HOC24
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Ta có: \(n_{Br_2}=\dfrac{8}{160}=0,05\left(mol\right)\)
PT: \(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)
_____0,05____0,05 (mol)
\(\Rightarrow V_{C_2H_4}=0,05.22,4=1,12\left(l\right)\)
\(V_{CH_4}=5,6-1,12=4,48\left(l\right)\)
Ta có: nOH- = 2nH2 = 0,4 (mol) = nH+
Gọi: V dd axit = a (l)
⇒ nH+ = a + 0,5.2.a = 0,4
⇒ a = 0,2 (l) = 200 (ml)
→ Đáp án: C
Đáp án: C
Ta có: \(n_{C_2H_4}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
PT: \(C_2H_4+3O_2\underrightarrow{t^o}2CO_2+2H_2O\)
____0,25___0,75 (mol)
\(\Rightarrow V_{O_2}=0,75.22,4=16,8\left(g\right)\)
\(V_{kk}=\dfrac{V_{O_2}}{20\%}=84\left(l\right)\)
Ta có: nN2 + nH2 = 1,3 (mol) (1)
Mà: dhh/O2 = 0,3125
\(\Rightarrow\dfrac{28n_{N_2}+2n_{H_2}}{1,3}=0,3125.32\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{N_2}=0,4\left(mol\right)\\n_{H_2}=0,9\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%V_{N_2}=\%n_{N_2}=\dfrac{0,4}{1,3}.100\%\approx30,77\%\\\%V_{H_2}\approx69,23\%\end{matrix}\right.\)
Trong 1 phần: 24nNa + 27nAl + 56nFe = 56,7:3 (1)
- Phần 1: 2nH2 = nNa + 3nNa
⇒ 4nNa = 0,2.2 (2)
- Phần 2:
BT e: nNa + 3nAl = 2nH2 = 0,35.2 (3)
Từ (1), (2) và (3) \(\Rightarrow\left\{{}\begin{matrix}n_{Na}=0,1\left(mol\right)\\n_{Al}=0,2\left(mol\right)\\n_{Fe}=0,2\left(mol\right)\end{matrix}\right.\)
BT e: 2nH2 = nNa + 3nAl + 2nFe
⇒ nH2 = 0,55 (mol)
⇒ VH2 = 0,55.22,4 = 12,32 (l)
→ Đáp án: B
Ta có: \(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
PT: \(2C_2H_5OH+2Na\rightarrow2C_2H_5ONa+H_2\)
________0,2______0,2________0,2_____0,1 (mol)
a, mC2H5OH = 0,2.46 = 9,2 (g)
b, mNa = 0,2.23 = 4,6 (g)
mC2H5ONa = 0,2.68 = 13,6 (g)
(1) \(C_2H_2+H_2\underrightarrow{^{Pd/PbCO_3,t^o}}C_2H_4\)
(2) \(C_2H_4+H_2O\underrightarrow{^{t^o,xt}}C_2H_5OH\)
(3) \(C_2H_5OH+O_2\xrightarrow[_{mengiam}]{^{t^o}}CH_3COOH+H_2O\)
(4) \(CH_3COOH+C_2H_5OH⇌CH_3COOC_2H_5+H_2O\) (Điều kiện: to, H2SO4 đặc)
(5) \(C_2H_5OH+Na\rightarrow C_2H_5ONa+\dfrac{1}{2}H_2\)
(6) \(2CH_3COOH+Ca\rightarrow\left(CH_3COO\right)_2Ca+H_2\)
Ta có: 102nAl2O3 + 80nCuO = 26,2 (1)
PT: \(Al_2O_3+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2O\)
\(CuO+H_2SO_4\rightarrow CuSO_4+H_2O\)
Theo PT: \(n_{H_2SO_4}=3n_{Al_2O_3}+n_{CuO}=0,25.2=0,5\left(mol\right)\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{Al_2O_3}=0,1\left(mol\right)\\n_{CuO}=0,2\left(mol\right)\end{matrix}\right.\)
⇒ mAl2O3 = 0,1.102 = 10,2 (g)
mCuO = 0,2.80 = 16 (g)
a, \(2CH_3COOH+CaCO_3\rightarrow\left(CH_3COO\right)_2Ca+CO_2+H_2O\)
b, \(n_{CaCO_3}=\dfrac{30}{100}=0,3\left(mol\right)\)
Theo PT: \(n_{CH_3COOH}=2n_{CaCO_3}=0,6\left(mol\right)\)
\(\Rightarrow C_{M_{CH_3COOH}}=\dfrac{0,6}{0,25}=2,4\left(M\right)\)
c, \(n_{\left(CH_3COO\right)_2Ca}=n_{CaCO_3}=0,3\left(mol\right)\)
\(\Rightarrow m_{\left(CH_3COO\right)_2Ca}=0,3.158=47,4\left(g\right)\)