/s/: stops, arts, laughs, rocks

/iz/: quizzes, fixes, watches

/z/: friends, prefers

/ɪz/: quizzes, fixes, watches

/s/: stops, arts, laughs, rocks

/z/: friends, prefers

1. To learn the regulations is difficult

=> it is...difficult to learn the regulations.

2. To pratise swimming is good for your health

=> it is good for your health to practice swimming.

3. To help him write his name on the board was necessary

=> it was...necessary to help him write his name on the board.

4. To get acquainted with newcomers is easy

=> it is not... difficult to get acquainted with newcomers.

1. To learn the regulations is difficult

=> it is...difficult to learn the regulations

2. To pratise swimming is good for your health

=> it is good for your health to practise swimming

3. To help him write his name on the board was necessary

=> it was...necessary to help him write his name on the board 

4. To get acquainted with newcomers is easy

=> it is not... difficult to get acquainted with newcomers

1. Do you agree .with.. me .on..this problem?

2. Making friends is easy .for.. him

3. Let's listen ..to. what he says

4. I cannot help you now because i am ..in. a hurry

5. What are you afraid .of..?

6. The street is crowded .with.. people

7. He was born .on.. June 15th , 1987

8. I intend to buy something .for.. my mother

9. Tom often takes a bus .to.. his school

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5 of

6 with

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8 for

9 to

#\(yGLinh\)

\(n_{co_2}=\dfrac{0,896}{22,4}=0,02\left(mol\right)\)

\(n_{BaCl_2}=\dfrac{100.20,8\%}{208}=0,1\left(mol\right)\)

PTHH : 

\(BaCl_2+Na_2CO_3\rightarrow BaCO_3+2NaCl\) (1)

Như vậy : dung dịch X gồm \(BaCO_3;NaCl;\) có thể có \(BaCl_2\) dư hoặc \(Na_2CO_3\) dư

PTHH : 

\(BaCO_3+H_2SO_4\rightarrow BaSO_4+CO_2+H_2O\) (2)

ctc : \(Na_2CO_3+H_2SO_4\rightarrow Na_2SO_4+CO_2+H_2O\) (3)

+) TH1 : Nếu \(BaCl_2\) dư ( không có phản ứng (3) )

Theo phương trình (2) \(\Rightarrow n_{BaCO_3}=n_{CO_2}=0,04\left(mol\right)\)

Theo phương trình (1) \(\Rightarrow n_{Na_2CO_3}=n_{BaCO_3}=0,04\left(mol\right)\)

\(\Rightarrow m_{Na_2CO_3}=0,04.106=4,24\left(g\right)\)

\(\Rightarrow C_{\%ddNa_2CO_3}=\dfrac{4,24.100\%}{100}=4,24\%\)

BTKL \(\Rightarrow m_{ddBaCl_2}+m_{ddNa_2CO_3}+m_{ddH_2SO_4}=m_{ddspứ}+m_{CO_2}\)

\(\Rightarrow m_{ddBaCl_2}+m_{ddNa_2CO_3}+m_{ddH_2SO_4}-m_{CO_2}=m_{ddspứ}\)

\(\Rightarrow m_{ddspứ}=100+100+100-0,04.44=298,14\left(g\right)\)

+) TH2 : Nếu \(Na_2CO_3\) dư ( xảy ra phản ứng (3) )

Theo phương trình (1) \(\Rightarrow n_{BaCO_3}=n_{BaCl_2}=0,1\left(mol\right)\)

Theo phương trình (2) \(\Rightarrow n_{CO_2\left(2\right)}=n_{BaCO_3\left(1\right)}=0,1\left(mol\right)>0,04\left(mol\right)\) ( vô lí ) 

\(\Rightarrow\) TH2 loại

1 of

2 in- to 

3 with

4 with

5 with

6 with

#\(yGLinh\)

1. What are you fond ..of.

2.The schoolboys and schoolgirls gathered .in.. small groups and talked .to.. one another

3. It is difficcult to get acquainted ..with. newcomers

4. My from teacher is rather strict ..with. us

5. They look at their new school .with.. curious eyes

6. The pupils were busy ..with. their work

Sửa đề: Kẻ đường thẳng vuông góc với NP tại P và đường thẳng vuông góc với MQ tại Q, hai đường thẳng này cắt nhau tại E

Gọi K là giao điểm của MQ và NP

Xét ΔKQE vuông tại Q và ΔKPE vuông tại P có

KE chung

EQ=EP

Do đó: ΔKQE=ΔKPE

=>KQ=KP

=>ΔKQP cân tại K

=>\(\hat{KQP}=\hat{KPQ}\)

=>\(\hat{MQP}=\hat{NPQ}\)

Hình thang MNPQ có \(\hat{MQP}=\hat{NPQ}\)

nên MNPQ là hình thang cân

1 At

2 of

3 in - to

4 in

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6 into

#\(yGLinh\)

1 at

2 of

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4 in

5 to

5 into

1 She arrived in Hanoi on Monday morning.
2 My father used to take me to the zoo when I was a child.
3 She is busy with her housework now.
4 Her performance made a deep impression on the audience.
5 Tom is very friendly with his classmates.
6 I saw you walking past the mosque on the way to my school.

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Xét ΔABC vuông tại A có \(sinACB=\dfrac{AB}{BC}\)

=>\(\dfrac{5}{BC}=sin30=\dfrac{1}{2}\)

=>BC=10(cm)

ΔABC vuông tại A

=>\(AB^2+AC^2=BC^2\)

=>\(AC=\sqrt{10^2-5^2}=5\sqrt{3}\left(cm\right)\)

- Nguyên tử khối của Nitơ là khoảng 14 amu. ( 14g/mol )
- Nguyên tử khối của Helium là khoảng 4 amu. ( 4g/mol )

có lời giải chi tiết k ạ