Tuổi bố nhiều hơn 1/4 tuổi con là 2 tuổi . Biết bố hơn con 40 tuổi .Tính tuổi của mỗi người

Nhầm! 

   \(n_{O_2}=\frac{1.68}{22.4}=0.075\left(mol\right)\)

 \(4Na+O_2\rightarrow2Na_2O\)

      x         \(\frac{1}{4}x\)          \(\frac{1}{2}x\)

  \(4K+O_2\rightarrow2K_2O\)

  x         \(\frac{1}{4}x\)          \(\frac{1}{2}x\)

Theo bài ra ta có \(\begin{cases}23x+39y=10.1\\\frac{1}{4}x+\frac{1}{4}y=0.075\end{cases}\)     \(\begin{cases}0.1\\0.2\end{cases}\)

\(m_{Na}=0.1\times23=2.3\left(g\right)\)     

\(m_K=0.2\times39=7.8\left(g\right)\)

Nam: (1) What are you doing , Tuan?

Tuan: I am learning English.

Nam: You work too much. You(2) should relax.

Tuan: OK. (3) I  go swimming

Nam: Great idea! (4) Do you often go swimming?

Tuan: Yes. I usually (5) go swimming after school.

           (6) What do you usually do after school, Nam?

Nam: I often play video games.

Tuan: Do you(7) play sports?

Nam: Yes. I sometimes play badminton.

a, \(n_{Fe}=\frac{0.56}{56}=0.01\left(mol\right)\)

 \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

  0.01      0.01       0.01       0.01

\(V_{H_2}=0.01\times22.4=0.224\left(l\right)\)

b, \(m_{H_2SO_4}=0.01\times98=0.98\left(g\right)\)

   \(m_{ddH_2SO_4}=\frac{100\times0.98}{19.6}=5\left(g\right)\)

\(m_{FeSO_4}=0.01\times152=1.52\left(g\right)\)

\(C\%_{FeSO_4}=\frac{1.52\times100}{5}=30.4\%\)

1. A. dishes          B. watches   C. Boxes     D. potatoes            

2.  A. lovely     B. novel             C. cover              D.money     

3. A. father          B. mother         C. growth        D. brother   

4. A. summer        B. student        C. uncle      D. bus 

5. A. during             B. public           C. summer       D. buffalo

6. A. volunteer           B. meet      C. street       D. free     

7. A. idea          B. stripe           C. tidy             D. circus       

8. A. late          B. information     C.start        D. invitation 

9. A. typical        B. lazy     C. Biology     D. dryer      

10. A. great          B. rehearse        C. teacher         D. means   

\(A,\)  Tên khí A là SO₂

\(B,\)  \(n_{SO_2}=\frac{1.12}{22.4}=0.05\left(mol\right)\)

     \(K_2SO_3+H_2SO_4\rightarrow K_2SO_4+SO_2+H_2O\)

        0.05          0.05                         0.05

\(m_{H_2SO_4}=0.05\times98=4.9\left(g\right)\)

\(C\%_{H_2SO_4}=\frac{4.9}{24.5}\times100=20\%\)

\(C,\)

   \(m_{K_2SO_3}=0.05\times158=7.9\left(g\right)\)

\(\%m_{K_2SO_3}=\frac{7.9}{21}\times100=37.6\%\)

\(\%m_{K_2SO_4}=100\%-37.6\%=62.4\%\)