Bài 14

\(n_{O_2}=\dfrac{1.4}{22,4}=0,0625\left(mol\right)\)

\(n_P=\dfrac{2.5}{31}=0,0806451\left(mol\right)\)

4P  +  5O₂ ----t^o--->2P₂O₅

Xét tỉ lệ : \(\dfrac{0.0625}{5}< \dfrac{0.0806451}{4}\)

=> P ko cháy hết 

bài 15

\(n_{O_2}=\dfrac{3.36}{22,4}=0,15\left(mol\right)\)

Gọi n_Fe = a ( mol ) và n_S = b (mol )

PTHH : 

S + O₂ ---t^o---> SO₂

3Fe + 2O₂ ----t^o----> Fe₃O₄

Ta có 32b + 56a= 100

Theo PT : n_S = n_O2 = b (mol)

Theo PT : n_O2 = 2/3 n_Fe = 2/3a ( mol)

=> 2/3a + b = 1,5 

Từ những điều trên  \(\left[{}\begin{matrix}56a+32b=100\\\dfrac{2}{3}a+b=1,5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}a=1,5\left(mol\right)\\b=0,5\left(mol\right)\end{matrix}\right.\)

\(m_{Fe}=1,5.56=84\left(g\right)\)

\(m_S=0,5.32=16\left(g\right)\)

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, PT: \(C+O_2\underrightarrow{t^o}CO_2\)

\(S+O_2\underrightarrow{t^o}SO_2\)

b, Giả sử: \(\left\{{}\begin{matrix}n_C=x\left(mol\right)\\n_S=y\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow12x+32y=5,6\left(1\right)\)

Ta có: \(n_{O_2}=\dfrac{9,6}{32}=0,3\left(mol\right)\)

Theo PT: \(\Sigma n_{O_2}=n_C+n_S=x+y\left(mol\right)\)

\(\Rightarrow x+y=0,3\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,1\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}m_C=0,2.12=2,4\left(g\right)\\m_S=0,1.32=3,2\left(g\right)\end{matrix}\right.\)

c, Ta có: \(\left\{{}\begin{matrix}\%m_C=\dfrac{2,4}{5,6}.100\%\approx42,9\%\\\%m_S\approx57,1\%\end{matrix}\right.\)

d, Phần này đề yêu cầu tính theo khối lượng mol hả bạn?

9,2 hay 9,6 oxxi vậy

\(n_{O2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

Pt : \(S+O_2\underrightarrow{t^o}SO_2|\)

      1      1         1

    0,15 0,15     0,15

a) \(n_S=\dfrac{0,15.1}{1}=0,15\left(mol\right)\)

⇒ \(m_S=0,15.32=4,8\left(g\right)\)

b) \(n_{SO2}=\dfrac{0,15.1}{1}=0,15\left(mol\right)\)

\(V_{SO2\left(dktc\right)}=0,15.22,4=3,36\left(l\right)\)

 Chúc bạn học tốt

Gọi số mol C, S là a, b

=> 12a + 32b = 7,68

PTHH: C + O₂ --t^o--> CO₂

_____a--------------->a

S + O₂ --t^o--> SO₂

b--------------->b

=> a + b = \(\dfrac{9,856}{22,4}=0,44\)

=> a = 0,32; b = 0,12

=> \(\left\{{}\begin{matrix}\%C=\dfrac{0,32.12}{7,68}.100\%=50\%\\\%S=\dfrac{0,12.32}{7,68}.100\%=50\%\end{matrix}\right.\)

\(n_{hhkhí}=\dfrac{16,8}{22,4}=0,75\left(mol\right)\)

Gọi \(n_{SO_2}=a\left(mol\right)\left(0< a< 0,75\right)\)

\(\rightarrow n_{O_2\left(dư\right)}=0,75-b\left(mol\right)\)

Ta có: \(\dfrac{64a+32\left(0,75-a\right)}{0,75}=\dfrac{33,6}{1}=33,6\left(\dfrac{g}{mol}\right)\)

\(\rightarrow a=0,0375\left(mol\right)\)

\(\rightarrow\left\{{}\begin{matrix}\%V_{SO_2}=\dfrac{0,0375}{0,75}=5\%\\\%V_{O_2\left(dư\right)}=100\%-5\%=95\%\end{matrix}\right.\)

gọi x, y là số mol của C, S ta có

12*C + 32*S = 4.4(*)

PTHH

C + O2 ==> CO2

S + O2 ==> SO2

==> x + y =4.48/22.4 = 0.2 (**)

từ *, ** ==> x= 0.1 ==> n_C =n_CO2 =0.1 mol ==> m_CO2 =44*0.1 =4.4 g

==> y= 0.1 ==> n_S =n_SO2= 0.1 mol ==> m_SO2 =64*0.1 =6.4 g