đốt cháy hết m gam p(photphorus) cần dùng v lít khí khi o2(dktc-25độ c l) thu đc 22,72gam p2o5 tính a.m=? b.V=?
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Câu 1:
\(4P+5O_2\rightarrow2P_2O_5\)
\(n_P=\dfrac{15.5}{31}=0.5\left(mol\right)\)
\(\Leftrightarrow n_{P_2O_5}=0.25\left(mol\right)\)
\(\Leftrightarrow m_{P_2O_5}=0.25\cdot142=35.5\left(g\right)\)
Câu 1:
4P + 5O2 \(\underrightarrow{t^o}\) 2P2O5
\(n_P=\dfrac{15,5}{31}=0,5mol\)
\(n_{O_2}=\dfrac{0,5.5}{4}=0,625mol\)
\(V_{O_2}=0,625.22,4=14l\)
\(n_{P_2O_5}=\dfrac{0,5.2}{4}=0,25mol\\ m_{P_2O_5}=0,25.142=35,5g\)
Câu 2:
4P + 5O2 \(\underrightarrow{t^o}\) 2P2O5
\(n_P=\dfrac{15,5}{31}=0,625mol\\ n_{P_2O_5}=\dfrac{0,625.2}{4}=0,25mol\\ m_{P_2O_5}=0,25.142=35,5g\)
\(Bài.2.có.nhiều.cách.làm.nhé.bạn\)
a, Theo giả thiết ta có: \(n_P=\dfrac{3,1}{31}=0,1\left(mol\right)\)
\(4P+5O_2--t^o->2P_2O_5\)
Ta có: \(n_{O_2}=\dfrac{5}{4}.n_P=0,125\left(mol\right)\Rightarrow V_{O_2\left(đktc\right)}=0,125.22,4=2,8\left(l\right)\)
b, Theo giả thiết ta có: \(n_{CH_4}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)
\(CH_4+2O_2--t^o->CO_2+2H_2O\)
Ta có: \(n_{O_2}=2.n_{CH_4}=0,1\left(mol\right)\Rightarrow V_{O_2\left(đktc\right)}=2,24\left(l\right)\)
PTHH: \(4P+5O_2\xrightarrow[]{t^o}2P_2O_5\)
Ta có: \(n_P=\dfrac{9,3}{31}=0,3\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{O_2}=0,375\left(mol\right)\\n_{P_2O_5}=0,15\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{O_2}=0,375\cdot22,4=8,4\left(g\right)\\m_{P_2O_5}=0,15\cdot142=21,3\left(g\right)\end{matrix}\right.\)
\(n_{O_2\left(đktc\right)}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\ 4P+5O_2\underrightarrow{^{to}}2P_2O_5\\ 0,12........0,15.........0,06\left(mol\right)\\ m_P=0,12.31=3,72\left(g\right)\)
\(n_P=\dfrac{9.3}{31}=0.3\left(mol\right)\)
\(4P+5O_2\underrightarrow{^{^{t^0}}}2P_2O_5\)
\(0.3.....0.375.....0.15\)
\(V_{O_2}=0.375\cdot22.4=8.4\left(l\right)\)
\(m_{P_2O_5}=0.15\cdot142=21.3\left(g\right)\)
PT: 4P + 5O2 → 2P2O5.
Ta có: nP= 9,3/31=0,3(mol)
Theo PT: nO2= 5/4 . nP=5/4 . 0,3=0,375(mol)
=> VO2=0,375.22,4=8,4(lít)
Theo PT: nP2O5=1/2 . nP=1/2 . 0,3=0,15(mol)
=> mP2O5= 0,15.142=21,3(g)
\(\left(a\right)\)\(4Al+3O_2\underrightarrow{t^0}2Al_2O_3\)
\(\left(b\right)\)\(n_{Al}=\dfrac{4.05}{27}=0.15\left(mol\right)\)
\(\Rightarrow n_{O_2}=\dfrac{3}{4}n_{Al}=0.1125\left(mol\right)\Rightarrow V_{O_2}=2.52\left(l\right)\)
\(\Rightarrow n_{Al_2O_3}=\dfrac{n_{Al}}{2}=\dfrac{0.15}{2}=0.075\left(mol\right)\)
\(m_{Al_2O_3}=0.075\cdot102=7.65\left(g\right)\)
\(\left(c\right)\)
Để điều chế : 7.65 (g) Al2O3 thì cần 4.05 (g) Al và 2.52(l) khí O2
Vậy : để điều chế 25.5(g) Al2O3 thì cần x(g) Al và y(l) khí O2
\(m_{Al}=\dfrac{25.5\cdot4.05}{7.65}=13.5\left(g\right)\)
\(V_{O_2}=\dfrac{25.5\cdot2.52}{7.65}=8.4\left(l\right)\)
a) PTHH: \(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
b) Ta có: \(n_{Al}=\dfrac{4,05}{27}=0,15\left(mol\right)\)
\(\Rightarrow n_{Al_2O_3}=0,075mol\) \(\Rightarrow m_{Al_2O_3}=0,075\cdot102=7,65\left(g\right)\)
c) Ta có: \(n_{Al_2O_3}=\dfrac{25,5}{102}=0,25\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{Al}=0,5mol\\n_{O_2}=0,375mol\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Al}=0,5\cdot27=13,5\left(g\right)\\V_{O_2}=0,375\cdot22,4=8,4\left(l\right)\end{matrix}\right.\)
a, \(n_P=\dfrac{24,8}{31}=0,8\left(mol\right)\)
\(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
\(n_{O_2}=\dfrac{5}{4}n_P=1\left(mol\right)\) \(\Rightarrow V_{O_2}=1.22,4=2,24\left(l\right)\)
b, \(n_{P_2O_5}=\dfrac{1}{2}n_P=0,4\left(mol\right)\Rightarrow m_{P_2O_5}=0,4.142=56,8\left(g\right)\)
c, \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
\(n_{KMnO_4}=2n_{O_2}=2\left(mol\right)\Rightarrow m_{KMnO_4}=2.158=316\left(g\right)\)
\(n_P=\dfrac{m}{M}=\dfrac{24,8}{31}=0,8\left(mol\right)\)
\(PTHH:4P+5O_2\underrightarrow{t^o}2P_2O_5\)
4 5 2
0,8 1 0,4
\(a.V_{O_2}=n.24,79=1.24,79=24,79\left(l\right)\\ b.m_{P_2O_5}=n.M=0,4.\left(31.2+16.5\right)=56,8\left(g\right)\)
\(c.PTHH:2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2\downarrow+O_2\uparrow\)
2 1 1 1
0,8 0,4 0,4 0,4
\(m_{KMnO_4}=n.M=0,8.\left(39+55+16.4\right)=126,4\left(g\right).\)
\(n_{P_2O_5}=\dfrac{22,72}{142}=0,16mol\\ 4P+5O_2\xrightarrow[]{t^0}2P_2O_5\\ a.n_P=0,16\cdot\dfrac{4}{2}=0,32mol\\ m=m_P=0,32.31=9,92g\\ b.n_{O_2}=0,16\cdot\dfrac{5}{2}=0,4mol\\ 0V=V_{O_2}=0,4.22,4=8,96l\)