Bài 2: Hòa tan hoàn toàn 1,6 g CuO trong 100g dd H,SO, 20%. Hãy tính nồng độ % các chất có trong dung dịch sau phản ứng. Bài 3: Có những chất sau: ZnO, Mg, CO2, Fe(OH)2, BaO, Ag, Fe, SO2 Mg(OH)2 . Những chất nào tác dụng được với: a) Dung dịch KOH. b) Dung dịch HCI. c) Nước Viết các phương trình phản ứng.

2 câu trả lời

Đáp án:

 

Giải thích các bước giải:

 Bài 2:

$n_{CuO}=\frac{1,6}{80}=0,02 mol$

$n_{H_2SO_4}=\frac{100.20}{100.98}=\frac{10}{49} mol$

$CuO + H_2SO_4 \to CuSO_4 + H_2O$

Theo phương trình:

$n_{H_2SO_4 phản ứng} = n_{CuO} = n_{CuSO_4}=0,02 mol$

$n_{H_2SO_4 dư} = \frac{10}{49} - 0,02=0,184 mol$

$m_{Dung dịch} = 1,6 + 100 = 101,6g$

$C_{CuSO_4}\%=\frac{0,02.160.100}{101,6}=3,15\%$

$C_{H_2SO_4 du}\%=\frac{0,18.98.100}{101,6}=17,36\%$

Bài 3:

a) Những chất tác dụng được với dung dịch KOH: $ZnO$, $CO_2$, $BaO$, $SO_2$

$ZnO + 2KOH \to K_2ZnO_2 + H_2O$

$CO_2 + 2KOH \to K_2CO_3 + H_2O$

$BaO + H_2O \to Ba(OH)_2$

$SO_2 + 2KOH \to K_2SO_3 + H_2O$

b) Những chất tác dụng được với dung dịch HCl: $ZnO$,$Mg$, $CO_2$, $Fe(OH)_2$, $BaO$, $SO_2$

$Fe$

$ZnO + 2HCl \to ZnCl_2 + H_2O$

$Mg + 2HCl \to MgCl_2 + H_2$

$CO_2 + H_2O ⇄ H_2CO_3$

$Fe(OH)_2 + 2HCl \to FeCl_2 + 2H_2O$

$BaO + 2HCl \to FeCl_2 + H_2O$

$Fe + 2HCl \to FeCl_2 + H_2$

$SO_2 + 2HCl ⇄ H_2SO_3$

c) Những chất tác dụng được với dung dịch H_2O: $CO_2$, $BaO$, $SO_2$

$CO_2 + H_2O ⇄ H_2CO_3$

$SO_2 + 2HCl ⇄ H_2SO_3$

$BaO + H_2O \to Ba(OH)_2$

nCuO=1,680=0,02(mol)
nH2SO4=100.20%98=1049

CuO+H2SO4→CuSO4+H2O

nCuO<nH2SO4 nên $H_2SO_4 dư

Theo PTHH :
nCuSO4=nH2SO4 pư=nCuO=0,02(mol)

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I.  MULTIPLE CHOICE (8.0 points)

Mark the letter A, B, C, or D to indicate the word whose underlined part is pronounced differently front that of the rest in each of the following questions.

1. A. oceanic    B. remote    C. occasion    D. metro

2. A. festival    B. cultural    C. sculpture    D. virtual

Mark the letter A, B, C, or D to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

3. A. external    B. determine    C. mysterious    D. customer

4. A. miraculous    B. individual    C. certificate    D. astronomy

Mark the letter A, B, C, or D to indicate the underlined part that needs correction in each of the following questions.

5. Now that the stress of examinations are over, we can go somewhere for our holiday.

                     A                     B                     C                     D

6. The English summer course will start in May 29th and finish in August.

                     A                     B                     C                     D

7. There were so a lot of people trying to leave the burning building that the police

             A                B             C

had a great deal of trouble controlling them.

                   D

Mark the letter A, B, C, or D to indicate the correct answer to each of the following questions.

8. The earthworm is a worm _______in moist, warm soil in many geographical areas.

    A. where is it found       B. is found

    C. and found it               D. which is found

9. Our flight from Amsterdam to London was delayed    the heavy fog.

    A. as a result     B. on account     C. instead of     D. due to

10. It is_______ to translate each lesson into your language. This is not a good way to study English.

    A. productive     B. unproductive     C. producing     D. unproducing

11. A good clock always keeps_______ time.

    A. certain    B. accurate    C. true    D. serious

12. It seems that the world record for this event is almost impossible to_______.

    A. meet    B. compare    C. beat    D. balance

13. The soldier was punished for_______ to obey his commanding officer's order.

    A. refusing    B. regretting    C. objecting    D. resisting

14. It is believed that she'll be a billionaire by the time she_______ forty.

    A. is    B. was    C. will be    D. would be

15. Some of the passengers spoke to reporters about their_______ in the burning bus.

    A. occasion    B. happening    C. event    D. experience

16. _______the rise in unemployment, people still seem to be spending more.

    A. Nevertheless    B. Meanwhile    C. Despite    D. Although

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