có ai biết làm k giúp với
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30 tháng 7 2021
PTHH: \(SO_2+2KOH\rightarrow K_2SO_3+H_2O\)
Ta có: \(n_{SO_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\) \(\Rightarrow n_{KOH}=0,1\left(mol\right)\)
\(\Rightarrow C_{M_{KOH}}=\dfrac{0,1}{0,1}=1\left(M\right)\)
30 tháng 7 2021
có ai biết giải bài này k mình đang cần rất gấp mong các bạn giúp cho
Bài 1: cho 5,6g oxit của kim loại hóa trị (II) vào nước thu đc 200g dd bazo với nồng độ 3,7%. hãy xác định công thức của oxit trên.
TC
28 tháng 7 2021
IV. Rewrite these sentences
This room is bigger than that one
Þ That room is not as big as this one.
Þ That room is smaller than this one
2. Linda drives faster than Peter
Þ Peter doesn't drive as fast as Linda.
Þ Peter drives slower than Linda.
3.Your car is more expensive than mine
Þ My car is cheaper than yours.
Þ My car is not as expensive as yours.
Þ My car is less expensive than yours
4. I play football better than my brother
Þ My brother plays football worse than me.
Þ My brother dosen't play football as well as me.
5. We can cook worse than him
Þ He cooks better than us.
Þ He doesn't cook as badly as us.
6. Anna isn’t as slim as me
=> I am slimmer than Anna.
7. This book isn’t as good as that one
Þ That one is better than this book.
8. I don’t work as dangerously as he does
=> He works more dangerously than I do.
9. My bedroom isn’t so nice as yours
Þ Your bedroom is nicer than me.
10. John didn’t speak English as fluently as Mary
=> Mary spoke English more fluently than John.
11. I can swim farther than my brother
=> My brother can’t swim as far as me.
12. Jack studies worse than Peter
=> Peter studies better than Jack.
=> Peter doesn't study as badly as Jack.
13. Cats can’t swim as well as dogs can
Dogs can swim better than cats .
14. She drives more carelessly than me
=> I drives more carefully than she.
=>I don't drive as careless as she.
V.Cho dạng so sánh hơn hoặc so sánh nhất cùa các tính từ trong ngoặc để hoàn thành các câu sau:
1. Josh is the second (intelligent) _____most inteligent_______________ student in his class.
2. If only the traffic in my hometown was (convenient) more convenient than it is now.
3.Hanoi is amongst (polluted) the most polluted city in the world.
4. I wish that my house was (spacious) ______more spacious__.
5.By far, this is (stunning) _the most stunning__ scene I have ever seen.
6. He seems to be (tall) __the tallest____ amongst the children at his age.
7. You did a quite good job yesterday but I expected you to be (good) _____better______________. You got me down a little bit.
8. This must be (inspiring) the most inspiring speech of yours. Everyone in the room clapped their hands in delight.
9. Admittedly, I anticipated a (good) less better performance of yours. You didn’t prepare well for this, did you?
10. This is not (expensive) the most expensive car in the showroom. There are many other cars at higher cost.
VI.Nâng cao
Viết lại câu sau sao cho nghĩa không thay đổi, sử dụng dạng so sánh hơn của trạng từ hoặc tính từ.
0. Living in the city is much more expensive than living in the countryside.
ð Living in the countryside is much cheaper than living in the city.
1. My current house is more spacious than the old one.
ð My old house is less spacious than my current one.
2. He performed better than he was expected.
ð He was expected his performance less better than he did.
3. This time Mice run faster than his brother.
ð This time Mike’s brother runs slower than he
4. I think you will have a higher position in our company than Jim.
ð I think Jim will not have a higher position in our company than you.
5. Jane decorated her cake more beautifully than I did.
ð I didn't decorate my cake as beautifully as Jane did.
6. This year Peter invested a larger amount of money on his business than last year.
ð Last year Peter didn't invest as large amount of money on his business as this year.
7. My computer is costlier than Jim’s.
ð Jim’s computer is not costly as mine.
