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Kali có nguyên tử khối là 39 và hóa trị là I. 

8 tháng 11 2021

nguyên tử khối là 39

hóa trị I

1. Although Titanic is a …………………………..film, it has a sad ending. (ROMANCE)2. His recent film received a lot of ………………………….. from the public. (CRITIC)3. I don’t like horror films because they are too …………………………..for me. (FRIGHT)4. Do you know Daniel Day-Lewis? He has won three Oscars for Best…………………………… (ACT)5. The film was …………………………..though they spent millions of dollars making it....
Đọc tiếp

1. Although Titanic is a …………………………..film, it has a sad ending. (ROMANCE)


2. His recent film received a lot of ………………………….. from the public. (CRITIC)


3. I don’t like horror films because they are too …………………………..for me. (FRIGHT)


4. Do you know Daniel Day-Lewis? He has won three Oscars for Best…………………………… (ACT)


5. The film was …………………………..though they spent millions of dollars making it. (SUCCEED)


6. Big Ben Down is about a group of …………………………..who take control of Big Ben. (TERROR)


7. We were …………………………..with the service at the cinema. Everything was terrible. (SATISFY)


8. The film is a big…………………………… It is boring from beginning to end. (DISAPPOINT)


9. The film is about two hijackers who …………………………..to blow up the plane. (THREAT)


10. I don’t think it is good for young kids to see …………………………..on TV. (VIOLENT)

 

 

1
8 tháng 11 2021

1. roman 2. criism 3. frightening 4. actor 5. unsuccessful 6. terrorists 7. dissatisfied 8. disappointment 9. threatened 10. violence 

chúc học tốt 

1.Choose the best answer:1. She is____________old____________climb the mountain.A. very/ to B. enough/ to C. too/ to D. so/ to2. It is not_____________to pass the red traffic light.A. dangerous B. safe C. safety D. danger3. There are many_____________on the street: cars, buses, bikes, motorbikes…A. vehicles B. transport C. engines D. machines4. She spent all day_____________with her children.A. play B. to play C. played D. playing5. The central square is______________. It is full of people...
Đọc tiếp

1.Choose the best answer:

1. She is____________old____________climb the mountain.

A. very/ to B. enough/ to C. too/ to D. so/ to

2. It is not_____________to pass the red traffic light.

A. dangerous B. safe C. safety D. danger

3. There are many_____________on the street: cars, buses, bikes, motorbikes…

A. vehicles B. transport C. engines D. machines

4. She spent all day_____________with her children.

A. play B. to play C. played D. playing

5. The central square is______________. It is full of people and noise.

A. quiet B. peaceful C. crowded D. calm

6. Your behaviour is_______________. You should not be rude.

A. disappointing B. disappointed C. disappoint D. disappoints

7. If we walk, we should go on the___________.

A. street B. pavement C. traffic light D. road

8. “One-way street”, “No parking” are___________.

A. road signs B. means of transport C. traffic rules D. mistakes

9. He sings___________. Nobody wants to listen to his voice.

A. bad B. badly C. well D. good

10. He runs___________than me.

A. more faster B. more fastly C. more fast D. faster

2.Fill in each gap with one suitable word:

I live (1)____________Hanoi. It is (2)___________busy city. The streets (3)___________crowded and there are traffic jams in the rush hour. I am sometimes late for school because of the traffic jams. Some people don’t (4)___________the traffic rules. They pass the red traffic light, wear no helmets…Therefore, sometimes there (5)__________accidents. 

Word form:

1. The children were_____________by the stories about ghosts.( FRIGHTEN)

2. It is____________to use gun without permission. (LEGAL)

3. Be____________! A car is coming! (CARE)

4. Have you got______________license? (DRIVE)

5. Stop in front of the zebra______________when the traffic light turns into red.( CROSS)

3.Put question for the underlined part of each sentence:

1. It is 10 kilometers from here to ACB bank.

_______________________________________________________________________________________

2. I have known Marie for nine years.

_______________________________________________________________________________________

3. Yes, they used to be friends at the university.

_______________________________________________________________________________________

4. Sarah left two hours ago.

_______________________________________________________________________________________

5. She is watching Tom and Jerry.

_________________________________________________________________________________

1. A. wished                   B. gripped          C. loved      D. liked

 

