Tìm nghiệm nguyên x,y biết 2^x+1=y^2 nhờ Mn giúp

Câu 3: Cho 5,4 gam bột nhôm tác dụng vừa đủ với 400ml dung dịch HCl a. Viết phương trình hóa học xảy ra b. Tính nồng độ mol/lit của dung dịch HCl đã dùng Giải: a.. PTHH: 2Al + 6HCl →2AlCl3 + 3H2 b. Đổi 400ml = 0,4l Theo PTHH : 2Al + 6HCl → 2AlCl3 + 3H2 (mol) 2 6 2 3 (mol) 0,2 0,6 0,2 0,3 nHCl = 0,6 (mol) Hỏi các bạn: Giải thích hộ là Tại sao không tính nHCl=0.4/22.4 mà phải lấy theo nAl=3nAl=0.6(mol) Cảm ơn!

Dung dịch A chứa CH3COOH 0.1M và HCOOH x(M). Xác định x để hh này có pH=2,72. Biết K(HCOOH)=1,8×10^-4; K(ch3cooh)=1,8 ×10^-5 Giúp em với ạ

Giúp e cậu b bài 2 ạ! K vẽ hình nha MN!

TRƯỜNG TIỂU HỌC …………………………… KIỂM TRA CUỐI HỌC KỲ II NĂM HỌC 2019-2020 MÔN TIẾNG ANH- LỚP 5 Thời gian: phút PART B. READING AND WRITING Task 1. Read and Circle the odd one out. 1.a.tooth b.cough c.cold d.headache 2.a.singer b.player c.sister d.farmer 3.a.you b.my c.him c.her 4.a.played b.went c.get d.were Task 2 . Read and match. 1. Can we go to the museum? a. I’d like some rice, please. 2. What would you like? b. Mount Everest. 3. What’s the highest mountain in the world? c. I don’t like museums. 4. Do you have English and Math on Monday? d. Yes, I do. 5. Is this a beautiful park? e. Yes, it is. Task 3: Read and circle the correct answer. 1. Are you going to do your homework? - Yes,............ A. I am B. I was C. he is D. he was 2. What's the matter............. you? -I have a cold. A. to B. with C. from D. in 3. How many seasons are............ in England? A. these B. those C. they D. there 4. It's often............... in the rainy season. A. cold B. warm C. rainy D. Sunny Task 4: Read the passage and write T( true )or F (false). Linda is from England. There are four seasons in her country. In summer, it is hot. She often goes swimming. In autumn, it is cool and wet. Her father and she sometimes go fishing. It is very cold in winter. They usually go skiing in the mountains. In spring, it is warm and beautiful. They often go camping in the national park. 1. Linda isn’t from England. 2. There are five seasons in her country. 3. Her father and she sometimes go fishing. 4. They usually go skiing in the mountains. 5. In spring, it is cool and beautiful. Task 5. Read and fill each gap with one word from the box. Write the word next to the number. There is one word that you do not need. There is one example (0). Can Tho is a big (0) city in the South of Viet Nam. People often go there by coach or by (1) ___________. Can Tho Bridge is a beautiful place to look down the wide and long (2) _________ and the landscape on the banks. There are beautiful floating (3) ___________on the rivers in Can Tho. People sell fruits, vegetables, meat or fish from their (4) __________. Can Tho is a beautiful city, and the weather is always (5) ___________. In the rainy season, it can be quite wet. Task 6: Put the words in order. 1.today / These / going / the / students / are / cinema / to. ______________________________________________________________________ 2.stay / home / you / yesterday / at / Did /? ______________________________________________________________________ 3.go / your / does / Where / weekend / brother / on / ? ______________________________________________________________________ 4.like / the / in / What / weather / summer / is ? _____________________________________________________________________

cho a<b, chứng minh 4-2a>4-2b

Giúp mình bài này với ak, hơi nhìu :))))

giúp mình giải câu 36 vs cách tọa độ hóa .thanks mn

Câu 1:so sánh hai phân số sau A)3/5 và 2/5 B)1/5 và 1/7 C)-3/4 và 2/5 D)-5/7 và -3/14 E)102/97 và 99/101 F)-5/14 và -4/11 Bài 2:quy đồng mẫu số rồi sắp xếp các phân số sau theo thứ tự tăng dần:3/-8;-7/12;2/3;5/6 Giúp mk vs nha mk cảm ơn nhiều

" Loudness, a subjective measure, is often confused with physical measures of sound strength such as sound pressure, 'sound pressure level' (in 'decibels'), 'sound intensity' or 'sound power' " nghĩa là gì?