Mọi người làm giúp em bài 4 ạaaaaaaa

Cho 44,8 gam Sắt (Fe) tác dụng với dung dịch loãng có chứa 49 gam axit sunfuric (H2SO4), tạo ra khí hiđrô và sắt(II) sunfat

a). Viết phương trình hóa học xảy ra.

b). Tính thể tích khí H2 sinh ra (ở đkc)

c). Dẫn toàn bộ lượng khí hiđro thu được qua m gam CuO nung nóng. Tính m?

Câu 4: Hãy cho biết bình dưỡng khí (cung cấp oxi) được sử dụng trong tình huống nào?

B

A

It is very hot during summer. This causes people to sweat. Sweating is a great way to cool your body. Animals in the wild also sweat when they are hot. Most people and animals have colorless sweat. But one animal, the hippopotamus, (1)____ has a different kind of sweat: It’s red!  In the past, many people thought that hippos were sweating blood. (2)__________, scientists discovered that it is not blood. The red liquid is actually just sweat. It protects the hippo’s skin from the sun. It is like a sunscreen! The sweat of hippos also has another special purpose. The sweat has an important medicine in it. Hippos often fight and wound one another. The medicine (3)__________ the wounds. It also keeps away bad infections.

Hippos get hot and sweaty in summer, just like you! Their red-colored sweat looks very strange. However, it protects their skin and fights disease. The sweat of hippos helps them stay (4)__________ all summer!

1. A. who                                 B. why                                     C. where                      D. which

2. A. Therefore                                      B. Moreover                          C. Accordingly                        D. However

3. A. repairs                             B. mends                                 C. heals                                    D. fixes

4. A. healthy                            B. health                                  C. unhealthy                D. healthily