Viết khối lượng phân tử, tên nguyên tố và công thức hóa học

a) 1 C + 2 O

b) 2 H + 1 O

c) 1 N + 3 H

d) 1 C + 4 H

e) 2 H + 1 S + 4 O

Khối lượng nguyên tử: H = 1, S = 32, O = 16, C = 12, N = 14

Hãy tính hóa trị của:

1. Fe trong Fe²O³

2. Al trong Al(OH)³

3. N trong NH³

4. C trong CO²

5. H trong H²SO⁴

6. S trong SCl

7. Si trong SiO²

8. S trong SO²

9. C trong CH⁴

10. H trong H²O

Which sentence can we omit the relative pronoun?

1. Nikola Tesla is an inventor who invented electricity.

2. This is a place where I can collect some diamond and emerald ore.

3. I was at the primary school when I was six years old.

4. She was the person who is very beautiful.

5. Your option is an option that makes no sense.

6. This is where I can get a lot of money.

7. This is a thing which is very rare.

8. I started to ride a bike when I was five years old.

These people, fruits, strange birds have just 1 name. What is that?

Argh!

Please!

...

Ủa đúng mà, có 4 mà.

That's not hello! That's hell0!

Please...