Bài 1.

a.\(n_{KClO_3}=\dfrac{49}{122,5}=0,4mol\)

\(2KClO_3\rightarrow\left(t^o,MnO_2\right)2KCl+3O_2\)

   0,4                                            0,6     ( mol )

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

b.\(n_P=\dfrac{12,4}{31}=0,4mol\)

\(4P+5O_2\rightarrow\left(t^o\right)2P_2O_5\)

\(\dfrac{0,4}{4}\)< \(\dfrac{0,6}{5}\)                          ( mol )

0,4                           0,2            ( mol )

Chất dư là O2

\(m_{O_2\left(dư\right)}=0,6-\left(\dfrac{0,4.5}{4}\right)=0,1mol\)

\(m_{P_2O_5}=0,2.142=28,4g\)

Bài 2.

a.\(n_{KMnO_4}=\dfrac{126,4}{158}=0,8mol\)

\(2KMnO_4\rightarrow\left(t^o\right)K_2MnO_4+MnO_2+O_2\)

    0,8                                                        0,4  ( mol )

\(V_{O_2}=0,4.22,4=8,96l\)

b.\(n_P=\dfrac{12,4}{31}=0,4mol\)

\(4P+5O_2\rightarrow\left(t^o\right)2P_2O_5\)

\(\dfrac{0,4}{4}\) > \(\dfrac{0,4}{5}\)                      ( mol )

            0,4              0,16      ( mol )

Chất dư là P

\(n_{P\left(dư\right)}=0,4-\left(\dfrac{0,4.4}{5}\right)=0,08mol\)

\(m_{P_2O_5}=0,16.142=22,72g\)

3. a) M_O2/M_N2 = 32/28 = 8/7

b) M_O2/M_CO = 32/28 = 8/7

c) M_O2/M_kk = 32/29

1 tính khối lượng của

a) 0.5 mol Fe2O3

\(M_{Fe_2O_3}=2\times56+3\times16=160\) (g/mol)

\(m_{Fe_2O_3}=n_{Fe_2O_3}\times M_{Fe_2O_3}=0,5\times112=56\left(g\right)\)

b) 0,15 mol CO2

\(M_{CO_2}=1\times12+2\times16=44\) (g/mol)

\(m_{CO_2}=n_{CO_2}\times M_{CO_2}=0,15\times44=6,6\left(g\right)\)

c) 5,6 lít O2 ( điều kiện tiêu chuẩn )

\(n_{O_2}=\frac{V_{O_2}}{22,4}=\frac{5,6}{22,4}=0,25\left(mol\right)\)

\(M_{O_2}=2\times16=32\) (g/mol)

\(m_{O_2}=n_{O_2}\times M_{O_2}=0,25\times32=8\left(g\right)\)

d) 8,96 lít H2 ( điều kiện tiêu chuẩn)

\(n_{H_2}=\frac{V_{H_2}}{22,4}=\frac{8,96}{22,4}=0,4\left(mol\right)\)

\(M_{H_2}=2\times1=2\) (g/mol)

\(m_{H_2}=n_{H_2}\times M_{H_2}=0,4\times2=0,8\left(g\right)\)

2 tính thể tích ( điều kiện tiêu chuẩn)

a) 0,125 mol Cl2

\(V_{Cl_2}=22,4\times n_{Cl_2}=22,4\times0,125=2,8\left(l\right)\)

b) 2,5 mol CH4

\(V_{CH_4}=22,4\times n_{CH_4}=22,4\times2,5=56\left(l\right)\)

c) 6,4 gam 02

\(M_{O_2}=2\times16=32\) (g/mol)

\(n_{O_2}=\frac{m_{O_2}}{M_{O_2}}=\frac{6,4}{32}=0,2\left(mol\right)\)

\(V_{O_2}=22,4\times n_{O_2}=22,4\times0,2=4,48\left(l\right)\)

d) 5,6 gam N2

\(M_{N_2}=2\times14=28\) (g/mol)

