giúp mình vs Người ta dùng một lượng vừa đủ dung dịch FeCl3 25% cho vào dung dịch NaOH lấy dư. Sau khi phản ứng kết thúc, thu được 10,7g kết tủa A. Lọc lấy kết tủa đem đun nóng đến khi khối lượng không đổi, thu được một chất rắn B. a)Viết PTHH xảy ra b)Tính khối lượng dd FeCl3 đã tham gia phản ứng c) Tính khối lượng chất rắn B.

2 câu trả lời

Đáp án:

a/  pt:

$FeCl_{3}$ + $3NaOH$ → $Fe(OH)_{3}$↓ + $3NaCl$

                       $t^{o}$

$2Fe(OH)_{3}$ → $Fe_{2}$$O_{3}$ + $3H_{2}O$

b/$m dd_{FeCl_{3}}$ = 65 (gam)

c/$m_{Fe_{2}O_{3}}$  = (8 gam)

Giải thích các bước giải:

a/  pt:

$FeCl_{3}$ + $3NaOH$ → $Fe(OH)_{3}$↓ + $3NaCl$

                       $t^{o}$

$2Fe(OH)_{3}$ → $Fe_{2}$$O_{3}$ + $3H_{2}O$

b/

Ta có :$n_{Fe(OH)_{3}}$ = $\frac{10,7}{107}$ = 0,1 (mol)

$n_{FeCl_{3}}$ = $n_{Fe(OH)_{3}}$ = 0,1 (mol)

⇒$m dd_{FeCl_{3}}$ = $\frac{0,1 *162,5*100}{25}$ = 65(gam)

c/

ta có : chất rắn B là$Fe_{2}$$O_{3}$

⇒$n_{Fe_{2}O_{3}}$ = 0,5$n_{Fe(OH)_{3}}$ = 0,05 (mol)

⇒$m_{Fe_{2}O_{3}}$ = 0,05 * 160 = (8 gam)

Đáp án:

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Giải thích các bước giải:

 

Câu hỏi trong lớp Xem thêm

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                     A                     B                     C                     D

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                     A                     B                     C                     D

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

             A                B             C

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                   D

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

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    A. where is it found       B. is found

    C. and found it               D. which is found

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

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

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

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

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

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