what  cái j

dang bội cơ

Trả lời :

- Cần trộn dd NaOH 3% và 10% với tỉ lệ khối lượng 2 : 5 để có dd NaOH 8%

~HT~

#NDH

Đáp án:

 2 : 5

Giải thích các bước giải:

 Gọi khối lượng dung dịch NaOH 3%, dung dịch NaOH 10% là m1, m2

Trong m1 g dd NaOH 3% có: mNaOH = m1 . 3% = 0,03.m1 (g)

Trong m2 g dd NaOH 10% có mNaOH = m2 . 10% = 0,1 . m2 (g)

Khi trộn 2 dung dịch trên với nhau thu được dung dịch có

       mdd = m1 + m2 (g)

       mNaOH = 0,03.m1 + 0,1.m2 (g)

Dung dịch thu được có C% = 8%

0,03.m1+0,1.m2:m1+m2.100%=8%

→0,02.m2=0,05.m1

→m1:m2=2/5

học tốt 

Giải thích rõ cho mik đc hok ah

Đây là Hóa hay Anh hả bạn ??????

In my daily life, I have several hobbies such as cooking, surfing, listening to music and so on. However, I reading books the most for some reasons. Firstly, reading makes me feel comfortable after many long stressful hours at school. I actually comic books because they contain lots of colorful and interesting images that keep my spirit relax. Secondly, reading books provides me a great deal of diverse knowledge of many fields. For instance, I can know more specific culture of each country in The World’s Cultures book. In addition, I can know more things about different life of various animals that are living around the world in the Discovery of Animals World book. Finally, reading helps to enhance my vocabulary in both Vietnamese and English language. In Vietnamese book, I can learn many traditional folks or proverbs that help me understand more deeply the beauty of my mother tongue. About English books, I can improve my English reading comprehension skill in study. Besides, my communication skill with the foreigners will be better, too. In conclusion, I really reading books, for it brings many good things to me. I see it as an useful activity to learn how to make life more meaningful and beautiful.

My hobby is fooball and games

1, who is the most intelligent person in your family ?
2, this stadium is the most morden in Europe
3.melanie is the kindest girl I have know
4. what is the happyiest day in your life?
5. this Beatles album is the best they ever made.
6. Asernal is the most popular team in England
7. This painting is the most valuable in the gallery.
8. What is the most important school subject?

học tốt

1.Who is the most intelligent person in your family ? 

2. This is the most modern stadium in Europe ? 

3. Melanie is the most kind girl I have known 

4. What is the happiest day in your life ?

5. This Beatles album is the best they have ever made

6. Asernal is the most popular team in England

7 This painting is the most valuable in the gallery

8. What is the most important school subject ? 

Đặt số hạt proton, notron, electron của nguyên tử nguyên tố R lần lượt là \(p,n,e\).

Ta có: 

\(\hept{\begin{cases}p+n+e=54\\p=n\\p=e\end{cases}}\Leftrightarrow\hept{\begin{cases}3p=54\\p=n=e\end{cases}}\Leftrightarrow p=n=e=18\).

Vậy số hạt proton, notron và electron của nguyên tử nguyên tố đã cho đều là \(18\).

Gọi N;P;E là số n;p;e có trong X

Theo gt:N+P+E=49

vì số p=số e nên:2P+N=49(1)

Mặt khác:số hạt không mang điện bằng 53,125% số hạt mang điện nên:

N=53,125%(P+E)

=>N=1,0625P(2)

Thay (2) vào (1) ta có:

3,0625P=49=>P=E=49:3,0625=16

=>N=49-2P=49-16.2=17

Vậy X là S(lưu huỳnh)

nhớ t i k đó

học tốt

1.25.1u 4:1 là j vậy bạn mình ko hiểu

H2+2O+H2O  nhé bn Hk tốt:)

Can you tell me how to get to the stadium?

can/tell/how/stadium?

=> Can you tell me how to get to the stadium?

Học tốt

Đọc sai : Canxi (II) oxit => Canxi Oxit Vì Canxi và Oxi có cùng hóa trị II

               Lưu Huỳnh (IV) oxit => Lưu Huỳnh Đioxit

               Đinatri oxit => Natri Oxit