8. Playing sports is more time-saving than playing computer games.
ð Playing computer games is less time-saving than Playing sports.
DT
11 tháng 8 2021
V. Sử dụng thì hiện tại đơn hoặc thì hiện tại tiếp diễn trong những câu sau
1. She ................plays........................ (play) tennis every Sundays.
2. The students (not, be).........aren't................in class at present.
3. The children (play)...................are playing........ in the park at the moment.
4. He ............................buys............ (buy) a cup of coffee every morning.
5. Julie ...........................comes............. (come) from Russia .
6. Jack and Peter (work) ____work____ late today.
7. Luke ...........................usually studies............. (usually /study) hard to be polite.
8. She ...............................enjoys......... (enjoy) going swimming twice a week.
9. The weather (get) __gets______ cold this season.
10. My children (be)___are__ upstairs now. They (play)_are playing_____ games.
11. Lucy ......................washes.................. (wash) her hair every day
12. John never ........cries................................ (cry).
13. My mother always .............says........................... (say) that love is more important than money.
14. Julie .....passes................................... (pass) the exam once a year.
15. The sun .................rises....................... (rise) in the East.
..................................................
DT
8 tháng 8 2021
II. Rewrite these sentences
1. This street is narrower than that one
Þ That street …isn't as narrow as this one…………………………………………..
Þ That street …is bigger than this one………………………………………………
2. Linda drives more carefully than Peter
Þ Peter……doesn't drive as carefully as Linda………………………………………
Þ Peter…drives more carelessly than Linda………………………………………………..
3.Your car is more convenient than mine
Þ My car ……isn't as convenient as.yours………………………………………………..
Þ My car……is incovenient than yours………………………………………………..
4. We behave more politely than her
Þ She………behaves less politely than us……………………………………………….
Þ She ………doesn't behave as politely as us………………………………………………
5.I cook better than my mother
Þ my mother………doesn't cook as well as me……………………………………………………..
Þ my mother ………cook more badly than me………………………………………………………
6. Anna isn’t as confident as me
=> I …am more confident than Anna………………………………….
7. This book isn’t as boring as that one
Þ That book ….....is more boring than this one...................................................
8. I don’t work as effectively as he does
=> He ………work more effectively than me………………………………….
9. My bedroom isn’t so comfortable as yours
Þ Your bedroom……is more comfortable than mine………………………..
10. John didn’t speak English as well as Mary
=> Mary ………spoke English better than John………………………………….
11. Peter can dance the most gracefully in my city
=> No one……can dance as gracefully as Peter in my city
…………………………………………….
=> No one………can dance more gracefully than ………………………………………
12. Kangaroo is the most unique animal in the world
=> No………animal in the world is more unique than Kangaroo……………………………………………..
=> No…………animal in the world is as unique as kangaroo…………………………………………….
13. No river in the world is longer than Nile
=> Nile ……is the longest river in the world……………………………………………
14. No student in my class learns Maths more intelligently than John
=> John………learns Math the most intelligently in my class ……………………………………………………………
15. If you read many books, you will have much knowledge
→ The more …books you read, the more knowledge you have………………………………………………………………….
16. He speaks too much and people feel bored.
→ The more …he speaks, the more bored people feel………………………………………………………………….
III. Cirle the best option to complete each sentence:
1. The flower was.......... out of a single piece of valuable wood.
A. carved B. moulded
C cast D. given
2. In this town, they_____ all the frames in steel.
A. make B. have C. mould D. cast
3. She is skilled at ____ cloth.
A. giving B. weaving C doing D. carving
4. If you like, I can_____ flowers on the cushion covers for you.
A. grow B. make C. embroider D. knit
5. Is it true that you.......... this woollen hat yourself?
A. knitted B. wove C did D. carved
6. The doll has been.......... out of clay.
A. embroidered B. cast C. woven D. moulded
7. I love going to this place _____ it's the quietest place in the city.
A. so B. though C. so that D. as
8. They keep changing the decoration of the shop_______ they can attract more young people.
A. so that B. because C. although D when
9.________ he's young, she's the most famous artisan in the village.
