rfhiunikuji2

2 năm trước

trung hòa 200ml dd H2SO4 0.5M bằng dd NaOH 20% a. tính khối lượng dung dịch NaOh b, thay dd NaOh bằng 20,8g BaCl2 thì thu đc 20.97 gam kết tủa trắng. tính hiệu suất phản ứng

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nguyentransondhy

2 năm trước

Đáp án:

a) m dung dịch NaOH=40 gam

b) hiệu suất H%=90%

Giải thích các bước giải:

a) H2SO4 + 2NaOH -> Na2SO4 + 2H2O

Ta có: nH2SO4=0,2.0,5=0,1 mol

Theo ptpu: nNaOH=2nH2SO4=0,1.2=0,2 mol -> mNaOH=0,2.40=8 gam

-> m dung dịch NaOH=8/20%=40 gam

BaCl2 + H2SO4 -> BaSO4 + 2HCl

Ta có kết tủa là BaSO4 -> nBaSO4=20,97/233=0,09 mol

Ta có: nBaCl2=20,8/(137+35,5.2)=0,1 mol

Vì nBaCl2=nH2SO4 nên hiệu suất tính theo chất nào cũng được

-> nBaCl2 phản ứng=nH2SO4 phản ứng=nBaSO4=0,09 mol

-> hiệu suất H%=0,09/0,1=90%

giangnth

2 năm trước

Đáp án:

Giải thích các bước giải:

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trung hòa 200ml dd H2SO4 0.5M bằng dd NaOH 20% a. tính khối lượng dung dịch NaOh b, thay dd NaOh bằng 20,8g BaCl2 thì thu đc 20.97 gam kết tủa trắng. tính hiệu suất phản ứng

2 câu trả lời

if you don't wear a helmet , you can't ride your bike => Unless

Choose the best answer.
I think you should buy ___ pack of mineral water instead. And you can also buy _ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ____ cookies and soft candies.

Choose the best answer.
We should decorate our living room with _ orange banner. We also need ____ ribbons, balloons, party hats and costume.

Choose the best answer.
I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.

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trung hòa 200ml dd H2SO4 0.5M bằng dd NaOH 20% a. tính khối lượng dung dịch NaOh b, thay dd NaOh bằng 20,8g BaCl2 thì thu đc 20.97 gam kết tủa trắng. tính hiệu suất phản ứng

2 câu trả lời

if you don't wear a helmet , you can't ride your bike => Unless

Choose the best answer.I think you should buy _____ pack of mineral water instead. And you can also buy _____ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ______ cookies and soft candies.

Choose the best answer.We should decorate our living room with _____ orange banner. We also need ________ ribbons, balloons, party hats and costume.

Choose the best answer.I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.

Đề thi - đề kiểm tra Xem thêm

Choose the best answer.
I think you should buy ___ pack of mineral water instead. And you can also buy _ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ____ cookies and soft candies.

Choose the best answer.
We should decorate our living room with _ orange banner. We also need ____ ribbons, balloons, party hats and costume.

Choose the best answer.
I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.