II.

1. C

2. D

3. D

4. B

5. D

6. A

7. C

8. D

9. A

10. C

11. A

12. C

13. B

14. D

15. B

16. C

17. A

18. B

19. C

20. D

III.

1. F

2. H

3. G

4. A

5. I

6. J

7. E

8. C

9. D

10. B

S hinh thang ABCD la:

24+[24+10+10]*18\2=612[cm2]

A la 612

S tam giac BEC la:

18*10\2 =90[cm2]

B la 90

S tam giac BEC + S hinh thang ABCD la:

612+90 = 702[cm2]

C la 702 

B la 90

C la 102

CH₃COOH + NaHCO₃ \(\rightarrow\) CH₃COONa + H₂O + CO₂\(\uparrow\) (1)

a) Ta có: \(m_{NaHCO_3}=\dfrac{20\cdot500}{100}=100\left(g\right)\)

\(\Rightarrow n_{NaHCO_3}=\dfrac{100}{84}\approx1,2\left(mol\right)\)

Theo phương trình (1): \(n_{CH_3COOH}=n_{NaHCO_3}=1,2\left(mol\right)\)

\(\Rightarrow m_{CH_3COOH}=1,2\cdot60=72\left(g\right)\)

Do đó: \(C\%_{CH_3COOH}=\dfrac{72}{300}\cdot100\%=24\%\)

Số cần tìm là:

    10x100:100=10

          Đáp số:10

1) The holiday was so disappointing that they decided to ask for giving money back.

2) If there is so much exhaust fume in the air, more people will cope with respiratory problems.

3) Do you know the name of the lecturer talking about natural disasters in the workshop two days ago?

cho minh đi

C. in

a)S tam giac=20x30=600

ba la tam

bon la tu

tam tu

tu tam

Choose A, B, C or D to complete the following sentences.

Tom has to go to the bus stop if he wants to go _______ bus.

A. at

B. on

C. in

D. by