4P+5O2-to>2P2O5

0,04----0,05----0,02

n P=0,04 mol

=>m P2O5=0,02.142=2,84g

=>VO2=0,05.22,4=1,12l

c)

2KMnO4-to>K2MnO4+MnO2+O2

0,1----------------------------------------0,05

H=10%

m KMnO4=0,1.158.110%=17,28g

\(n_P=\dfrac{1,24}{31}=0,04\left(mol\right)\\ pthh:4P+5O_2\underrightarrow{T^O}2P_2O_5\) 
          0,04  0,05       0,02 
=> \(\left\{{}\begin{matrix}m_{P_2O_5}=0,02.142=2,84\left(g\right)\\V_{O_2}=0,05.22,4=1,12\left(l\right)\end{matrix}\right.\) 
\(pthh:2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
            0,1                                             0,05          
=> \(m_{KMnO_4}=0,1.158=15,8\left(g\right)\) 
\(m_{KMnO_4\left(d\text{ùng}\right)}=15,8.110\%=17,38\left(g\right)\)

a)

\(4P + 5O_2 \xrightarrow{t^o} 2P_2O_5\)

b)

Ta có : \(n_P = \dfrac{3,1}{31} = 0,1(mol)\)

Theo PTHH : 

\(n_{P_2O_5} = 0,5n_P = 0,05(mol)\\ n_{O_2} = \dfrac{5}{4}n_P = 0,125(mol)\)

Suy ra : 

\(m_{P_2O_5} = 0,05.142 = 7,1(gam)\\ V_{O_2} = 0,125.22,4 = 2,8(lít)\)

a) PTHH: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

b) Ta có: \(n_P=\dfrac{3,1}{31}=0,1\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{O_2}=0,125mol\\n_P=0,05mol\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{P_2O_5}=0,05\cdot142=7,1\left(g\right)\\V_{O_2}=0,125\cdot22,4=2,8\left(l\right)\end{matrix}\right.\)

1. PTHH: 4P + 5O₂  2P₂O₅

2. 

Từ PT  nO2=0,125(mol);nP2O5=0,05(mol)

đktc: VO2=0,125.22,4=2,8(l)

3. mP2O5=0,05.142=7,1(g)

\(n_{KMnO_4}=\dfrac{18.96}{158}=0.12\left(mol\right)\)

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

\(0.12...........................................0.06\)

\(V_{O_2}=0.06\cdot22.4=1.344\left(l\right)\)

\(n_{Al}=\dfrac{5.4}{27}=0.2\left(mol\right)\)

\(4Al+3O_2\underrightarrow{t^0}2Al_2O_3\)

\(0.08.....0.06.......0.04\)

\(m_{Al\left(dư\right)}=\left(0.2-0.08\right)\cdot27=3.24\left(g\right)\)

\(m_{Al_2O_3}=0.04\cdot102=4.08\left(g\right)\)

a)PTHH: \(2KClO_3\xrightarrow[MnO_2]{t^o}2KCl+3O_2\uparrow\)

b) Ta có: \(n_{KClO_3}=\dfrac{49}{122,5}=0,4\left(mol\right)\) \(\Rightarrow n_{O_2}=0,6\left(mol\right)\)

\(\Rightarrow V_{O_2}=0,6\cdot22,4=13,44\left(l\right)\)

c) PTHH: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

Theo PTHH: \(n_P=\dfrac{4}{5}n_{O_2}=0,48\left(mol\right)\)

\(\Rightarrow m_P=0,48\cdot31=14,88\left(g\right)\)

a, PT: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

b, Ta có: \(n_{P_2O_5}=\dfrac{7,1}{142}=0,05\left(mol\right)\)

Theo PT: \(n_P=2n_{P_2O_5}=0,1\left(mol\right)\)

\(\Rightarrow m_P=0,1.31=3,1\left(g\right)\)

\(n_{O_2}=\dfrac{5}{2}n_{P_2O_5}=0,125\left(mol\right)\)

\(\Rightarrow V_{O_2}=0,125.22,4=2,8\left(l\right)\)

c, Có: \(V_{O_2\left(dư\right)}=2,8.15\%=0,42\left(l\right)\)

\(\Rightarrow V_{O_2}=2,8+0,42=3,22\left(l\right)\)

nP= 0,2(mol)

a) PTHH: 4P + 5 O2 -to-> 2 P2O5

0,2_________0,25_____0,1(mol)

b) V(O2,đktc)=0,25 x 22,4= 5,6(l)

c) mP2O5=142 x 0,1=14,2(g)

O

Bài 1: Tìm thể tích khí O2 (đktc) cần dùng để đốt cháy hoàn toàn 6,2 gam Photpho tạo ra hợp chất đi photpho penta oxit (P2O5). (Cho biết: P = 31; O = 16

a, \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

b, \(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\)

\(n_{O_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,2}{4}< \dfrac{0,4}{5}\), ta được O₂ dư.

Theo PT: \(n_{O_2\left(pư\right)}=\dfrac{5}{4}n_P=0,25\left(mol\right)\Rightarrow n_{O_2\left(dư\right)}=0,4-0,25=0,15\left(mol\right)\)

\(\Rightarrow m_{O_2\left(dư\right)}=0,15.32=4,8\left(g\right)\)

c, Theo PT: \(n_{P_2O_5}=\dfrac{1}{2}n_P=0,1\left(mol\right)\Rightarrow m_{P_2O_5}=0,1.142=14,2\left(g\right)\)

d, \(m_{P_2O_5}=14,2.80\%=11,36\left(g\right)\)

Giúp mik vs T-T

PTHH: \(2KMnO_4\xrightarrow[]{t^o}K_2MnO_4+MnO_2+O_2\)

\(n_{KMnO_4}=\dfrac{m_{KMnO_4}}{M_{KMnO_4}}=\dfrac{15,8}{158}=0,1\left(mol\right)\)

a. Theo PTHH: \(n_{O_2}=\dfrac{1}{2}n_{KMnO_4}=\dfrac{1}{2}0,1=0,05\left(mol\right)\)

\(\Rightarrow V_{O_2}=n_{O_2}.22,4=0,05.22,4=1,12\left(l\right)\)

b. PTHH: \(3Fe+2O_2\xrightarrow[]{t^o}Fe_3O_4\)

\(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)

Ta có: \(\dfrac{1}{n_{O_2}}=\dfrac{1}{0,05}\)

\(\dfrac{1}{n_{Fe}}=\dfrac{1}{0,1}\)

\(\Rightarrow\dfrac{1}{n_{O_2}}>\dfrac{1}{n_{Fe}}\)

Vậy Fe dư

Theo PTHH: \(n_{Fe_3O_4}=\dfrac{0,1.1}{3}=\dfrac{1}{30}\left(mol\right)\)

\(\Rightarrow m_{Fe_3O_4}=n_{Fe_3O_4}.M_{Fe_3O_4}=\dfrac{1}{30}.232\approx7,73g\)

Bài 1 : 

a. \(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\)

\(n_{O_2}=\dfrac{16}{32}=0,5\left(mol\right)\)

b. PTHH : 4Al + 3O₂ -t^o> 2Al₂O₃

                 0,4       0,3       0,2

Xét tỉ lệ : \(\dfrac{0,4}{4}< \dfrac{0,5}{3}\) => Al đủ , O₂ dư

\(m_{O_2\left(dư\right)}=\left(0,5-0,3\right).32=6,4\left(g\right)\)

c. \(m_{Al_2O_3}=0,2.102=20,4\left(g\right)\)

Bài 2: