a)

\(n_{Mg} = \dfrac{4,8}{24} = 0,2(mol)\\ n_{O_2} = \dfrac{3,36}{22,4}= 0,15(mol)\\ 2Mg + O_2 \xrightarrow{t^o} 2MgO\)

Ta thấy : 

\( \dfrac{n_{Mg}}{2} = 0,1 < n_{O_2} = 0,15 \) nên O₂ dư.

\(n_{O_2\ pư} = \dfrac{n_{Mg}}{2} = 0,1(mol)\\ m_{O_2\ dư} = (0,15-0,1).32 = 1,6(gam)\\ V_{O_2\ dư} = (0,15-0,1).22,4 = 1,12(lít)\)

b)

\(n_{MgO} = n_{Mg} = 0,2\ mol\\ \Rightarrow m_{MgO} = 0,2.40 = 8\ gam\)

nO2 = 3,36 : 22,4 = 0,15 (mol) 
pthh : 2Mg + O2 -t--> 2MgO
         0,3<----0,15---> 0,3 (mol) 
=> mMg= 0,3 . 24 = 7,2 (g) 
=> mMgO = 0,3 . 40 =12 (g) 
pthh : 2KMnO4 -t--> K2MnO4 + MnO2 + O2 
           0,3<-------------------------------------0,15 (mol) 
=> mKMnO4 = 0,3 . 158 = 47,4 (g) 

\(n_{Cu}=\dfrac{32}{64}=0,5\left(mol\right);n_{O_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\\ PTHH:2Cu+O_2\rightarrow2CuO\\ TL:....2.....1.....2\\ BR:....0,2......0,1.....0,2\left(mol\right)\)

Vì \(\dfrac{n_{Cu}}{2}>\dfrac{n_{O_2}}{1}\) nên sau p/ứ Cu dư, O₂ hết

\(a,m_{CuO}=0,2\cdot80=16\left(g\right)\)

\(m_{HCl}=\dfrac{200\cdot14,6\%}{100\%}=29,2\left(g\right)\\ \Rightarrow n_{HCl}=\dfrac{29,2}{36,5}=0,8\left(mol\right)\\ PTHH:CuO+2HCl\rightarrow CuCl_2+H_2O\\ TL:....1.....2.....1.....1\\ BR:....0,2.....0,4.....0,2.....0,2\left(mol\right)\)

Vì \(\dfrac{n_{CuO}}{1}< \dfrac{n_{HCl}}{2}\) nên sau p/ứ HCl dư, CuO hết

\(\Rightarrow n_{HCl\left(dư\right)}=0,8-0,4=0,4\left(mol\right)\\ \Rightarrow m_{HCl\left(dư\right)}=14,6\left(g\right)\)

\(m_{CuCl_2}=0,2\cdot135=27\left(g\right)\\ m_{HCl}=0,4\cdot36,5=14,6\left(g\right)\\ m_{CuO}=16\left(g\right)\\ m_{H_2O}=0,2\cdot18=3,6\left(g\right)\\ \Rightarrow m_{dd_{CuCl_2}}=16+14,6-3,6=27\left(g\right)\)

Vậy \(C\%_{dd_{CuCl_2}}=\dfrac{27}{200}\cdot100\%=13,5\%\)

a. \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)

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

PTHH : 2Mg + O₂ -> 2MgO

               0,2      0,1       0,2

Xét tỉ lệ : \(\dfrac{0,2}{2}< \dfrac{0,3}{1}\) => Mg đủ , O₂ dư

\(m_{O_2\left(dư\right)}=\left(0,3-0,1\right).32=6,4\left(g\right)\)

b) \(m_{MgO}=0,2.40=8\left(g\right)\)

nP=\(\dfrac{62}{31}\)=0,2(mol)

nO2=\(\dfrac{7,84}{22,4}\)=0,35(mol)

PTHH:4P+5O2to→2P2O5

tpứ:    0,2     0,35     

pứ:     0,2     0,25     0,1

spứ:     0     0,1         0,1

a)chất còn dư là oxi

mO2dư=0,1.32=3,2(g)

b)mP2O5=n.M=0,1.142=14,2(g)

