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\(n_{FeS_2}=\dfrac{240}{120}.80\%=1,6\left(mol\right)\)

PTHH: 4FeS₂ + 11O₂ --t^o--> 2Fe₂O₃ + 8SO₂

               1,6 -------------------------------> 3,2

2SO₂ + O₂ --t^o--> 2SO₃

3,2 --------------------> 3,2

SO₃ + H₂O ---> H₂SO₄

3,2 ----------------> 3,2

\(m_{ddH_2SO_4}=\dfrac{3,2.98}{49\%}=640\left(g\right)\)

4FeS2+11O2-to>2Fe2O3+8SO2

1,6----------------------------------3,2

2SO2+O2-to,V2O5->2SO3

3,2----------------------------3,2

SO3+H2o->H2SO4

3,2-----------------3,2

n FeS2=2 mol

H=80%

=>n FeS2=2.80%=1,6 mol

=>m H2SO4=3,2.98=313,6g

=>mdd=640g

=>B

.

Smoking isn't allowed

1 Sue wishes she hadn't bought that new book

2 Unless you walk faster, you will be late

3 Carol spent 2 hours fixing the television sets

4 I make these handicrafts by myself 

5 If I were you, I would take the bus instead of the train

II

1 She doesn't have to get up early on Saturday

2 Children mustn't be left alone in car

3 John must explain this if he want his student to succeed

4 I have to file the report this week

5 We don't have to work overtime on Saturdays

6 You mustn't drive more than 25 mph in this zone

7 She didn't have to attend the presentation yesterday

8 She has to pick up her children at school

9 You don't have to arrive before 8

10 They had to visit the doctor yesterday as they didn't feel well