldy: desordenado; duties: deveres; profitability, lucro;
stock: ação (no mercado); stalling: interrupção; flagged: sinalizados; dregs of society: pessoas inescrupulosas; like-minded: pessoas que compartilham ideias semelhantes; poison: envenenar;
foresight: visão; beyond repair: sem conserto; up to the task: à
altura da tarefa.
Big Tech made the social media mess. It has to fix it
Analysis by David Goldman, CNN Business
Social media has given people a platform to spew hate speech and radical beliefs to other people, amplifying what are otherwise fringe opinions. A few have turned that hate into violence.
Silicon Valley has built the biggest, most powerful companies in the world. Now, tech leaders have a responsibility to rein in the creations that have grown too unwieldy for them to control.
These are businesses, and their leaders will have to And out how to do that without destroying their companies. So far, balancing Big Tech's responsibilities to society and its duties to investors has proven difficult.
A difficult balance
Facebook (FB) announced in July it would invest billions of dollars a year to improve safety and security on the platform. The company said the effort would come at the expense of user growth and profitability. The company's stock lost about a third of its value because investors were concerned about Facebook's growth stalling.
Twitter has largely rid ISIS recruiters from the social network. Facebook and YouTube have labeled fake news stories as such. Yet, the work isn't close to done. Google has also made significant changes to YouTube's advertising policies after ads from 300 companies and organizations ran on channels promoting hate groups.
"YouTube has strict policies that prohibit content which incites others to violence or promotes hatred," a YouTube spokesperson said. "We quickly remove videos violating our policies when flagged by our users."
What seemed to cross no one's mind a decade ago was the potential downside to building a platform with billions of customers. So many posts can't possibly be monitored in real time. The networks gave the dregs of society the ability to reach like-minded people and poison the minds of others.
Without that foresight, Silicon Valley allowed their creations to break down. They're not beyond repair, but fixing them will be costly and difficult. Whether Big Tech is up to the task will determine the fates of their platforms.
Available: https://edition.cnn.com/2018/10/29/tech/social-media- -hate-speech/index.html. Access: 30 may 2019. Adapted.
Glossary: spew: lançar; fringe: periféricas; to rein in: controlar; unwieldy: desordenado; duties: deveres; profitability, lucro;
stock: ação (no mercado); stalling: interrupção; flagged: sinalizados; dregs of society: pessoas inescrupulosas; like-minded: pessoas que compartilham ideias semelhantes; poison: envenenar;
foresight: visão; beyond repair: sem conserto; up to the task: à
altura da tarefa.
Big Tech made the social media mess. It has to fix it
Analysis by David Goldman, CNN Business
Social media has given people a platform to spew hate speech and radical beliefs to other people, amplifying what are otherwise fringe opinions. A few have turned that hate into violence.
Silicon Valley has built the biggest, most powerful companies in the world. Now, tech leaders have a responsibility to rein in the creations that have grown too unwieldy for them to control.
These are businesses, and their leaders will have to And out how to do that without destroying their companies. So far, balancing Big Tech's responsibilities to society and its duties to investors has proven difficult.
A difficult balance
Facebook (FB) announced in July it would invest billions of dollars a year to improve safety and security on the platform. The company said the effort would come at the expense of user growth and profitability. The company's stock lost about a third of its value because investors were concerned about Facebook's growth stalling.
Twitter has largely rid ISIS recruiters from the social network. Facebook and YouTube have labeled fake news stories as such. Yet, the work isn't close to done. Google has also made significant changes to YouTube's advertising policies after ads from 300 companies and organizations ran on channels promoting hate groups.
"YouTube has strict policies that prohibit content which incites others to violence or promotes hatred," a YouTube spokesperson said. "We quickly remove videos violating our policies when flagged by our users."
What seemed to cross no one's mind a decade ago was the potential downside to building a platform with billions of customers. So many posts can't possibly be monitored in real time. The networks gave the dregs of society the ability to reach like-minded people and poison the minds of others.
Without that foresight, Silicon Valley allowed their creations to break down. They're not beyond repair, but fixing them will be costly and difficult. Whether Big Tech is up to the task will determine the fates of their platforms.
Available: https://edition.cnn.com/2018/10/29/tech/social-media- -hate-speech/index.html. Access: 30 may 2019. Adapted.
Glossary: spew: lançar; fringe: periféricas; to rein in: controlar; unwieldy: desordenado; duties: deveres; profitability, lucro;
stock: ação (no mercado); stalling: interrupção; flagged: sinalizados; dregs of society: pessoas inescrupulosas; like-minded: pessoas que compartilham ideias semelhantes; poison: envenenar;
foresight: visão; beyond repair: sem conserto; up to the task: à
altura da tarefa.
Big Tech made the social media mess. It has to fix it
Analysis by David Goldman, CNN Business
Social media has given people a platform to spew hate speech and radical beliefs to other people, amplifying what are otherwise fringe opinions. A few have turned that hate into violence.
Silicon Valley has built the biggest, most powerful companies in the world. Now, tech leaders have a responsibility to rein in the creations that have grown too unwieldy for them to control.
These are businesses, and their leaders will have to And out how to do that without destroying their companies. So far, balancing Big Tech's responsibilities to society and its duties to investors has proven difficult.
A difficult balance
Facebook (FB) announced in July it would invest billions of dollars a year to improve safety and security on the platform. The company said the effort would come at the expense of user growth and profitability. The company's stock lost about a third of its value because investors were concerned about Facebook's growth stalling.
Twitter has largely rid ISIS recruiters from the social network. Facebook and YouTube have labeled fake news stories as such. Yet, the work isn't close to done. Google has also made significant changes to YouTube's advertising policies after ads from 300 companies and organizations ran on channels promoting hate groups.
"YouTube has strict policies that prohibit content which incites others to violence or promotes hatred," a YouTube spokesperson said. "We quickly remove videos violating our policies when flagged by our users."
What seemed to cross no one's mind a decade ago was the potential downside to building a platform with billions of customers. So many posts can't possibly be monitored in real time. The networks gave the dregs of society the ability to reach like-minded people and poison the minds of others.
Without that foresight, Silicon Valley allowed their creations to break down. They're not beyond repair, but fixing them will be costly and difficult. Whether Big Tech is up to the task will determine the fates of their platforms.
Available: https://edition.cnn.com/2018/10/29/tech/social-media- -hate-speech/index.html. Access: 30 may 2019. Adapted.
Glossary: spew: lançar; fringe: periféricas; to rein in: controlar; unwieldy: desordenado; duties: deveres; profitability, lucro;
stock: ação (no mercado); stalling: interrupção; flagged: sinalizados; dregs of society: pessoas inescrupulosas; like-minded: pessoas que compartilham ideias semelhantes; poison: envenenar;
foresight: visão; beyond repair: sem conserto; up to the task: à
altura da tarefa.
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