1. With

2. Language

3. Play

4. Positive

1 had worked - went - is travelling

2 do you do - worked

3 had gone

4 got - had gone

5 met - hadn't seen

6 was making

7 is having

8 is making - makes

9 am wearing

10 is reading

11 borrows - remembers

12 is he doing - think - is polishing

13 saw - was painting

14 was reading

15 went 

16 was discovered

17 drinks - drank

18 does she do - plays - watches

19 are waiting 

20 had left

23 Has Nga read

24 Have they played

25 Have - already washed

26 Is -travelling

7 makes

8 started

9 are - are playing

has nga read

have they played

have ....already washed

Is ....travelling

is always making

started

are-are playing

cái này áp dụng hệ thức lượng thôi bạn

AH=căn 6^2-4,8^2=3,6cm

=>AC=6^2/3,6=10cm

1. bag

2. bunch

3. slice

4. box

5. piece

6. carton

7. can

8. bowl

9. jar

10. bottle

o.nhìn.rõ

Gọi kim loại là R, hóa trị n, do R là kim loại nên n có thể bằng 1, 2 hoặc 3

\(2R + 2nHCl \rightarrow 2RCl_n + nH_2\)

\(n_{H_2}=\dfrac{3,36}{22,4}= 0,15 mol\)

Theo PTHH:

\(n_{R}= \dfrac{2}{n} . n_{H_2}= \dfrac{2}{n} . 0,15 = \dfrac{0,3}{n} mol\)

\(\Rightarrow M_R= \dfrac{3,6}{\dfrac{0,3}{n}}=\dfrac{3,6n}{0,3}=12n\)

Do n bằng 1, 2 hoặc 3

Ta thấy n= 2 và M_R= 24 g/mol thỏa mãn

R là Mg

Gọi CTHH của kim loại là M, x là hóa trị của M

PTHH: M + xHCl ---> MCl_x + \(\dfrac{x}{2}\)H₂.

Ta có: \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

Theo PT: \(n_M=\dfrac{1}{\dfrac{x}{2}}.n_{H_2}=\dfrac{1}{\dfrac{x}{2}}.0,15=\dfrac{2}{x}.0,15=\dfrac{0,3}{x}\left(mol\right)\)

=> \(M_M=\dfrac{3,6}{\dfrac{0,3}{x}}=\dfrac{3,6x}{0,3}=12x\left(g\right)\)

Biện luận:

Vậy M_M = 24(g)

Dự vào bảng hóa trị, suy ra:

M là magie (Mg)