\(n_{N_2}=\frac{m_{N_2}}{M_{N_2}}=\frac{5,6}{28}=0,2\left(mol\right)\)

\(V_{N_2}=22,4\times n_{N_2}=22,4\times0,2=4,48\left(l\right)\)

3 tính tỉ khối của khí O2 so với

a) khí N2

\(d_{O_2;N_2}=\frac{M_{O_2}}{M_{N_2}}=\frac{2\times16}{2\times14}=\frac{8}{7}\)

b) khí CO

\(d_{O_2;CO}=\frac{M_{O_2}}{M_{CO}}=\frac{2\times16}{1\times12+1\times16}=\frac{8}{7}\)

c) không khí

\(d_{O_2;kk}=\frac{M_{O_2}}{M_{kk}}=\frac{2\times16}{29}=\frac{32}{29}\)

1. a) m_Fe2O3 = 0,5.160 = 80 (g)

b) m_CO2 = 0,15.44 = 6,6 (g)

c) n_O2 = 5,6/22,4 = 0,25 (mol) => m_O2 = 0,25.32 = 8 (g)

d) n_H2 = 8,96/22,4 = 0,4 (mol) => m_H2 = 0,4.2 = 0,8 (g)

Bài 1 :

Ta có : \(\left\{{}\begin{matrix}m_{H2SO4}=39,2\\m_{HNO3}=12,6\end{matrix}\right.\) \(\left(g\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{H2SO4}=\dfrac{m}{M}=0,4\\n_{HNO3}=\dfrac{m}{M}=0,2\end{matrix}\right.\) \(\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}\left\{{}\begin{matrix}n_H=2.0,4=0,8\\n_S=0,4.1=0,4\\n_O=4.0,4=1,6\end{matrix}\right.\\\left\{{}\begin{matrix}n_H=0,2.1=0,2\\n_N=0,2.1=0,2\\n_O=0,2.3=0,6\end{matrix}\right.\end{matrix}\right.\) ( mol )

\(\Rightarrow\left\{{}\begin{matrix}n_O=1,6+0,6=2,2\\n_N=0,2\\n_S=0,4\end{matrix}\right.\) ( mol )

Vậy ....

Bài 2 :

\(CH_4+2O_2\rightarrow CO_2+2H_2O\)

\(C_2H_6+\dfrac{7}{2}O_2\rightarrow2CO_2+3H_2O\)

\(TheoPTHH:n_{O2}=2n_{CH4}+\dfrac{7}{2}n_{C2H6}=1,25\left(mol\right)\)

\(\Rightarrow V=n.22,4=28\left(l\right)\)

\(a.2KClO_3-^{t^o}\rightarrow2KCl+3O_2\\ n_{O_2}=\dfrac{3}{2}n_{KClO_3}=0,6\left(mol\right)\\ \Rightarrow V_{O_2}=0,6.22,4=13,44\left(l\right)\\ n_{KCl}=n_{KClO_3}=0,4\left(mol\right)\\ \Rightarrow m_{KCl}=0,4.74,5=29,8\left(g\right)\)

a, PT: \(2KClO_3\xrightarrow[MnO_2]{t^o}2KCl+3O_2\)

Ta có: \(n_{KClO_3}=\dfrac{73,5}{122,5}=0,6\left(mol\right)\)

Theo PT: \(n_{O_2}=\dfrac{3}{2}n_{KClO_3}=0,9\left(mol\right)\)

\(\Rightarrow V_{O_2}=0,9.22,4=20,16\left(l\right)\)

b, PT: \(2Mg+O_2\underrightarrow{t^o}2MgO\)

Ta có: \(n_{Mg}=\dfrac{7,2}{24}=0,3\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,3}{2}< \dfrac{0,9}{1}\), ta được O₂ dư.

Theo PT: \(n_{MgO}=n_{Mg}=0,3\left(mol\right)\)

\(\Rightarrow m_{MgO}=0,3.40=12\left(g\right)\)

Bạn tham khảo nhé!