\(n_{KMnO4}=\dfrac{15,8}{158}=0,1\left(mol\right)\)

a) Pt : \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2|\)

                   2                   1            1         1

                  0,1                                          0,05

b) \(n_{O2}=\dfrac{0,1.1}{2}=0,05\left(mol\right)\)

\(V_{O2\left(dktc\right)}=0,05.22,4=1,12\left(l\right)\)

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

Pt : \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4|\)

            3         2            1

          0,1       0,05       0,025      

Lập tỉ số so sánh : \(\dfrac{0,1}{3}>\dfrac{0,05}{2}\)

                     ⇒ Fe dư , O₂ phản ứng hết

                     ⇒ Tính toán dựa vào số mol của O₂

\(n_{Fe3O4}=\dfrac{0,05.1}{2}=0,025\left(mol\right)\)

⇒ \(m_{Fe3O4}=0,025.232=5,8\left(g\right)\)

 Chúc bạn học tốt

\(n_{C_2H_5OH}=\dfrac{13,8}{46}=0,3mol\)

\(C_2H_5OH+3O_2\rightarrow2CO_2+3H_2O\)

     0,3          0,9          0,6                   ( mol )

\(V_{CO_2}=0,6.22,4=13,44l\)

\(V_{kk}=\left(0,9.22,4\right).5=100,8l\)

C2H5OH+3O2-to>2CO2+3H2O

0,3------------0,9-----------0,6

n C2H5OH=0,3 mol

=>VCO2=0,6.22,4=13,44l

=>VO2=0,9.22,4.5=100,8l

\(n_{C_2H_5OH}=\dfrac{13,8}{46}=0,3mol\)

\(C_2H_5OH+3O_2\underrightarrow{t^o}2CO_2+3H_2O\)

0,3               0,9      0,6

\(V_{CO_2}=0,6\cdot22,4=13,44l\)          

\(V_{O_2}=0,9\cdot22,4=20,16l\)

\(V_{kk}=5V_{O_2}=5\cdot20,16=100,8l\)

\(a) 4Al + 3O_2 \xrightarrow{t^o} 2Al_2O_3\\ n_{Al} = \dfrac{5,4}{27} = 0,2(mol)\\ n_{Al_2O_3} = \dfrac{1}{2}n_{Al} = 0,1(mol) \Rightarrow m_{Al_2O_3} = 0,1.102 = 10,2(gam)\\ b) n_{O_2} = \dfrac{3}{4}n_{Al} = 0,15(mol)\\ 2KMnO_4 \xrightarrow{t^o} K_2MnO_4 + MnO_2 + O_2\\ n_{KMnO_4} = 2n_{O_2} = 0,3(mol) \Rightarrow m_{KMnO_4} = 0,3.158 = 47,4(gam)\)

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: \(n_{Al_2O_3}=\dfrac{1}{2}n_{Al}=0,1\left(mol\right)\)

\(\Rightarrow m_{Al_2O_3}=0,1.102=10,2\left(g\right)\)

b, Theo PT:  \(n_{O_2}=\dfrac{3}{4}n_{Al}=0,15\left(mol\right)\)

PT: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)

Theo PT: \(n_{KMnO_4}=2n_{O_2}=0,3\left(mol\right)\)

\(\Rightarrow m_{KMnO_4}=0,2.158=47,4\left(g\right)\)

Bạn tham khảo nhé!

a) nFe= 0,25(mol)

PTHH: Fe + H2SO4 -> FeSO4 + H2

0,25______0,25______0,25__0,25(mol)

b) V(H2,đktc)=0,25.22,4=5,6(l)

c) mH2SO4= 0,25.98= 24,5(g)

Lời giải "chi tiết"

PTHH: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)

Ta có: \(n_{Fe}=\dfrac{14}{56}=0,25\left(mol\right)=n_{H_2SO_4}=n_{H_2}\)

\(\Rightarrow\left\{{}\begin{matrix}m_{H_2SO_4}=0,25\cdot98=24,5\left(g\right)\\V_{H_2}=0,25\cdot22,4=5,6\left(l\right)\end{matrix}\right.\)

a,PTHH:

=0,25(mol)

Theo pt: nH2=nFe=0,25(mol)

⇒VH2=0,25.22,4=5,6(l)

c, Theo pt: nH2SO4=nFe=0,25(mol)

⇒mH2SO4=0,25.98=24,5(g)

a/ Ta có: \(n_{Mg}=\dfrac{4.8}{24}=0.2\left(mol\right)\)

PTHH: 

\(2Mg+O_2\underrightarrow{t^o}2MgO\)

2          1

0.2       x

\(=>x=\dfrac{0.2\cdot1}{2}=0.1=n_{O_2}\)  

