Đặt a,b là số mol Mg, R trong 8 gam A. Đặt x,y là hoá trị thấp cao của R

mA = 24a + bR = 8 (1)

Với HCl -> 2a + bx = 0,2 .2  (2)

Trong 9,6 gam A ( gấp 1,2 lần 8 gam A ) chứa 1,2a và 1,2b mol Mg, R

Với Cl2 -> 2 . 1,2a + 1,2by = 2 ( 30,9 - 9,6 ) / 71 (3)

Với 1  ≤ x ≤ y ≤ 3 -> Chọn x = 2; y = 3

(2)(3) -> a = b = 0,1

(1) -> R= 56 ->  = Fe

1. The manager told me to come into her office.

2. The teacher told us not to make so much noise.

3. Mr. Green told Bill to come to their dinner that night.

4. Susan told Tom not to call her again at that late hour.

5. She told the boy to show her what they had in their hand.

6. The policeman ordered me to stay where I was and not to touch anything.

7. The old lady told me to water those flowers for her.

8. She told me not to leave my coat on that chair.

9. She told him not to speak to her liked that and to behave myself.

10. Peter told me to lending him my dictionary till the following Monday.

1. He has written to me since April.

=> The last time he wrote to me was April.

2. She hasn’t had a swim for five years.

=>  She last had a swim 5 years ago

3. They last talked to each other two months ago.

=> They haven’t talked to each other for two months.

4. The last time she saw her elder sister was in 1999.

=>  She hasn’t seen her elder sister since 1999

5. She hasn’t written to me for years.

=>  It’s years since she last wrote to me

6. It’s two weeks since they deaned their room.

=>  They haven't cleaned their room for two weeks

7. How long is it since you rode a bicyde?

=>  When did you last ride a bicycle?

8. How long is it since he wrote to ỵou?

=>  When did he last write to you?

9. When did he last talk to you?

=>  How long is it since he talked to you?

10. When did you last telephone him?

=>  Hong long is it since you telephoned him?

11. We have never eaten this kind of food before.

=>  It’s the first time we have ever eaten this kind of food

12. This is the fìrst time I have seen this fìlm.

=>  I have never seen this film before

13. This is the first time he went abroad.

=>  He hasn’t gone abroad before.

14. She started driving 1 month ago.

=>  She has driven for 1 month

15. We began eating when it started to rain.

=>  We have eaten since it started to rain

16. I last had my hair cut when I left her.

=>  I haven’t  cut my hair since I left her

17. The last time she kissed me was 5 months ago.

=>  She hasn’t  kissed me for 5 months

18. It is a long time since we last met.

=>  We haven’t met for a long time

19. When did you have it ?

=>  How long have you had it ?

20. This is the first time I had such a delicious meal .

=>  I haven’t had such a delicious meal before

21. I haven’t seen him for 8 days.

=>  The last time I saw him was 8 days ago

22. I haven’t taken a bath since Monday.

=>  It is Monday since I last took a bath

23. It's 2 years since I had a punture.

=>  I have not had a punture

24. It's 2 months since he earned any money.

=>  He hasn't eared any money for 2 months

PHẦN A: NGỮ ÂM 

I. Chọn từ có phẩn gạch chân được phát âm khác với các từ còn lại.

Question 1.     A. house                B. horse                 C. hour                        D. hot

Question 2.     A. finished            B. opened              C. looked                        D. stopped

II. Chọn từ có trọng âm chính rơi vào vị trí khác với các từ còn lại.

Question 3.     A. again                B. teacher              C. happen                        D. table

Question 4.     A. lazy                  B. begin                C. boring                        D. student

PHẨN B: NGỮ PHÁP VÀ TỪ VỰNG 

I. Cho dạng đúng của động từ trong ngoặc để hoàn thành các câu sau.

Question 5. The children (clean)______are cleaning_______ the windows at the moment.

Question 6. He used to (smoke) _______ smoke______ 10 cigarettes a day.

Question 7. Our teacher asked us (prepare) _____ to prepre________ our lessons carefully.

Question 8. I (go) _______went______ to the restaurant with my brother yesterday.

Question 9. Look at those black clouds! It (rain) __ is going to rain___________.

Question 10. They (not finish) _____haven't finished_______ their homework yet.

Question 11. If the weather is fine, we (go) _____will go________ for a picnic.

Question 12. This house (build) ____was built_________ over 100 years ago.

II. Chọn một từ đúng trong ngoặc để hoàn thành các câu sau.

Question 13. Nam is a student ____his____ school is in the countryside. (He / His)

Question 14. She has been a teacher of English ____ since____ 2001. (since / for)

Question 15. Mai didn’t go to school yesterday ___because_____ she was ill. (because / although)

Question 16. My sister speaks English very ____fluently____. (fluent / fluently)

Question 17. Tet is the most important __celebration_____ in Vietnamese culture. (celebrate / celebration)

Question 18. What’s the name of the man _____who___ gave us a gift? (who / whom)

Question 19. You should write ___in_____ ink, not with your pencil. (in / by)

Question 20. I will play tennis tomorrow ___unless_____ I am busy. (unless / if)

a) 8,3 × 0,4 = 3,32

b) 4,2 × 1,5 = 6,3

c) 0,24 × 2,5 = 0,6

Thổi V lít khí CO2 (đktc) vào 100ml dung dịch Ca(OH)2 1M thu được 6 gam kết tủa X và dung dịch Y. Lọc toàn bộ kết tủa, sau đó đun nóng dung dịch Y lại thấy xuất hiện kết tủa nữa. Tìm V?

A. 1,12 lít.

B. 2,24 lít.

C. 3,136 lít.

D. 3,36 lít.

Thổi 7,84 lít khí CO2 (đktc) vào dung dịch Ca(OH)2 dư thu được kết tủa X và dung dịch Y. Lọc toàn bộ lượng kết tủa ra khỏi dung dịch, sau đó nung đến khối lượng không đổi thu được chất rắn Z có khối lượng m. Tìm m.

A. 19,6 gam.

B. 35 gam.

C. 56,7 gam.

D. 20 gam.

Hòa tan vừa hết 14,8 gam Ca(OH)2 cần V ml dung dịch HNO3 2 mol/l. Giá trị của V là

A. 100

B. 200

C. 300

D. 400