Bài 4 : Hoàn thành các phản ứng hóa học sau ( ghi rõ điều kiện phản ứng nếu có): 1) Na + O2 → ? 2) CH4 + O2 → ? + ? 3) Al + O2 → ? Bài 5: Khi đốt sắt ở nhiệt độ cao thu được oxit sắt từ (Fe3O4) a) Tính khối lượng sắt cần thiết để điều chế được 4.64g Fe3O4 b) Tính thể tích O2 tham gia (ở đktc ) c) Tính thể tích không khí cần dùng ( biết thể tích oxi chiếm 1/5 thể tích không khí )

Các câu hỏi liên quan

III. Read the following text and use the words given in the box to fill the blanks. There are 2 extra words you don’t need to use. Travelers; more; country; among; of; islands; foreigners The unique beauty of Ha Long bay with its karst makes it a natural to be added to UNESCO’s World heritage listing. But, it seems the opinions are divided (1)________________ travelers. There are (2) _________________ than1, 600 islets in the bay, their limestone worn down by 500 million years of tropical downpours, and topped by thick jungle growth. Some of the islands are hollow, creating majestic caves. Some of the larger (3) _____________ have their own lakes. At the centre (4) _____________ the bay there are 775 of the formations in an area of just 330 square kilometres - an invitation for (5) ______________ to board a traditional Vietnamese junk-boat and explore the bay, it’s island, caves, and floating villages. WRITING I. Finish each of the following sentences so that its meaning stays the same. 1. The last time we saw her was on Christmas day. -> We haven’t _____________________________________________________ 2. I haven’t eaten this kind of food before. -> This is _________________________________________________________ 3. It started raining an hour ago. -> It has __________________________________________________________ 4. We haven’t visited our grandfather for two months. -> The last time _________________________________________ 5. I have studied English for three years. -> I began ________________________________________________________ 6. My brother hasn’t been his best friend for nearly five years. -> It’s __________________________________________________________