Đáp án B

D
B

D

B

\(n_{KMnO_4}=\dfrac{79}{158}=0,5mol\)

\(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)

0,5                                                 0,25

\(H=80\%\Rightarrow n_{O_2}=0,25\cdot80\%=0,2mol\)

\(\Rightarrow V=0,2\cdot22,4=4,48l\)

\(n_{KClO_3\left(bđ\right)}=\dfrac{24,5}{122,5}=0,2\left(mol\right)\)

=> \(n_{KClO_3\left(pư\right)}=\dfrac{0,2.50}{100}=0,1\left(mol\right)\)

PTHH: 2KClO₃ --t^o--> 2KCl + 3O₂

               0,1------------------>0,15

=> V = 0,15.22,4 = 3,36 (l)

nKClO3 = 24,5/122,5 = 0,2 (mol)

PTHH: 2KClO3 -> (t°, MnO2) 2KCl + 3O2

Mol: 0,2 ---> 0,2 ---> 0,3

nO2 (TT) = 0,3 . 50% = 0,15 (mol)

VO2 (TT) = 0,15 . 22,4 = 3,36 (l)

\(a,2KMnO_4\xrightarrow{t^o}K_2MnO_4+MnO_2+O_2\\ n_{KMnO_4}=\dfrac{395}{158}=2,5(mol)\\ \Rightarrow n_{O_2}=1,25(mol)\\ \Rightarrow V_{O_2}=1,25.22,4=28(l)\\ \Rightarrow V_{O_2(tt)}=28.85\%=23,8(l)\)

\(b,n_{O_2}=\dfrac{67,2}{22,4}=3(mol)\\ 2KMnO_4\xrightarrow{t^o}K_2MnO_4+MnO_2+O_2\\ \Rightarrow n_{KMnO_4}=6(mol)\\ \Rightarrow m_{KMnO_4}=6.158=948(g)\\ \Rightarrow m_{KMnO_4(tt)}=\dfrac{948}{80\%}=1185(g)\)

\(n_{KMnO_4\left(lt\right)}=\dfrac{31.6}{158}\cdot80\%=0.16\left(mol\right)\)

\(2KMnO_4\underrightarrow{^{^{t^0}}}K_2MnO_4+MnO_2+O_2\)

\(0.16.............................................0.08\)

\(V_{O_2}=0.08\cdot22.4=1.792\left(l\right)\)

n KMnO4 = 31,6/158 =0,2(mol)

$2KMnO_4 \xrightarrow{t^o} K_2MnO_4 + MnO_2 + O_2$

n O2(lt) = 1/2 n KMnO4 = 0,1(mol)

n O2(tt) = 0,1.80% = 0,08(mol)

V O2 = 0,08.22,4 = 1,792 lít

Đáp án D

Hướng dẫn n_{anđehit phản ứng} = 12,3.80% = 9,84 gam

m_axit – m_anđehit = (45 – 29)n_anđehit →  n a n đ e h i t = 13 , 68 − 9 , 84 ( 45 − 29 ) = 0 , 24    m o l → n O 2 = 1 2 n a n đ e h i t = 0 , 12    m o l

V k k = 0 , 12.22 , 4 = 2 , 688  (lít)

Đáp án : B

CaCO₃ -> CaO + CO₂

100g                     22,4 lit

50g      ->              11,2 lit

Sửa đề đktc→đkc

\(1.\\ n_{KMnO_4}=\dfrac{31,6}{158}=0,2mol\\ n_{O_2}=0.2:2=0,1mol\\ V_{O_2}=0,1.24,79.80\%=1,9832l\)

\(2.\\ n_{C_2H_5OH}=\dfrac{6,9}{46}=0,15mol\\ n_{C_2H_4}=n_{C_2H_5OH}=0,15mol\\ V_{C_2H_4}=0,15.24,79:75\%=4,958l\)

\(3.\\ n_{C_2H_4}=\dfrac{24,79}{24,79}=1mol\\ n_{C_2H_5OH\left(tt\right)}=\dfrac{13,8}{46}=0,3mol\\ n_{C_2H_5OH\left(lt\right)}=n_{C_2H_4}=1mol\\ H=\dfrac{0,3}{1}\cdot100=30\%\)

\(4.\\ a.n_{CuO}=\dfrac{4}{80}=0,05mol\\ \)

\(CuO+H_2\xrightarrow[]{t^0}Cu+H_2O\)

\(b.n_{H_2}=n_{CuO}=0,05mol\\ V_{H_2}=0,05.24,79=1,2395l\)

\(5.\\ a.2H_2+O_2\xrightarrow[]{t^0}2H_2O\\ b.n_{H_2}=\dfrac{49,58}{24,79}=2mol\\ n_{O_2}=\dfrac{74,37}{24,79}=3mol\\ \Rightarrow\dfrac{2}{2}< \dfrac{3}{1}\Rightarrow O_2.dư\\ 2H_2+O_2\xrightarrow[]{t^0}2H_2O\)

\(2........1.........2\)

\(V_{O_2.dư}=\left(3-1\right).24,79=48,58l\\ c.m_{H_2O}=2.18=36g\)

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