If John is late, we will wait for him.

If it rains, we will cancel the trip

If I have time, I will watch a movie.

If we don't hurry up, we will miss our flight.

Katy will be mad if Sam is late again.

Last night I played my guitar loudly and the neighbors complained.

She kissed me on the cheek.

It rained yesterday.

Angela watched TV all night.

John wanted to go to the museum.

We were just talking about it before you arrived. 

He wasn’t working when his boss came yesterday.

Was your mother going to the market at 7 A.M yesterday? 

When I was singing in the bathroom, my mother came in.

The man was sending his letter in the post office at that time.

It has been 2 months since I first met him.

I have watched TV for two hours. 

 She has prepared for dinner since 6.30 p.m. 

He has eaten this kind of food several times before.

Have you been to that place before? 

They have worked for this company for 5 years

Đk loại 1

If I am hungry, I will get something to eat.

If I don’t see him this afternoon, I will phone him in the evening. 

If it rains we may get wet

If John has the money, he will buy a Ferrari 

She’ll be cold if she doesn’t wear a coat

Quá khứ đơn:

I was at my uncle’s house yesterday afternoon.

They didn’t accept our offer. 

We vistied Australia last summer

Did Cristiano play for Manchester United

What did you do last Sunday?

Quá khứ tiếp diễn:

He was cooking dinner at 4 p.m yesterday.

They were playing soccer when I came yesterday

He wasn’t working when his boss came yesterday.

We weren’t watching TV at 9 p.m yesterday. 

Was your mother going to the market at 7 a.m yesterday?

Hiện tại hoàn thành:

I have watched TV for two hours

She has prepared for dinner since 6.30 p.m

 He has eaten this kind of food several times before. 

We haven’t met each other for a long time. 

He hasn’t come back to his hometown since 2000.

1 send - will receive 

2 do - will improve

3 find - will give

4 will go - has

5 will go - gets

6 doesn't phone - will leave

7 don't study - won't pass

8 rains - won't have to

9 won't be able to - watch

10 cann't move - isn't

11 study - will pass

12 shines - will walk

13 has - will see

14 come - will be

15 earns - will fly

16 travel - will visit

17 wear - will slip

18 forgets - will give

19 go - will listen

C

chịu , nếu học lớp 9 còn biếc nhưng rấc tiếc mình mới lớp 8 nếu chờ được đến 5h chiều nay mình lên trường hỏi cô thì may ra còn béc:")

1. Tuổi từ 16 đến 30

2. Chịu khó học tập, lao động

3. Được tìm hiểu về Đoàn

4. Có lý lịch rõ ràng

Câu 3 : 

\(S\underrightarrow{1}SO_2\underrightarrow{2}SO_3\underrightarrow{3}H_2SO_4\underrightarrow{4}BaSO_4\)

(1) \(S+O_2\underrightarrow{t^o}SO_2\)

(2) \(2SO_2+O_2\underrightarrow{t^o,V_2O_5}2SO_3\)

(3) \(SO_3+H_2O\rightarrow H_2SO_4\)

(4) \(H_2SO_4+BaCl_2\rightarrow2HCl+BaSO_4\)

 Chúc bạn học tốt

\(\left(1\right)S+O_2\rightarrow^{\left(t^0\right)}SO_2\\ \left(2\right)2SO_2+O_2\rightarrow^{\left(t^0,V_2O_5\right)}2SO_3\\ \left(3\right)SO_3+H_2O\rightarrow H_2SO_4\\ \left(4\right)H_2SO_4+BaO\rightarrow BaSO_4+H_2O\)

\(S+O_2\xrightarrow[]{t^o}SO_2\)

\(SO_2+\dfrac{1}{2}O_2\xrightarrow[V_2O_5]{t^o}SO_3\)

\(SO_3+H_2O\rightarrow H_2SO_4\)

\(H_2SO_4+BaO\rightarrow BaSO_4+H_2O\)

Câu 3 : 

\(S\underrightarrow{1}SO_2\underrightarrow{2}SO_3\underrightarrow{3}H_2SO_4\underrightarrow{4}BaSO_4\)

(1) \(S+O_2\underrightarrow{t^o}SO_2\)

(2) \(2SO_2+O_2\underrightarrow{t^o,V_2O_5}2SO_3\)

(3) \(SO_3+H_2O\rightarrow H_2SO_4\)

(4) \(H_2SO_4+BaCl_2\rightarrow2HCl+BaSO_4\)

 Chúc bạn học tốt

Câu 3 : 

\(Ca\underrightarrow{1}CaO\underrightarrow{2}Ca\left(OH\right)_2\underrightarrow{3}CaCO_3\underrightarrow{4}CO_2\)

(1) \(Ca+O_2\underrightarrow{t^o}CaO\)

(2) \(CaO+H_2O\rightarrow Ca\left(OH\right)_2\)

(3) \(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)

(4) \(CaCO_3\underrightarrow{t^o}CaO+CO_2\)

 Chúc bạn học tốt

\(Ca+\dfrac{1}{2}O_2\rightarrow CaO\)

\(CaO+H_2O\rightarrow Ca\left(OH\right)_2\)

\(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)

\(CaCO_3\xrightarrow[]{t^o}CaO+CO_2\)

1)

a)

$C_2H_4 + H_2O \xrightarrow{t^o,xt} C_2H_5OH$
$C_2H_5OH + O_2 \xrightarrow{men\ giấm} CH_3COOH + H_2O$

$CH_3COOH + NaOH \to CH_3COONa + H_2O$

b)

$CH_3COOH + C_2H_5OH \buildrel{{H_2SO_4}}\over\rightleftharpoons CH_3COOC_2H_5 + H_2O$

2)

a) $n_{CO_2} = \dfrac{16,8}{22,4} = 0,75(mol)$
$C_6H_{12}O_6 \xrightarrow{men\ rượu} 2CO_2 + 2C_2H_5OH$
$n_{glucozo} = \dfrac{1}{2}n_{CO_2} = 0,375(mol)$
$m_{glucozo} = 0,375.180 = 67,5(gam)$

b) $n_{C_2H_5OH} = n_{CO_2} = 0,75(mol)$
$m_{C_2H_5OH} = 0,75.46 = 34,5(gam)$

$V_{C_2H_5OH} = \dfrac{34,5}{0,8}=  43,125(ml)$

Câu 1:

a, \(C_2H_4+H_2O\underrightarrow{t^o,xt}C_2H_5OH\)

\(C_2H_5OH+O_2\underrightarrow{mengiam}CH_3COOH+H_2O\)

\(CH_3COOH+Na\rightarrow CH_3COOH+\dfrac{1}{2}H_2\)

b, \(CH_3COOH+C_2H_5OH⇌CH_3COOC_2H_5+H_2O\) (xt: H₂SO₄ đặc, t^o)

Câu 2:

a, \(n_{CO_2}=\dfrac{16,8}{22,4}=0,75\left(mol\right)\)

\(C_6H_{12}O_6\underrightarrow{t^o,xt}2C_2H_5OH+2CO_2\)

Theo PT: \(n_{C_6H_{12}O_6}=\dfrac{1}{2}n_{CO_2}=0,375\left(mol\right)\)

\(\Rightarrow m_{C_6H_{12}O_6}=0,375.180=67,5\left(g\right)\)

b, \(n_{C_2H_5OH}=n_{CO_2}=0,75\left(mol\right)\Rightarrow m_{C_2H_5OH}=0,75.46=34,5\left(g\right)\)

\(\Rightarrow V_{C_2H_5OH}=\dfrac{34,5}{0,8}=43,125\left(ml\right)\)