Câu 2. a. Tính hóa trị của Mg trong hợp chất MgCl2, biết Cl(I) b. Tính hóa trị của Al trong hợp chất Al2O3, biết O (II) Câu 3. a) Lập công thức hoá học của các hợp chất tạo bởi a. Mg (II) và O (II) b. Al (III) và nhóm SO4 (II) c. Na (I) và nhóm NO3(I) b) Tính phân tử khối của các hợp chất sau a. NaCl b. HNO3 c. Fe(OH)3

Các câu hỏi liên quan

III. Fill in each blank in the following letter with a suitable word. Dear Mary, Thanks for your letter. Now I’ll tell you (1) ...... my hobbies. My favourite hobby is knitting. It is strange, isn’t it? My mother (2) ....... me to knit two years ago. Now I can knit scarves and sweaters. It’s great when I can (3) ....... them to my relatives and friends as gifts. Knitting is also imaginative (4) ...... you can knit anything you can imagine of. Besides, it is quite cheap. You only need a pair of needles and some wool. I’m sending you a scarf next month. I’m knitting it. I (5)....... you’ll like it. IV. Rewrite the sentences, active or passive. 1. The store was opened in 1932 by Jack. Jack.................................................................................................................................. 2. Has anyone told you about it yet? Have you ......................................................................................................................... 3. Somebody accused him of stealing the money. He .................................................................................................................................... 4. People are going to build a bridge over my house. A bridge........................................................................................................................... 5. They built many buildings to commemorate Uncle Ho’s birthday. Many buildings ............................................................................................................... 6. They will ask us all several questions. We shall........................................................................................................................... 7. They must observe the rules of the games carefully. The rules.......................................................................................................................... 8. They were building a new stadium when I arrived. A new stadium ................................................................................................................ 9. Newspaper are sold everywhere in the city. People.............................................................................................................................. 10. Did the woman buy those vegetables? Were those vegetables.....................................................................................................