có ai biết làm k giúp với
K
Khách
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30 tháng 7 2021
PTHH: \(SO_2+2KOH\rightarrow K_2SO_3+H_2O\)
Ta có: \(n_{SO_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\) \(\Rightarrow n_{KOH}=0,1\left(mol\right)\)
\(\Rightarrow C_{M_{KOH}}=\dfrac{0,1}{0,1}=1\left(M\right)\)
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
Đỗ Thanh Hải
CTVVIP
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.
..................................................
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