Bài 1:Đốt cháy hoàn toàn 1 g HCHC A cho hấp thụ hết khí CO2 và H2O vào 1,5 lít dung dịch Ba(OH)2 0,1 M thì thu được 9,85 g kết tủa, đồng thời khối lượng bình đựng dung dịch Ba(OH)2 tăng 2,92 g. Xác định CTĐG của A
CO2 + Ba(OH)2 -----> BaCO3 + H2O (1)
0.05___0.05________0.05
TỔNGnBa(OH)2 = 0.15 (mol)
nBaCO3 (1) = 0.05 (mol)
nBa(OH)2 (2) = 0.15-0.05 = 0.1 (mol)
2CO2 + Ba(OH)2 -----> Ba(HCO3)2
_0.2____0.1_
nCO2 = 0.05+0.2 = 0.25 (mol)
mCO2 = 0.25x44 = 11 (g)
Ta có:
mdd tăng = mCO2 + mH2O - mBaCO3
<=> 2.92 = 11 + mH2O - 9.85
=> mH2O = 1.77 (g)
=> nH2O = 0.098333 (mol)
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