\(=>V_{O_2\left(đktc\right)}=0.1\cdot22.4=2.24\left(l\right)\)

b/ \(2Mg+O_2\underrightarrow{t^o}2MgO\)

     2                  2

     0.2               y

\(=>y=\left(0.2\cdot2\right):2=0.2=n_{MgO}\)

\(=>m_{MgO}=0.2\cdot\left(24+16\right)=8\left(g\right)\)

n_Mg=\(\dfrac{m}{M}\)=\(\dfrac{4.8}{24}\)=0.2(mol)

PTHH: 2Mg  + O₂ \(\rightarrow\)2MgO

            0.2  \(\rightarrow\) 0.1 \(\rightarrow\)  0.2  (mol)

a) \(\Rightarrow\)V_{O\(_2\)}=n.22,4=0.1.22.4=2.24(l)

b)\(\Rightarrow\)m_MgO=n.M=0.2.(24+16)=8(g)

--chúc bạn học tốt nha--

\(a) CH_4 + 2O_2 \xrightarrow{t^o} CO_2 + H_2O\\ 2C_2H_2 + 5O_2 \xrightarrow{t^o} 4CO_2 + 2H_2O\\ b) n_{CH_4} = a(mol) ; n_{C_2H_2} = b(mol)\\ \Rightarrow a + b = \dfrac{6,72}{22,4} = 0,3(1)\\ n_{O_2} = 2a + \dfrac{5}{2}b = \dfrac{22,4}{32} = 0,7(2)\\ (1)(2) \Rightarrow a = 0,1 ; b = 0,2\\ \%V_{CH_4} = \dfrac{0,1.22,4}{6,72}.100\% = 33,33\%\\ \%V_{C_2H_2} = 100\% - 33,33\% = 66,67\%\)

a, PT: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)

\(2C_2H_2+5O_2\underrightarrow{t^o}4CO_2+2H_2O\)

b, Giả sử: \(\left\{{}\begin{matrix}n_{CH_4}=x\left(mol\right)\\n_{C_2H_2}=y\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow x+y=\dfrac{6,72}{22,4}=0,3\left(mol\right)\left(1\right)\)

Ta có: \(n_{O_2}=\dfrac{22,4}{32}=0,7\left(mol\right)\)

Theo PT: \(n_{O_2}=2n_{CH_4}+\dfrac{5}{2}n_{C_2H_2}=2x+\dfrac{5}{2}y\left(mol\right)\)

\(\Rightarrow2x+\dfrac{5}{2}y=0,7\left(2\right)\)

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

\(\Rightarrow\left\{{}\begin{matrix}\%V_{CH_4}=\dfrac{0,1}{0,3}.100\%\approx33,33\%\\\%V_{C_2H_2}\approx66,67\%\end{matrix}\right.\)

Bạn tham khảo nhé!

\(n_{Al}=\dfrac{5,4}{27}=0,2mol\)

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

0,2      0,15    0,1

\(m_{Al_2O_3}=0,1\cdot102=10,2g\)

\(2KClO_3\underrightarrow{t^o}2KCl+3O_2\)

0,1                            0,15

\(m_{KClO_3}=0,1\cdot122,5=12,25g\)

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

\(n_{Al}=5,4:27=0,2\left(mol\right)\)

\(\Rightarrow n_{Al_2O_3}=0,2.2:4=0,1\left(mol\right);n_{O_2}=0,2.3:4=0,15\left(mol\right)\)

\(m_{Al_2O_3}=0,1.102=10,2\left(g\right)\)

b)\(PTHH:2KClO_3\underrightarrow{t^o}2KCl+3O_2\)

\(n_{O_2}=0,15\left(mol\right)\)(câu a)

\(\Rightarrow n_{KClO_3}=0,15.2:3=0,1\left(mol\right)\)

\(m_{KClO_3}=0,1.123,5=12,35\left(g\right)\)

\(n_{Na_2O}=\dfrac{124}{62}=2\left(mol\right)\)

PTHH: 4Na + O₂ --t^o--> 2Na₂O

                       1<----------2

=> m_O2 = 1.32 = 32 (g)

BTKLg

=>m O2=124-62=62g

Xin lỗi. Xoi là xoi, 18h là 18 g

1) 2Cu+O₂=t^o=>2CuO

\(n_{Cu}=\frac{6,4}{64}=0,1mol\)

\(n_{O_2}=2.n_{O_2}=2.0,1=0,2mol\)

\(V_{O_2}=0,2.22,4=4,48l\)

\(V_{kk}=4,48.5=22,4l\)

b) \(2KMnO_4\rightarrow K_2MnO_4+MnO_2+O_2\)

\(n_{KMnO_4}=2.n_{O_2}=2.0,2=0,4mol\)

\(m_{KMnO_4}=0,4.158=63,2g\)

c) 2Mg+O₂->2MgO

Bài này tự tính luôn nha, dễ mà