Ta có : nAl = 8,1/ 27 = 0,3mol

nHCl = 182,5*20/100*36,5= 1 mol

PTHH : Al + 2HCl -> AlCl2 + H2

tỷ lệ : 0,3/ 1< 1/2 -> HCl dư

nH2 = n Al = 0,3 mol

-> VH2 = 0,3 * 22,4 = 6,72 l

Dung dịch thu được có 2 chất: - HCl

- AlCl2

Ta có : nHCl đã phản ứng: 0,3*2/1=0,6 mol

-> nHCl dư = 1 - 0,6 = 0,4 mol

-> mHCl dư = 0,4 * 36,5 = 14,6 g

Ta có : nAlCl2 = 0,3 mol

-> mAlCl2 = 0,3 * 98 = 29,4 g

Ta có mH2 = 0,3 * 2 = 0,6 g

mdd sau phản ứng : 8,1+ 182,5- 0,6 =190 g

C% HCl= 14,6*100/ 190=7,68 %

C% AlCl2= 29,4* 100/ 190=15,47%

Ta có pthh : Fe + 2HCl -> FeCl2 + H2

a, Tacó : nHCl= 1,6* 0,5 = 0,8 mol

Từ PTHH nFe = 1/2nHCl = 0,4 mol

-> mFe = 0,4 *56 = 22,4 g

b, Ta có : nH2 = nFe = 0,4mol

-> VH2= 0,4 * 22,4 = 8,96 l

c, Ta có : V FeCl2= 1,6 l

nFeCl2 = nFe = 0,4 mol

-> Cm FeCl2 = 0,4/1,6=0,25 M

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 25 to 29. Fill in the appropriate word in question 29

          It can take a long time to become successful in your chosen field, however talented you are. One thing you have to be aware of is that you will face criticism along the way. The world is full of people who would rather say something negative than positive. If you’ve made up your (25) ______ to achieve a certain goal, such as writing a novel, don’t let the negative criticism of others prevent you from reaching your target, and let the constructive criticism have a positive effect on your work. If someone says you’re totally in the (26) _______ of talent, ignore them. That’s negative criticism. If, (27) ________, someone advises you to revise your work and gives you a good reason for doing so, you should consider their suggestions carefully. There are many film stars who were once out of work. There are many famous novelists who made a complete mess of their first novel – or who didn’t, but had to keep on approaching hundreds of publishers before they could get it (28) _______. Being successful does depend on luck, to a certain extent. But things are more likely to (29) _______ well if you persevere and stay positive.

A. sail through

B. turn out

C. deal with

D. come into

Ta có pthh: 2H2 + O2 -> 2H2O

ta có nH2= 112/22,4=5 mol

mà : nH2O = nH2= 5 mol

-> VH2O= 5*22,4= 112 l

câu đầu là : 4Na+ O2-> 2Na2O

Na+ O2-> 2Na2O

2Mg + O2 -> 2MgO

4Al + 3O2 -> 2Al2O3

4P + 5O2 -> 2P2O5

C + O2-> CO2