\(a,n_{Na}=\dfrac{2,3}{23}=0,1\left(mol\right);n_{O_2}=\dfrac{0,896}{22,4}=0,04\left(mol\right)\\ a,PTHH:4Na+O_2\rightarrow2Na_2O\\ Vì:\dfrac{0,1}{4}< \dfrac{0,04}{1}\Rightarrow O_2dư\\ n_{O_2\left(dư\right)}=0,04-\dfrac{0,1}{4}=0,015\left(mol\right)\\ \Rightarrow m_{O_2\left(dư\right)}=0,015.32=0,48\left(g\right)\\ b,C1:n_{Na_2O}=\dfrac{2}{4}.n_{Na}=\dfrac{2}{4}.0,1=0,05\left(mol\right)\\ \Rightarrow m_{Na_2O}=0,05.62=3,1\left(g\right)\\ C2:ĐLBTKL:m_{Na_2O}=m_{Na}+m_{O_2\left(bđ\right)}-m_{O_2\left(dư\right)}=2,3+0,04.32-0,48=3,1\left(g\right)\)

a. \(n_{Na}=\dfrac{2,3}{23}=0,1\left(mol\right)\)

\(n_{O_2}=\dfrac{0,896}{22,4}=0,04\left(mol\right)\)

PTHH : 4Na + O₂ -t^o> 2Na₂O

             0,1    0,025      0,05

Xét tỉ lệ : \(\dfrac{0,1}{4}< \dfrac{0,04}{1}\) => Na đủ , O₂ dư

\(m_{O_2\left(dư\right)}=\left(0,04-0,025\right).32=0,48\left(g\right)\)

b. Cách 1 : \(m_{Na_2O}=0,05.62=3,1\left(g\right)\)

Cách 2 : \(m_{Na}=0,1.23=2,3\left(g\right)\)

\(m_{O_2}=0,025.32=0,8\left(g\right)\)

Theo ĐLBTKL: 

\(m_{Na}+m_{O_2}=m_{Na_2O}\\ \Rightarrow2,3+0,8=3,1\left(g\right)\)

a,pthh: \(4Na+O_2\underrightarrow{t^o}2Na_2O\)

\(nNa=\dfrac{2,3}{23}=0,1\left(mol\right)\)

\(nO_2=0,896:22,4=0,04\left(mol\right)\)

Xét tỉ lệ : \(\dfrac{nNa}{4}< \dfrac{nO_2}{1}\) ( \(\dfrac{0,1}{4}< \dfrac{0,04}{1}\)) => Oxi dư

\(\Rightarrow nO_{2\left(dư\right)}=0,04-0,025=0,015\left(mol\right)\)

\(nO_{2\left(dư\right)}=0,015.32=0,48\left(g\right)\)

b, do oxi dư nên lấy số mol của natri làm chuẩn.

 \(nNa_2O=0,05\left(mol\right)\)

\(mNa_2O=0,05.\left(23.2+16\right)=3,1\left(gam\right)\)

c2: \(mO_{2\left(đủ\right)}=\) 0,8(gam) 

BTKL : mNa+mO2=mNa2O

<=> 2,3+ 0,8= mNa2O

=>mNa2O= 3,1 (gam)

 C_{nguyên chất} = (100%-10%).1000 = 900 (g)

\(n_C=\dfrac{900}{12}=75\left(mol\right)\)

PTHH: C + O₂ ---t^o→ CO₂

Mol:    75    75

\(V_{O_2}=75.22,4=1680\left(l\right)\)

\(m_{CO_2}=75.44=3300\left(g\right)\)

$a) CH_4 + 2O_2 \xrightarrow{t^o} CO_2 + 2H_2O$

b) $n_{CH_4} = \dfrac{3,92}{22,4} = 0,175(mol)$

$n_{O_2} = \dfrac{3,84}{32} = 0,12(mol)$

Ta thấy : $n_{CH_4} : 1 > n_{O_2} : 2$ nên $CH_4$ dư

$n_{CH_4\ pư} = \dfrac{1}{2}n_{O_2} = 0,06(mol)$
$\Rightarrow m_{CH_4\ dư} = (0,175 - 0,06).16 = 1,84(gam)$

c) $2NaOH + CO_2 \to Na_2CO_3 + H_2O$

Theo PTHH :

$n_{Na_2CO_3} = n_{CO_2} = \dfrac{1}{2}n_{CH_4} = 0,06(mol)$
$m_{Na_2CO_3} = 0,06.106 = 6,36(gam)$

a. \(n_P=\dfrac{12.4}{31}=0,4\left(mol\right)\)

\(n_{O_2}=\dfrac{67.2}{22,4}=3\left(mol\right)\)

Ta thấy : 0,4 < 3 => P đủ , O₂ dư

PTHH : 4P + 5O₂ -----t^o-----> 2P₂O₅

            0,4     0,5                      0,2

b. \(m_{P_2O_5}=0,2.142=28,4\left(g\right)\)

nP = 6.2/31 = 0.2 (mol) 

nO2 = 6.72/22.4 = 0.3 (mol) 

4P + 5O2 -to-> 2P2O5 

0.2___0.25_____0.1

mO2 dư = ( 0.3 - 0.25) * 32 = 1.6(g) 

mP2O5 = 0.1*142 = 14.2 (g) 

Ta có: \(n_P=\dfrac{6.2}{31}=0.29mol\)

\(n_{O_2}=\dfrac{6.72}{22.4}=0.3mol\)

PTHH:

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

ta có:

\(\left\{{}\begin{matrix}\dfrac{n_{P\left(bra\right)}}{nP_{\left(pthh\right)}}=\dfrac{0.2}{4}=0.05\\\dfrac{n_{O_2\left(bra\right)}}{n_{O_2}\left(pthh\right)}=\dfrac{0.3}{5}=0.06\end{matrix}\right.\)

=> \(O_2\) dư 

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

4   ----------->2                

0.2---------->0.1=n_P2O5

=>\(m_{P_2O_5}=142.0.1=14.2\left(g\right)\)

a) $n_P = \dfrac{12,4}{31} = 0,4(mol) ; n_{O_2} = \dfrac{13,44}{22,4} = 0,6(mol)$

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

Ta thấy : 

$n_P : 4 < n_{O_2} : 5$ nên $O_2$ dư

 Điphotpho pentaoxit được tạo thành

$n_{P_2O_5} = \dfrac{1}{2}n_P = 0,2(mol)$
$m_{P_2O_5} = 0,2.142 = 28,4(gam)$

Số mol của oxi tham gia phản ứng:

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

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

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