c d d d d

1 D

2 B

3 A

4 A

5 C

6 B

7 B

8 B

9 B

10 B

11 C

12 C

13 C

14 C

15 D

D B A A C B B B B B C C C C D

1 environmental

2 Polluting

3 conservation

4 consumption

5 appliances

6 innovation

7 Ultimately

8 suggestion

9 heated

10 environmentalists

11 worried

12protection

13 seriously

14 dripping

15 reducing

environmental

polluted

conservation

consumption

appliances

innovation

ultimately

suggestion

heated

environmentalists

worried

seriously

dripping

reducing

13. C

14.C

15.A

20A 21C 22B

Bạn chụp mặt trước nữa thì mình mới giúp được hết nha

13.D

14.B

15.A

15.

\(V_{H_2O}=2V_{CO_2}\Rightarrow n_{H_2O}=2n_{CO_2}\Rightarrow\dfrac{n_{CO_2}}{n_{H_2O}}=\dfrac{1}{2}\)

Bảo toàn C: \(n_C=n_{CO_2}=1\left(mol\right)\)

Bảo toàn H: \(n_H=2n_{H_2O}=2.2=4\left(mol\right)\)

CT có dạng: \(\left(CH_4\right)n\)

                    \(\Leftrightarrow C_nH_{4n}\)

        Ta có: \(4n\le2n+2\)

                  \(\Leftrightarrow n\le1\)

`->n=1` `->` CTPT Z: CH4

`->` Chọn D

1D 2B 3C 4A 5A 6C 7A 8A 9B 10A 11C 12D 13D 14D 15A 16D 17A 18C 19C 20D 21D 22C 23C 24A 25B 26C 27D 28B 29C

\(n_{H_2SO_4}=\dfrac{50\cdot98\%}{98}=0.5\left(kmol\right)\)

\(n_{FeS_2}=\dfrac{0.5}{2}=0.25\left(kmol\right)\)

\(m_{FeS_2}=0.25\cdot120=30\left(kg\right)\)

\(m_{quặng}=\dfrac{30}{80\%}=37.5\left(kg\right)\)

\(\)