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\(n_{Zn}=\dfrac{19,5}{65}=0,3\left(mol\right)\)
PTHH :
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
0,3 0,3
a) \(V_{H_2}=0,3.22,4=6,72\left(l\right)\)
b) \(H_2+O_2\rightarrow2H_2O\)
0,3 0,3
\(V_{O_2}=0,3.22,4=6,72\left(l\right)\)
\(V_{kk}=6,72.5=33,6\left(l\right)\)
nFe2O3 = 16,8/56 = 0,3 (mol)
PTHH: Fe2O3 + 3H2 -> (t°) 2Fe + 3H2O
MOL: 0,15 <--- 0,45 <--- 0,3
VH2 = 0,45 . 22,4 = 10,08 (l)
mFe2O3 = 0,45 . 160 = 72 (g)
a ) Fe2O3 + 3H2 ---> 2Fe + 3H2O
nFe = 16,8 :56 =0,3
Fe2O3 + 3H2--> 2Fe +3H2O
0,15<------0,45<---- 0,3
VH2 = 0,45.22,4=10,08(l)
mFe2O3 = 0,15.160 =24(g)
a, PT: \(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{3}{4}n_{Al}=0,15\left(mol\right)\Rightarrow V_{O_2}=0,15.22,4=3,36\left(l\right)\)
b, PT: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
Ta có: \(n_{CH_4}=\dfrac{6.10^{22}}{6.10^{23}}=0,1\left(mol\right)\)
Theo PT: \(n_{O_2}=2n_{CH_4}=0,2\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,2.22,4=4,48\left(l\right)\)
c, Ta có: \(n_S=\dfrac{3,2}{32}=0,1\left(mol\right)\)
\(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\)
PT: \(S+O_2\underrightarrow{t^o}SO_2\)
\(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
Theo PT: \(n_{O_2}=n_S+\dfrac{5}{4}n_P=0,35\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,35.22,4=7,84\left(l\right)\)
\(a,n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\\ n_{O_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
PTHH: \(2H_2+O_2\underrightarrow{t^o}2H_2O\)
bđ 0,3 0,4
pư 0,3 0,15
sau pư 0 0,25 0,3
=> H2 hết, O2 dư
\(m_{O_2\left(dư\right)}=0,25.32=8\left(g\right)\)
b) \(A_{H_2O}=0,3.6.10^{23}=1,8.10^{23}\left(phân.tử\right)\)
c) \(m_{O_2\left(pư\right)}=0,15.32=4,8\left(g\right)\)
PTHH: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
0,3<-------------------------------------0,15
\(\rightarrow m_{KMnO_4}=0,3.158=47,4\left(g\right)\)
Câu 24:
\(V_{H_2}=0,125.22,4=2,8\left(l\right)\)
→ Đáp án: D
Câu 25:
\(n_{CuO}=\dfrac{40}{80}=0,5\left(mol\right)\)
PT: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
Theo PT: \(n_{H_2}=n_{CuO}=0,5\left(mol\right)\) \(\Rightarrow V_{H_2}=0,5.22,4=11,2\left(l\right)\)
→ Đáp án: B
Câu 26:
\(m_{ZnO}=0,5.81=40,5\left(g\right)\)
→ Đáp án: A
Câu 27: B
Câu 28: B
\(a,CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\)
Vì n và V tỉ lệ thuận với nhau. Nên ta có:
\(V_{O_2}=2.V_{CH_4}=2.2,768=5,536\left(l\right)\)
\(b,V_{kk}=\dfrac{100}{21}.V_{O_2}=\dfrac{100}{21}.5,536=\dfrac{2768}{105}\left(l\right)\)
a, PT: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
Ta có: \(n_{CH_4}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
Theo PT: \(n_{O_2}=2n_{CH_4}=0,5\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,5.22,4=11,2\left(l\right)\)
b, PT: \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
Ta có: \(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{2}{3}n_{Fe}=0,2\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,2.22,4=4,48\left(l\right)\)
c, PT: \(2H_2+O_2\underrightarrow{t^o}2H_2O\)
Ta có: \(n_{H_2}=\dfrac{3}{2}=1,5\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{H_2}=0,75\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,75.22,4=16,8\left(l\right)\)
d, PT: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
Ta có: \(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{5}{4}n_P=0,25\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,25.22,4=5,6\left(l\right)\)