Bài 1: 

1: 

a: \(\sqrt{12}+3\sqrt{48}-5\sqrt{75}\)

\(=2\sqrt{3}+12\sqrt{3}-25\sqrt{3}\)

\(=-11\sqrt{3}\)

1 A

2 A

3 A

4 B

5 B

II

1 A

2 C

3 C

4 B

5 D

1A

2D

3B

4C

5D

6A

7A

8C

9B

10C

11A

12C

13D

14C

15A

16A

17D
18C

19B

20A

21D

22A

23A

24C

25B

26C

27A

28D

29A

30 A

31 B

33 C

33 C

34 C

35 B

36 C

37 D

38 B

39 D

40 C

nHCl = 36,5 / 36,5 = 1 (mol)

Fe + 2HCl -- > FeCl2 + H2

0,5      1             0,5       0,5   (mol)

Cu + HCl -- > ( ko pứ)

=> mFe = 0,6.56 = 28 (g)

=> mCu = 34 - 28 = 6 (g)

\(\%m_{Fe}=\dfrac{28.100}{28+6}=82,35\%\)