Bạn tự chỉ ra tỉ lệ số nguyên tử, phân tử của các chất trong pư nhé!

1/ \(4Na+O_2\underrightarrow{t^o}2Na_2O\)

2/ \(2Al+3Cl_2\underrightarrow{t^o}2AlCl_3\)

3/ \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

4/ \(P_2O_5+3H_2O\rightarrow2H_3PO_4\)

5/ \(Mg+\dfrac{1}{2}O_2\underrightarrow{t^o}MgO\)

6/ \(Cu+2H_2SO_{4\left(đ\right)}\underrightarrow{t^o}CuSO_4+SO_2+2H_2O\)

7/ \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)

8/ \(Fe_2O_3+3CO\underrightarrow{t^o}2Fe+3CO_2\)

9/ \(4Na+O_2\underrightarrow{t^o}2Na_2O\)

10/ \(CaCO_3\underrightarrow{t^o}CaO+CO_2\)

11/ \(Mg+2HCl\rightarrow MgCl_2+H_2\)

12/ \(Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)

13/ \(xAl+yCuSO_4\rightarrow Al_x\left(SO_4\right)_y+yCu\)

14/ \(Fe_xO_y+yCO\underrightarrow{t^o}xFe+yCO_2\)

15/ \(6NaOH+Fe_2\left(SO_4\right)_3\rightarrow2Fe\left(OH\right)_{3\downarrow}+3Na_2SO_4\)

Bạn tham khảo nhé!

275,6:3,2=86,125

55,08:1,8=30.6

Cậu đặt tính rồi tính giúp tớ với

My family is going to visit my grandparents in Kien Giang in next summer. I’m looking forward to seeing them and their beautiful house that I love so much. That’s an ancient small French villa with a chimney and many old arc windows. The house is light blue that is my favourite colour. There are two floors and a terrace in the house. A living room and a kitchen are in the first floor. My grandfather put a sofa made from wood, an out-dated telvevision and a small aquarium with many colorful schools of fish. Behind the living room is the kitchen. The stuffs in the kitchen are quite old, exception gas stove and refrigerator. My grandmother told me that she had a lot of experiences in this kitchen because she almost spent all of her life to do household chorces and cooking. Next to the kitchen is a cute henhouse where grandmom often takes eggs to bake a best cake ever. There are 3 bedrooms and a workship room where is kept clean all the time in the second floor. The bedroom is very simple and corny. I have to admit that the bedroom looks very musky. When I was a kid, I always thought of scary things would happen to me if I fell asleep in a bedroom that. And nothing happened to me, of course, that’s just my imagination. The last part of the house is the terrace which is my grandfather’s world. He has many strange beautiful birds whose names are difficult to remember, too. He lets the birds land in the trees which he planted a long time ago. Every morning, my grandparents do exercises and enjoy the fresh air there together. To everyone, that house may be very normal but to me that is the most perfect house in the world. 

k mình nhá

Hello, everybody . Today, I will tell you about my house. I live in a small house and it s a very beautiful . There are five rooms in my house .It has a living room, a kitchen, two bedrooms and one bathrooms. In the living room, there is a table, four chairs, a television, a window . My bedroom is very nice. There is a computer, a bed, a lamp ,a wardrobe and a bookshelf above the table. The kitchen has a refrigerator, a stove and a sink,... Next to the kitchen is the bathroom. It has a shower, a washing machine and a tub. I love my house very much.  

 Chúc bạn học tốt!!!

My secondary school is a place that bears all the hallmarks of my childhood memories. It is placed in the center of my district. Surrounded by a paddy-field, it enjoys lined- trees and colorful garden, which creates a wonderful view. Moreover, this school was designed with a large- scale plan. It is a 2 storied building of u shape with capacity of 1000 people and it was invested heavily in infrastructures with well- equipped classrooms. In a good environment, students are given many precious chances to discover and develop their inner talents. Besides modern facilities, this school is also well- known for enthusias and qualified teachers who are always dedicated and devoted themselves to teaching career. In conclusion, studied in this school for four years, it has become an indispensable part in my life.
 

Tỉ lệ : 4:3:2

1E

2H

3F

4C

5B

6D

A=4/3(13/9-40/9)

A=4/3x-3

A=-4

25% của A là:-1

\(A=\frac{4}{3}.\frac{13}{9}-\frac{4}{3}.\frac{40}{9}\)

\(\Rightarrow A=\frac{4}{3}.\left(\frac{13}{9}-\frac{40}{9}\right)\)

\(\Rightarrow A=\frac{4}{3}.\frac{-27}{9}\)

\(\Rightarrow A=\frac{4}{3}.\left(-3\right)\)

\(\Rightarrow A=-4\)

25% của A là : 

\(-4:4=-1\)

Vậy 25% của A là -1 

Chúc bạn học tốt !!!