\(a.n_P=0,2\left(mol\right);n_{O_2}=0,35\left(mol\right)\\ 4P+5O_2-^{t^o}\rightarrow2P_2O_5\\ LTL:\dfrac{0,2}{4}< \dfrac{0,35}{5}\\ \Rightarrow SauphảnứngO_2dư\\ n_{O_2\left(pứ\right)}=\dfrac{5}{4}n_P=0,25\left(mol\right)\\ \Rightarrow m_{P\left(dư\right)}=\left(0,35-0,25\right).32=3,2\left(g\right)\\ b.n_{P_2O_5}=\dfrac{1}{2}n_P=0,1\left(mol\right)\\ \Rightarrow m_{P_2O_5}=0,1.142=14,2\left(g\right)\)

\(a,n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\\ n_{O_2}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\)

PTHH: 4Al + 3O₂ --t^o--> 2Al₂O₃

b, LTL: \(\dfrac{0,4}{4}>\dfrac{0,6}{3}\) => O₂ dư

Theo pthh: \(\left\{{}\begin{matrix}n_{O_2\left(pư\right)}=\dfrac{3}{4}n_{Al}=\dfrac{3}{4}.0,4=0,3\left(mol\right)\\n_{Al_2O_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}.0,4=0,2\left(mol\right)\end{matrix}\right.\)

=> V_{O2 (dư)} = (0,6 - 0,3).22,4 = 6,72 (l)

c, m_Al2O3 = 0,2.102 = 20,4 (g)

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

\(n_{O_2}=\dfrac{13,44}{22,4}=0,6mol\)

    \(4Al+3O_2\rightarrow\left(t^o\right)2Al_2O_3\)

Xét: \(\dfrac{0,4}{4}\) < \(\dfrac{0,6}{3}\)                  ( mol )

         0,4     0,3            0,2   ( mol )

Chất dư là O₂

\(m_{O_2\left(dư\right)}=\left(0,6-0,3\right).32=9,6g\)

\(m_{Al_2O_3}=0,2.102=20,4g\)

PTHH:

2KMnO₄ -to> K₂MnO₄ + MnO₂ + O₂

0,2------------------------------------------0,1

n KMnO4=\(\dfrac{31,6}{158}\)=0,2 mol

=>VO2=0,1.22,4=2,24l

b)2Mg+O₂-to>2MgO

     0,2----0,1----0,2

n Mg=\(\dfrac{7,2}{24}\)=0,3 mol

=>Mg dư :0,1 mol

=>mMg=0,1.24=2,4g

=>m MgO=0,2.40=8g

\(PTHH:4Al+3O_2->2Al_2O_3\)

BĐ          0,4      0,27                     (mol)

PU        0,36---->0,27---->0,18         (mol) 

CL          0,04---->0------>0,18     (mol)

b)

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

\(n_{O_2}=\dfrac{V}{22,4}=\dfrac{6,048}{22,4}=0,27\left(mol\right)\)

\(\dfrac{n_{Al}}{4}>\dfrac{n_{O_2}}{3}\left(\dfrac{0,4}{4}>\dfrac{0,27}{3}\right)\)

=> Al dư, O2 hết (tính theo O2)

\(m_{Al}=n\cdot M=0,04\cdot27=1,08\left(g\right)\)

c)

\(m_{Al_2O_3}=n\cdot M=0,18\cdot\left(27\cdot2+16\cdot3\right)=18,36\left(g\right)\)

a, PT: \(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)

b, Ta có: \(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\)

\(n_{O_2}=\dfrac{6,048}{22,4}=0,27\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,4}{4}>\dfrac{0,27}{3}\), ta được Al dư.

Theo PT: \(n_{Al\left(pư\right)}=\dfrac{4}{3}n_{O_2}=0,36\left(mol\right)\)

\(\Rightarrow n_{Al\left(dư\right)}=0,4-0,36=0,04\left(mol\right)\)

\(\Rightarrow m_{Al\left(dư\right)}=0,04.27=1,08\left(g\right)\)

c, Theo PT: \(n_{Al_2O_3}=\dfrac{2}{3}n_{Al}=0,18\left(mol\right)\)

\(\Rightarrow m_{Al_2O_3}=0,18.102=18,36\left(g\right)\)