Điện phân (điện cực trơ, màng ngăn xốp) dung dịch gồm CuSO₄ và NaCl (tỉ lệ mol tương ứng 1 : 3) với cường độ dòng diện 1,34A. Sau thời gian t giờ, thu được dung dịch Y (chứa hai chất tan) có khối lượng giảm 10,375 gam so với dung dịch ban đầu. Cho bột Al dư vào Y, thu được 1,68 lít khí H₂ (đktc). Biết các phản ứng xảy ra hoàn toàn, hiệu suất điện phân 100%, bỏ qua sự hòa tan của khí trong nước và sự bay hơi của nước. Giá trị của t là

A. 4.

B. 7

C. 5.

D. 6

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 46 to 50.

Madonna

Ever since she burnt onto the pop scene in the early eighties, Madonna has remained one of the most well-known celebrities in the world. She has shown herself to be a talented singer, songwriter and actress. To have achieved this she undoubtedly has a strong belief in herself and abilities.

It is possible she gained her strong personality through her touch childhood experiences. She went to a strict catholic school, was one of many children, and her family was split up after her mother died from cancer. Eventually, in search of fame, she left college and went to New York with only her suitcase and a few dollars.

Hugely successful, often through controversy, Madonna has always known what the public and media want. She has gone from shocking clothes and pop songs to setting trends and family life. She caused disagreement by playing feminist roles in films and featuring in pop videos with imagines of Jesus Christ.

Throughout all her years and different styles and phrases, she has always been able to give the general public entertainment. Madonna has become one of the biggest stars on the planet, and has sold over 100 million records worldwide, making her one of the highest-earning entertainers of her generation.

Even now as she approaches fifty and is a mother, Madonna is likely to contribute to entertain us for many more years, but what nobody can be sure of is exactly what she will do next!

What is the writer’s main purpose in writing this text?

A. To discuss Madonna’s acting career, and encourage other pop stars to go into acting.

B. To show how well Madonna has achieved successes throughout the years.

C. To remind people that money is not everything, and it comes and goes

D. To claim that fashion always changes, and no one can stay famous forever

Read the following passage and blacken the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

A small but growing group of scholar, evolutionary, psychologists, are being to sketch the contours of the human mind as designed by natural selection. Some of them even anticipate the coming of a field called "mismatch theory", which would study maladies resulting from contrasts between the modern environment and the "ancestral environment". The one we were designed for.

There is no shortage of such maladies to study, Rates of depression have been doubling in some industrial countries roughly every 10 years. Suicide is the third most common cause of death among young adults, after car wrecks and homicides.

Evolutionary psychology is a long way from explaining all this with precision, but it is already shedding enough light to challenges some conventional wisdom. It suggests, for example, that the nostalgia for the nuclear family of the 1950s is in some way misguided - that the model family of husband at work and wife

at home is hardly a "natural" and healthful living arrangement, especially for the wives. Moreover, the bygone lifestyles that do look fairly natural in light of evolutionary psychology appear to have been eroded largely by commercialism. Perhaps the biggest surprise from evolutionary psychology it its depiction of the "animal" in us. Freud, and various thinkers since, saw "civilization" as an oppressive force that thwarts basic animal instincts and urges and transmutes them into psychopathology. However, evolutionary psychology suggests that a larger threat to metal health may be the way civilization thwarts civility. There is a gentler, kinder side of human nature, and it seems increasingly to be a victim of repression in modern society.

Question: Which of the following is the main topic of the passage?

A.  How evolutionary psychology manages modern society.

B.  The problems of illness caused by modern society.

C.  The importance of ancestral environment.

D.  Evolutionary psychologists' views on the nuclear family.

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