B

B

a) 4P + 5O₂ --t^o--> 2P₂O₅

b) \(n_{P_2O_5}=\dfrac{34,08}{142}=0,24\left(mol\right)\)

4P + 5O₂ --t^o--> 2P₂O₅

0,48<-0,6<------0,24

=> m_O2 = 0,6.32 = 19,2 (g)

c)

C1: m_P = 0,48.31 = 14,88(g)

C2:

Theo ĐLBTKL: m_P + m_O2 = m_P2O5

=> m_P = 34,08-19,2 = 14,88(g)

d)

V_O2 = 0,6.22,4 = 13,44 (l)

=> V_kk = 13,44 :20% = 67,2 (l)

\(4P+5O_2--t^0\rightarrow2P_2O_5\)

Chọn B

B

\(n_{O_2\left(đktc\right)}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\ 4P+5O_2\underrightarrow{^{to}}2P_2O_5\\ 0,12........0,15.........0,06\left(mol\right)\\ m_P=0,12.31=3,72\left(g\right)\)

Ta có: \(n_{O_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

PTHH: 4P + 5O₂ ---t^o---> 2P₂O₅.

Theo PT: n_P = \(\dfrac{4}{5}.n_{O_2}=\dfrac{4}{5}.0,15=0,12\left(mol\right)\)

=> m_P = 31 . 0,12 = 3,72(g)

\(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\\ n_{O_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\\ PTHH:4P+5O_2\underrightarrow{t^o}2P_2O_5\\ LTL:\dfrac{0,2}{4}< \dfrac{0,4}{5}\Rightarrow O_2dư\)

\(n_{O_2\left(pư\right)}=\dfrac{5}{4}n_P=\dfrac{5}{4}.0,2=0,25\left(mol\right)\\ n_{O_2\left(dư\right)}=0,4-0,25=0,15\left(mol\right)\)

\(n_{P_2O_5\left(lt\right)}=\dfrac{1}{2}n_P=\dfrac{1}{2}.0,2=0,1\left(mol\right)\\ m_{P_2O_5\left(lt\right)}=0,1.142=14,2\left(g\right)\\ m_{P_2O_5\left(tt\right)}=0,1.142.80\%=11,36\left(g\right)\)

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

\(b.n_{O_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)

\(\Rightarrow n_P=\dfrac{0,5}{5}.4=0,4\left(mol\right)\\ \Rightarrow m_P=0,4.31=12,4\left(g\right)\)

\(m_{O_2}=0,5.32=16\left(g\right)\\ \Rightarrow m_P+m_{O_2}=m_{P_2O_5}\\ m_{P_2O_5}=24,8+16=40,8\left(g\right)\)

a) \(PTHH:4P+5O_2\) → \(2P_2O_5\)

b) \(n_{O_2}=\dfrac{V_{O_2\left(đktc\right)}}{22,4}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)

Theo PTHH:

⇒ \(n_P=\dfrac{4}{5}.n_{O_2}=\dfrac{4}{5}.0,5=0,4\left(mol\right)\)

⇒ \(m_P=n.M=0,4.31=12,4\left(g\right)\)

c) Theo định luật bảo toàn khối lượng

⇒ \(m_P+m_{O_2}=m_{P_2O_5}\)

⇒ \(m_{P_2O_5}=?\)

a) 4P + 5O2 -> 2P2O5

0,4mol<-0,5mol->0,2mol(1)

0,8mol              ->0,4mol(2)

nO2=11,2/22,4=0,5mol

nP=24,8/31=0,8mol

b)mP=0,4x31=12,4g

c)mP2O5=0,4x142=56,8

\(n_P=\dfrac{3.1}{31}=0.1\left(mol\right)\)

\(4P+5O_2\underrightarrow{^{^{t^0}}}2P_2O_5\)

\(0.1.......0.125.....0.05\)

\(V_{O_2}=0.125\cdot22.4=2.8\left(l\right)\)

\(m_{P_2O_5}=0.05\cdot142=7.1\left(g\right)\)

n_P= 3,1 / 31 =0,1 mol

          2P +   5/2O₂ → P₂O₅

           0,1     0,125       0,05      mol

V_O2=0,125.22,4=2,8 l

b) mP₂O₅=0,05.142=7,1 g

C9:

nP = 6,2/31 = 0,2 (mol)

nO2 = 6,4/32 = 0,2 (mol)

PTHH: 4P + 5O2 -> (t°) 2P2O5

LTL: 0,2/4 > 0,2/5 => P dư

nP (p/ư) = 0,2/5 . 4 = 0,16 (mol)

nP (dư) = 0,2 - 0,16 = 0,04 (mol)

nP2O5 = 0,2/5 . 2 = 0,08 (mol)

mP2O5 = 0,08 . 142 = 11,36 (g)

C10: 

Áp dụng ĐLBTKL, ta có:

mR + mO2 = mRO

=> mO2 = 21,6 - 16,8 = 4,8 (g(

=> nO2 = 4,8/32 = 0,15 (mol)

PTHH: 2R + O2 -> (t°) 2RO

nR = 0,15 . 2 = 0,3 (mol)

M(R) = 16,8/0,3 = 56 (g/mol(

=> R là Fe

Bài 1:

\(n_{O_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

\(4P+5O_2\rightarrow2P_2O_5\)

0,24.... 0,3 .... 0,12 (mol)

\(m_P=0,24.31=7,44\left(g\right)\)

\(m_{P_2O_5}=0,12.142=17,04\left(g\right)\)

Bài 2:

\(n_{Al}=\dfrac{21,6}{27}=0,8\left(mol\right)\)

\(4Al+3O_2\rightarrow2Al_2O_3\)

0,8 .... 0,6 ...... 0,4 (mol) 

\(m_{Al_2O_3}=0,4.102=40,8\left(g\right)\)

\(V_{O_2}=0,6.22,4=13,44\left(l\right)\)