k có giá trị nào hết vì vế trái luôn lớn hơn hoặc bằng 12

Đốt cháy hoàn toàn hỗn hợp X gồm glucozo, saccarozo, tinh bột và xenlulozo cần 13,44 lít khí O₂ (đktc). Dẫn toàn bộ khí CO₂ sinh ra vào dung dịch Ba(OH)₂ dư được m gam kết tủ a trắng. Tính giá trị của m.

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mik chắc chắn,bạn k tin thử lại đi

VIO ak?

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 below.

Because writing has become so important in our culture, we sometimes think of it as more real than speech. A little thought, however, will show why speech is primary and writing secondary to language. Human beings have been writing (as far as we can tell from surviving evidence) for at least 5000 years; but they have been talking for much longer, doubtless ever since there have been human beings.

When writing did develop, it was derived from and represented speech, although imperfectly. Even today there are spoken languages that have no written form. Furthermore, we all learn to talk well before we learn to write; any human child who is not severely handicapped physically or mentally will learn to talk. a normal human being cannot be prevented from doing so. On the other hand, it takes a special effort to learn to write. In the past many intelligent and useful members of society did not acquire the skill, and even today many who speak languages with writing systems never learn to read or write, while some who learn the rudiments of those skills do so only imperfectly.

To affirm the primacy of speech over writing is not, however, to disparage the latter. One advantage writing has over speech is that it is more permanent and makes possible the records that any civilization must have. Thus, if speaking makes us human, writing makes us civilized.

We sometimes think of writing as more real than speech because ______.

A. writing is secondary to language

B. human beings have been writing for at least 5000 years

C. it has become very important in our culture

D. people have been writing since there have been human beings

Hỗn hợp P gồm ancol A, axit cacboxylic B (đều no, đơn chức, mạch hở) và este C tạo ra từ A và B. Đốt cháy hoàn toàn m gam P cần dùng vừa đủ 0,36 mol O₂, sinh ra 0,28 mol CO₂. Cho m gam P trên vào 250 ml dung dịch NaOH 0,4M đun nóng, sau khi kết thúc các phản ứng thu được dung dịch Q. Cô cạn dung dịch Q còn lại 7,36 gam chất rắn khan. Người ta cho thêm bột CaO và 0,96 gam NaOH vào 7,36 gam chất rắn khan trên rồi nung trong bình kín không có không khí đến phản ứng hoàn toàn thu được a gam khí. Giá trị của a gần nhất với giá trị nào sau đây?

A. 2,5

B. 2,9

C. 2,1

D. 1,7