A. When B. Although C. Whereas D. In order to
10. Do you know who's______ his pottery workshop?
A. bring out B. taking over C. passing down D. turning down
11. I've_______ the product catalogue and decided to buy this table.
A. found out B. closed down C. looked through D. lived on
12. This sports centre is so small that it cannot______the demands of local residents.
A. keep up with B. face up to C. deal about D. setup
13. When I turned up, the town hall was already_____ of teenagers.
A. full B. packed C. crowded D. jammed
14. She turned ______the new job in New York because she didn't want to move.
A. on B. down C. off D. up
15. This city has one of the most___ underground rail networks in the world.
A. efficient B. fashionable C . cosmopolitan D. fascinated
16. This laptop is much more user-friendly, but it costs________ the other one.
A. so much as B. as many as C. twice as much as D. twice as many
17. Today's cities are____than cities in previous times.
A. lots larger B. much larger C. as large D. the largest
18. After I found all the information I needed, I________the computer.
A. turned off B. switched on C. looked for D. put off
19. Japan is the__________ developed country in the world.
A. most second B. second in most C. second most D. two most
20. Factories and offices should be built in __________areas only.
A. rural B. Coastal C. culture D. urban
21. My grandfather is _____ the oldest person in my village
A. by far B. a lot C. second D. much
22. The last runner tried ____ better than the first one
A. by far B. third C. a bit C, more
NL
1
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
8 tháng 6 2023
2. So sánh: A = \(\dfrac{1}{41}\) + \(\dfrac{1}{42}\) + \(\dfrac{1}{43}\) + \(\dfrac{1}{44}\)+...+ \(\dfrac{1}{80}\) và B = \(\dfrac{7}{12}\)
\(\dfrac{1}{41}>\dfrac{1}{42}>\dfrac{1}{43}>...>\dfrac{1}{60}\)
Xét mẫu số các phân số trên lần lượt là các số thuộc dãy số sau:
41; 42; 43;...;60
Dãy số trên là dãy số cách đều với khoảng cách là: 42 - 41 =1
Số số hạng của dãy số trên là: (60 - 41):1 + 1 = 20
⇒ \(\dfrac{1}{41}\) + \(\dfrac{1}{42}\)+...+ \(\dfrac{1}{60}\) > \(\dfrac{1}{60}\) \(\times\) 20 = \(\dfrac{1}{3}\) (1)
Chứng minh tương tự ta cũng có:
\(\dfrac{1}{61}+\dfrac{1}{62}+...+\dfrac{1}{80}\) > \(\dfrac{1}{80}\) \(\times\) 20 = \(\dfrac{1}{4}\) (2)
Kết hợp(1) và (2) ta có:
A = \(\dfrac{1}{41}+\dfrac{1}{42}+\dfrac{1}{43}+\dfrac{1}{44}+...+\dfrac{1}{80}\) > \(\dfrac{1}{3}\) + \(\dfrac{1}{4}\) = \(\dfrac{7}{12}\)
Vậy A > B
a: Xét ΔABE và ΔACD có
AB=AC
\(\widehat{BAE}\) chung
AE=AD
Do đó: ΔABE=ΔACD
=>BE=CD
b: ΔABE=ΔACD
=>\(\widehat{ABE}=\widehat{ACD}\) và \(\widehat{AEB}=\widehat{ADC}\)
\(\widehat{AEB}+\widehat{BEC}=180^0\)(hai góc kề bù)
\(\widehat{ADC}+\widehat{BDC}=180^0\)(hai góc kề bù)
mà \(\widehat{AEB}=\widehat{ADC}\)
nên \(\widehat{BEC}=\widehat{BDC}\)
=>\(\widehat{OEC}=\widehat{ODB}\)
AD+DB=AB
AE+EC=AC
mà AD=AE và BA=AC
nên DB=EC
Xét ΔODB và ΔOEC có
\(\widehat{ODB}=\widehat{OEC}\)
DB=EC
\(\widehat{OBD}=\widehat{OCE}\)
Do đó: ΔODB=ΔOEC