Phản hồi đến em!

1. The last time she went out with him was 5 years ago.

2. This is the first time we have seen such a cruel mother.

3. We haven't seen Mr.Johns for 2 years.

4. I haven't visited the USA before.

5. I began learning English 10 years ago.

6. The last time the Pikes visited Paris was 2 years ago.

7. I haven't written to him for a week.

8. It's been (=has been) 6 years since Mary started learning French.

9. My uncle started working in that factory 10 years ago.

10. My old friend has worked on that farm since 2005.

11. It's been a long time since my mother started having this machine.

12. My father hasn't drank champagne for 10 years.

12. We last saw Mary when we were in the university.

14. I haven't gone swimming  since I was in Spain.

15. She has moved to London for 20 years.

16. I haven't seen John sice he was leaving for Edinburgh.

17. The last time I saw her was 3 years ago. / It's 3 years since I last saw her.

gửi ảnh dọc đi ạ chứ ảnh ngang khó nhìn lắm

bạn đăng tách ra tầm 10 câu mỗi lần đăng nha, chứ dài ntnay ngại làm lắm~

Bảo toàn nguyên tố O :

 \(n_{H_2O\left(TN1\right)}=n_{H_2O\left(TN2\right)}=0.08\left(mol\right)\)

Ở TN2, Bảo toàn nguyên tố H : 

\(n_H=2\cdot n_{H_2O}=2\cdot0.08=0.16\left(mol\right)\)

Với cùng nồng độ mol thì : tỉ lệ số mol giữa HCl và H₂SO₄ : \(\dfrac{1}{0.5}=\dfrac{2}{1}\)

\(n_{HCl}=2a\left(mol\right),n_{H_2SO_4}=a\left(mol\right)\)

\(\Rightarrow n_H=2a+a\cdot2=0.16\left(mol\right)\)

\(\Rightarrow a=0.04\)

\(m_{Muối}=m_X+m_{HCl}+m_{H_2SO_4}-m_{H_2O}=5+0.08\cdot36.5+0.04\cdot98-0.08\cdot18=10.4\left(g\right)\)