2)chỉ được dùng 1 thuốc thử phân biệt

a)FeCl2,MgCl3,FeCl3,ZnCl2,KCl,CuCl2

b)BaCl2,NaCl,H2SO4,HCl

1)khi cho 2.2g CO2 vào dung dịch nước với dự.Tính khối lượng kết tủa thu được

3)cho các chất sau:CuSO4,Mg(NO3)2,NH4CL,HCl:dung dịch nào khi tác dụng với NaOH sẽ

-tao chất kết tủa màu xanh lam

-tạo chất kết tủa trắng keo không tan trong NaOH

-tạo khí có mùi khai

1)cho các chất sau: Cú,CuO,Mg,CaCO3,Al2O3,Fe2O3,Fe(OH)2,Zn

a)Hãy cho biết chất nào tác dụng với H2SO4 loãng sinh ra và viết phương trình hóa học

-khí nhẹ hơn không khí và cháy trong không khí

-khí nặng hơn không khí và không cháy trong không khí

-dung dịch màu xanh lam,không có khí thoát ra

-dung dịch màu vàng nâu,không có khí thoát ra

-dung dịch không màu,không có khí thoát ra

b) dùng phản ứng hóa học nào thì có thể phân biệt được 2 chất rắn là Fe2O3 và Al2O3

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Lập công thức của một õit thành phần gồm 10% Fe

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 3 to 9.

        Most people can remember a phone number for up to thirty seconds. When this short amount of time elapses, however, the numbers are erased from the memory. How did the information get there in the first place? Information that makes its way to the short term memory (STM) does so via the sensory storage area. The brain has a filter which only allows stimuli that is of immediate interest to pass on to the STM, also known as the working memory.

        There is much debate about the capacity and duration of the short term memory. The most accepted theory comes from George A. Miller, a cognitive psychologist who suggested that humans can remember approximately seven chunks of information. A chunk is defined as a meaningful unit of information, such as a word or name rather than just a letter or number. Modern theorists suggest that one can increase the capacity of the short term memory by chunking, or classifying similar information together. By organizing information, one can optimize the STM, and improve the chances of a memory being passed on to long term storage.

        When making a conscious effort to memorize something, such as information for an exam, many people engage in "rote rehearsal". By repeating something over and over again, one is able to keep a memory alive. Unfortunately, this type of memory maintenance only succeeds if there are no interruptions. As soon as a person stops rehearsing the information, it has the tendency to disappear. When a pen and paper are not handy, people often attempt to remember a phone number by repeating it aloud. If the doorbell rings or the dog barks to come in before a person has the opportunity to make a phone call, he will likely forget the number instantly. Therefore, rote rehearsal is not an efficient way to pass information from the short term to long term memory. A better way is to practice "elaborate rehearsal". This involves assigning semantic meaning to a piece of information so that it can be filed along with other pre-existing long term memories.

          Encoding information semantically also makes it more retrievable. Retrieving information can be done by recognition or recall. Humans can easily recall memories that are stored in the long term memory and used often; however, if a memory seems to be forgotten, it may eventually be retrieved by prompting. The more cues a person is given (such as pictures), the more likely a memory can be retrieved. This is why multiple choice tests are often used for subjects that require a lot of memorization.

The word “This” in paragraph 3 most probably refers to ______.

A. information

B. long-term memory

C. a better way

D. elaborate rehearsal

Read the following andmark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 22 to 29.

Harvard University, today recognized as part of the top echelon of the world's universities, came from very inauspicious and humble beginning.

This oldest of American universities was founded in 1636, just sixteen years after the Pilgrims landed at Plymouth. Included in the Puritan emigrants to the Massachusetts colony during this period were more than 100 graduates of England's prestigious Oxford and Cambridge universities, and these universities graduates in the New Word were determined that their sons would have the same educational opportunities that they themselves had had. Because of this support in the colony for an institution of higher learning, the General

Court of Massachusetts appropriated 400 pounds for a college in October of 1636 and early the following year decided on a parcel of land for the school; this land was in an area called Newetowne, which was later renamed Cambridge after its English cousin and is the site of the present-day university.

When a young minister named John Harvard, who came from the neighboring town of Charlestowne, died from tuberculosis in 1638, he willed half of his estate of 1,700 pounds to the fledgling college. In spite of the fact that only half of the bequest was actually paid, the General Court named the college after the minister in appreciation for what he had done. The amount of the bequest may not have been large, particularly by today's standard, but it was more than the General Court had found it necessary to appropriate in order to open the college.

Henry Dunster was appointed the first president of Harvard in 1640, and it should be noted that in addition to serving as president, he was also the entire faculty, with an entering freshmen class of four students. Although the staff did expand somewhat, for the first century of its existence the entire teaching staff consisted of the president and three or four tutors

The word "somewhat" in the last paragraph could best be replaced by _______

A. to and pro

B. Back and forth

C. side by side

D. more or less

Read the following andmark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 22 to 29.

Harvard University, today recognized as part of the top echelon of the world's universities, came from very inauspicious and humble beginning.

This oldest of American universities was founded in 1636, just sixteen years after the Pilgrims landed at Plymouth. Included in the Puritan emigrants to the Massachusetts colony during this period were more than 100 graduates of England's prestigious Oxford and Cambridge universities, and these universities graduates in the New Word were determined that their sons would have the same educational opportunities that they themselves had had. Because of this support in the colony for an institution of higher learning, the General

Court of Massachusetts appropriated 400 pounds for a college in October of 1636 and early the following year decided on a parcel of land for the school; this land was in an area called Newetowne, which was later renamed Cambridge after its English cousin and is the site of the present-day university.

When a young minister named John Harvard, who came from the neighboring town of Charlestowne, died from tuberculosis in 1638, he willed half of his estate of 1,700 pounds to the fledgling college. In spite of the fact that only half of the bequest was actually paid, the General Court named the college after the minister in appreciation for what he had done. The amount of the bequest may not have been large, particularly by today's standard, but it was more than the General Court had found it necessary to appropriate in order to open the college.

Henry Dunster was appointed the first president of Harvard in 1640, and it should be noted that in addition to serving as president, he was also the entire faculty, with an entering freshmen class of four students. Although the staff did expand somewhat, for the first century of its existence the entire teaching staff consisted of the president and three or four tutors

The passage implies that __________________ .

A. Someone else really served as president of Harvard before Henry Dunster

B. Henry Dunster was an ineffective president

C. Henry Dunster spent much of his time as president managing the Harvard faculty

D. The position of president of Harvard was not merely an administrative position in the early ears

Tìm các ước của các số sau:

a) 12

b) 15

c) 76

d) 124

Cho  A = 1 ; 2 ; 4 ; 7 ;               A ∪ B = 1 ; 2 ; 3 ; 4 ; 5 ; 7   ;           A ∩ B = 2 ; 7

Hãy xác định B