Viết công thức hóa học và tính phân tử khối của các hợp chất sau: a) Natri nitrat có phân tử gồm 1Na, 1N và 3O liên kết với nhau. b) Benzen có phân tử gồm 6C và 6H liên kết với nhau. c) Oxit sắt từ có phân tử gồm 3Fe và 4O liên kết với nhau.

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MY HOME TOWN I was born in Newcastle, a city in the North East of England. Newcastle is on the bank of the River Tyne. It is a quite big city of about 200,000 inhabitants. There is a cathedral and a university. There are five bridges over the River Tyne, which link Newcastle to the next town, Gateshead, where there is one of the biggest shopping centres in the world, the Metro Centre. , A few years ago, the main industries were shipbuilding and coalmining, but now the chemical and soap industries are important. I moved from Newcastle ten years ago but I often return. I miss the people, who are so warm and friendly, and I miss the wild, beautiful countryside near the city, where there are so many hills and streams. 39. Newcastle is ___________________ . a. a city near the North East of England b. a city in the North East of England c. a city in the North of England d. a small town in England 40. Newcastle has________________________ . a. one of the biggest shopping centers b. a wild, beautiful countryside c. a population of about 200,000 people d. one bridge that links it to the next town 41. Gateshead has one of_______________ in the world. a. the largest rivers b. the most important shipbuilding industries c. the most beautiful countrysides d. the biggest shopping centres 42. According to the passage, the writer_____________ . a. is still living in Newcastle b. has never returned to Newcastle c. doesn’t live in Newcastle any more d. has come back to live in Newcastle 43. Which of the following is NOT true about Newcastle? a. Its people is friendly. b. Its main industry now is shipbuilding, c. It has a cathedral and a university, d. It is next to Gateshead