Sử dụng công cụ  để vẽ hình minh hoa Hệ Mặt Trời theo mẫu ở hình 49 sau đây (có thể mở tệp Hinhelip1.bmp để so sánh):

Cho hỗn hợp Na và Al có tỉ lệ số mol tương ứng là 1 : 2 vào nước dư. Sau khi các phản ứng xảy ra hoàn toàn thu được 8,96 lít H₂ (đktc) và m gam chất rắn không tan. Giá trị của m là

A. 7,8 gam.

B. 5,4 gam.

C. 43,2 gam.

D. 10,8 gam.

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

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes.

These trails incorporate no directional information and may be followed by other ants in either direction.Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth.

The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

What does the passage mainly discuss?

A. The mass migration of ants   

B. How ants mark and follow a chemical trail 

C. Different species of ants around the world 

D. The information contained in pheromones

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.

A. vision     

B. conclusion              

C. division                  

D. comparison

Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
I _________ to see Chris on my way home.

A. dropped back

B. dropped in

C. dropped out

D. dropped off

Khi cân một vật với độ chính xác đến 0,05kg, người ta cho biết kết quả là 26,4kg. Hãy chỉ ra khối lượng thực của vật đó nằm trong khoảng nào?

Hòa tan hoàn toàn m gam ZnSO₄ vào nước được dung dịch X. Nếu cho 110 ml dung dịch KOH 2M vào X (TN1) thì thu được 3a gam kết tủa. Mặt khác, nếu cho 140 ml dung dịch KOH 2M vào X (TN2) thì thu được 2a gam kết tủa. Giá trị của m là : 

A. 17,71.

B. 16,10.      

C. 32,20

D. 24,15.