\(n_{C_2H_5OH}=\dfrac{2,76}{46}=0,06mol\)

C₂H₅OH+O₂\(\rightarrow\)CH₃CHO, CH₃COOH

CH₃CHO+Ag₂O\(\rightarrow\)2Ag

\(n_{CH_3CHO}=\dfrac{1}{2}n_{Ag}=\dfrac{1}{2}.\dfrac{3,024}{108}=0,014mol\)

CH₃COOH+NaOH\(\rightarrow\)CH₃COONa+H₂O

\(n_{CH_3COOH}=n_{NaOH}=0,01mol\)

-Tổng số mol C₂H₅OH bị chuyển thành anđehit và axit=2.(0,014+0,01)=0,048mol

%C₂H₅OH(pu)=\(\dfrac{0,048.100}{0,06}=80\%\)

C. b52 nha

# Hạnh ^^

ra C nha

tick cho mik nha

c

A) 243 : 3³ = 3⁵ : 3³ = 3²

B) 7⁶ : 49 = 7⁶ : 7² = 7⁴

C) b²² : b⁵ = b¹⁷

a, 243:3^3= 3^5 : 3^3 =3^2

b, 7^6 : 49 = 7^6 : 7^2 = 7^4

c, b^22 : b^5 = b^17

z 2 = a + bi 2 = a 2 - b 2  + 2abi

z 2 = a - b i 2 = a 2 - b 2  − 2abi

z. z  = (a + bi)(a − bi) = a 2 + b 2

Từ đó suy ra các kết quả.

Ta có:

A= 1/1.3 + 1/3.5 + .....+ 1/5.7 +......+ 1/19.21

2.A = 2/1.3 + 2/3.5 + 2/5.7 +...+ 2/19.21

2.A=  1- 1/3+ 1/3- 1/5+ 1/5- 1/7+............+ 1/19 - 1/21

2.A= 1- 1/21

2.A = 20/21

A= 20/21 : 2

A = 10/21

=> D

=>A mk nhầm

xl nhé hnay nt hiều quá 100 lần r lên k nt đc rất xl

Đăng lại vì ko ai giải 🥺

thôi bọn mềnh cũng chệu boạn nhóe

Ơ, đề đou bn?

* Tác hại của nó chính là: Những biểu hiện trên chứng tỏ đó là những học sinh chưa có tính kỉ luật, thiếu sự tôn trọng thầy cô giáo cũng như bạn bè, không coi trọng đến những nội quy, quy định của trường lớp. Hình thành nên tính thiếu trung thực, gian lận, không coi trọng phẩm chất đạo đức của mình dẫn đến thiếu tính kỉ luật. Nếu không sửa chữa lại những hành vi đó thì khó có thể thành một người con ngoan trò giỏi được thầy yêu bạn mến.

1.I think you ought to give up playing video games. (should)

-->I think you should give up playing video games.

2.It's necessary for me to finish the work on time. (have to)

--->I have to finish the work on time.

3.It wasn't necessary for you to clean that car. (have to)

--->You didn't have to clean that car.

4.It was quite unnecessary for you to adopt a green lifestyle. (have to)

---->You didn't have to adopt a green lifestyle.

5.It was careless of you to leave the windows open last night. (shouldn't)

----->You shouldn't have left the windows open last night.

6.It is advisable for each member in the family to share the housework equally. (should)

---->Each member in the family should share the housework equally.

7.You are required to come back home before 10 p.m. (must)

--->You must come back home before 10 p.m.

8.Lina is advised to prepare carefully in the morning. (should)

----->Lina should prepare carefully in the morning.

9.Tu is responsible for picking up litter. (have to)

------>Tu has to pick up litter.

1.You are required to ask your parents for permission before staying out late. (must)

You must ask your parents for permission before staying out late.

2.I think you ought to give up smoking immediately. (should)

I think you should give up smoking immediately.

3.It is not a good idea for me to stay up late. (shouldn't)

I shouldn't stay up late.

4.It wasn't necessary for you to send these letters. (have to)

You didn't have to send these letters.

5.It was unnecessary for Tim to finish the work. (have to)

Tim didn't have to finish the work.

6.It was careless of you to leave your children alone at home. (shouldn't)

You shouldn't have left your children alone at home.

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