2. A. excited B. enjoyed C. bored D. amazed

 

3. A. laughed B. ended C. shocked D. missed

 

4. A. advertised B. murdered C. performed D. approached

 

5. A. produced B. terrified C. entertained D. engaged

6
7 tháng 11 2021

1 .Choose the best answer

1. C

2. B

3. A

4. D

5. C

6. B

7. B

8. A

9. B

10. D

HT ( sai thông cảm )

7 tháng 11 2021

hóa học 7?????? lớp 7 làm gì có Hóa học

7 tháng 11 2021

1.B. enjoys

2.C. bought

3.B. sang

4.D. on

5.A. competition

Minh’s hobby is singing. She (1) ……… singing very much. When her brother (2) ……… a karaoke set last month, Minh was so glad that she (3) ……… every day after dinner. She s to sing only English songs. In fact, she has already sung all the songs found (4) ……… the karaoke discs. Minh is singing in the karaoke (5) ………… organized by the RC Center this Saturday. Her family is going there to support her.

1. A. wants B. enjoys C. thinks D. hates

2. A. invented B. discovered C. bought D. made

3. A. sings B. sang C. sung D. singing

4. A. of B. about C. under D. on

5. A. competition B. battle C. company D. institutio

13 tháng 2 2022

Hợp chất của R với H là RH

Vậy hoá trị thấp nhất của R là I và hoá trị cao nhất của R là \(VIII-I=VII\)

Vậy CTHH Oxit cao nhất của R là \(R_2O_7\)

Ta có \(\%R=38,80\%\)

\(\rightarrow\%R=\frac{2M_R}{2M_R+7.16}=38,80\%\)

\(\rightarrow2M_R=0,388.\left(3M_R+112\right)\)

\(\rightarrow2M_R=0,776.M_R+43,456\)

\(\rightarrow1,224M_R=43,456\)

\(\rightarrow M_R\approx35,5\)

7 tháng 11 2021

cần trợ giúp

14 tháng 11 2021

Gọi số protron ,notron ,electron trong a2b là pa ,na ,ea, pb, nb,eb  ( p,n,e ≠ 0 )

Tổng số hạt mang điện trong hạt nhân nguyên tử của hạt nhân là 54 : pa + p = 54   (1)

Số hạt mang điện trong nguyên tử a gấp 1,1875 lần số hạt mang diện tích trong nguyên tử b : 

2pa -  1.1875 x 2 x pb= 0   (2)    ( pa = ea ; p= eb )  

Từ (1) và (2) ta có phương trình  

pa + pb = 54                                 =>     p= 29

2pa -  1,1875 x 2 x pb =0                       pb = 24

CTHH của a2b là : Cu2Cr

7 tháng 11 2021

khí bạn thở ra

I. Using the word given and other words, complete the second sentence.1.I find collecting glass bottles interesting.                                                                    (HOBBY).2. Van’s brother usually goes to work by motorbike.                                                                                            (RIDES).3. What hobby do you like best, Elina?                                                                                                               ...
Đọc tiếp

I. Using the word given and other words, complete the second sentence.

1.I find collecting glass bottles interesting.

 

                                                                   (HOBBY)

.

2. Van’s brother usually goes to work by motorbike.         

 

                                                                                  (RIDES)

.

3. What hobby do you like best, Elina?   

                         

                                                                                     (FAVOURITE)

.

4. Linh finds playing board games boring.   

                     

                                                                                         (LIKE)

.

5. My sister enjoys arranging flowers. 

                           

                                                                                                   (FINDS)

0
8 tháng 11 2021

D. Sodium (Na) nha bn

12 tháng 11 2021

\(M+96=120\rightarrow M=24\rightarrow M\) là \(Mg\)

Vậy ta chọn đáp án A.

8 tháng 11 2021

nC=0,2, nH =(2,7-2,4)/1=0.,3 => CT chung (c2h3)n = 18x3 =>n=2 => A là C4H6