Hòa tan hết 17,4 gam hỗn hợp X gồm FeO, Fe(NO₃)₂ và Mg vào dung dịch chứa 0,39 mol H₂SO₄ loãng. Sau phản ứng thu dược dung dịch Y chỉ chứa 50,24 gam muối sunfat và 0,07 mol hỗn hợp khí Z gồm 2 khí không màu, trong đó có một khí màu nâu ngoài không khí có tỉ khối hơi so với H₂ bằng 5. Tính phần trăm khối lượng của Mg trong hỗn hợp X.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 33 to 37. Fill in the appropriate word in question 34

Some years ago, my daughter was studying English at a university on the south coast. One evening she phoned to tell me that what she really wanted to do was looking (33) _____ the world, so she was looking into the possibility of working in another country. She had seen several (34) _____ in the newspaper for student teachers of English abroad, and she was interested in one in Italy, which she was desperate to visit. She decided that this would be a good way to achieve her ambition, so she was writing to apply for the job. The reply took a long time to arrive, but eventually she received a letter asking if she would go for an interview in London the following week. She was so excited that she immediately got in touch with the school owner and agreed to attend the interview. She was determined that nothing would prevent her (35) _____ doing what she had set out to do. A few days before the interview she had a very strange dream in which she gave birth to a beautiful baby. She was a little nervous and (36) _____ about the dream and phoned to ask me what I thought it might mean. As I knew something about dreams, I was able to assure her that it only symbolized her (37) _____ to do well in the interview. 

A. posters

B. notices

C. advertisements

D. announcements

Khi clo hóa một ankan có công thức phân tử C₆H₁₄, người ta chỉ thu được 2 sản phẩm thế monoclo. Danh pháp IUPAC của ankan đó là

A. n-hexan

B. 2,3-đimetylbutan

C. 2,2-đimetylbutan

D. 2-metylpentan