\(n_{H_2}=\dfrac{2,479}{24,79}=0,1mol\\ Mg+2HCl\rightarrow MgCl_2+H_2\\ n_{Mg}=n_{H_2}=0,1mol\\ m_{Mg}=0,1.24=2,4g\)

Ta có: \(n_{H_2}=\dfrac{2,479}{24,79}=0,1\left(mol\right)\)

PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)

_____0,1_____0,2______0,1___0,1 (mol)

a, m_Mg = 0,1.24 = 2,4 (g)

b, m_HCl = 0,2.36,5 = 7,3 (g)

c, Cách 1: m_MgCl2 = 0,1.95 = 9,5 (g)

Cách 2: Theo ĐLBT KL, có: m_Mg + m_HCl = m_MgCl2 + m_H2

⇒ m_MgCl2 = 2,4 + 7,3 - 0,1.2 = 9,5 (g)

`#3107.101107`

n của Hydrogen đã tham gia phản ứng là:

\(n_{\text{H}_2}=\dfrac{2,479}{24,79}=0,1\left(mol\right)\)

Theo PTHH: 

1 mol H₂ p.ứ sẽ thu được 1 mol Mg

`=> 0,1` mol H₂ thu được `0,1` mol Mg

m của Mg đã tham gia vào phản ứng là:

\(m_{\text{Mg}}=n_{\text{Mg}}\cdot M_{\text{Mg}}=0,1\cdot24=2,4\left(g\right)\).

Ta có: \(n_{H_2}=\dfrac{7,437}{24,79}=0,3\left(mol\right)\)

PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)

a, \(n_{Mg}=n_{H_2}=0,3\left(mol\right)\Rightarrow m_{Mg}=0,3.24=7,2\left(g\right)\)

b, \(n_{HCl}=2n_{H_2}=0,6\left(mol\right)\Rightarrow m_{HCl}=0,6.36,5=21,9\left(g\right)\)

c, Cách 1: \(n_{MgCl_2}=n_{H_2}=0,3\left(mol\right)\Rightarrow m_{MgCl_2}=0,3.95=28,5\left(g\right)\)

Cách 2: Theo ĐLBT KL, có: m_Mg + m_HCl = m_MgCl2 + m_H

⇒ m_MgCl2 = 7,2 + 21,9 - 0,3.2 = 28,5 (g)

Nếu có thể thì lần sau bạn nên đăng tách từng bài ra nhé!

Bài 1:

PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)

Ta có: \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)

\(n_{HCl}=\dfrac{3,65}{36,5}=0,1\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,1}{2}\) , ta được Mg dư.

Theo PT: \(n_{Mg\left(pư\right)}=n_{MgCl_2}=n_{H_2}=\dfrac{1}{2}n_{HCl}=0,05\left(mol\right)\)

\(\Rightarrow n_{Mg\left(dư\right)}=0,1-0,05=0,05\left(mol\right)\)

\(\Rightarrow m_{Mg\left(dư\right)}=0,05.24=1,2\left(g\right)\)

\(m_{MgCl_2}=0,05.95=4,75\left(g\right)\)

\(V_{H_2}=0,05.22,4=1,12\left(l\right)\)

Bài 2:

PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

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

\(n_{H_2SO_4}=\dfrac{14,7}{98}=0,15\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,2}{2}>\dfrac{0,15}{3}\) , ta được Al dư.

Theo PT: \(\left\{{}\begin{matrix}n_{Al\left(pư\right)}=\dfrac{2}{3}n_{H_2SO_4}=0,1\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_{H_2SO_4}=0,05\left(mol\right)\\n_{H_2}=n_{H_2SO_4}=0,15\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow n_{Al\left(dư\right)}=0,2-0,1=0,1\left(mol\right)\)

\(\Rightarrow m_{Al\left(dư\right)}=0,1.27=2,7\left(g\right)\)

\(m_{Al_2\left(SO_4\right)_3}=0,05.342=17,1\left(g\right)\)

\(V_{H_2}=0,15.22,4=3,36\left(l\right)\)

Bài 3:

PT: \(2M+6HCl\rightarrow2MCl_3+3H_2\)

Ta có: \(n_{H_2}=\dfrac{4,704}{22,4}=0,21\left(mol\right)\)

Theo PT: \(n_M=\dfrac{2}{3}n_{H_2}=0,14\left(mol\right)\)

\(\Rightarrow M_M=\dfrac{3,78}{0,14}=27\left(g/mol\right)\)

Vậy: M là nhôm (Al).

Bài 4:

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

Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{KMnO_4}=0,2\left(mol\right)\)

PT: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

Ta có: \(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,2}{4}>\dfrac{0,2}{5}\) , ta được P dư.

Theo PT: \(n_{P_2O_5}=\dfrac{2}{5}n_{O_2}=0,08\left(mol\right)\)

\(\Rightarrow m_{P_2O_5}=0,08.142=11,36\left(g\right)\)

Bạn tham khảo nhé!

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

PTHH: Mg + 2HCl --> MgCl₂ + H₂

_____0,2------------------------>0,2

=> V_H2 = 0,2.24,79 = 4,958 (l)

\(n_{Mg}=\dfrac{3,12}{24}=0,13\left(mol\right)\)

\(n_{H_2}=\dfrac{2,2311}{25,79}=0,09\left(mol\right)\)

PTHH :

\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)

0,09     0,18         0,09     0,09

\(\dfrac{0,13}{1}>\dfrac{0,09}{1}\) --> Mg dư

\(m_{MgCl_2}=0,09.95=8,55\left(g\right)\)

PTHH :

\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)

0,13   0,26         0,13         0,13

\(V_{H_2\left(lt\right)}=0,13.24,79=3,2227\left(l\right)\)

\(H=\dfrac{2,2311}{3,2227}.100\%\approx69,23\%\)

PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)

Ta có: \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{Mg}=n_{H_2}=n_{MgCl_2}=0,2mol\\n_{HCl}=0,4mol\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{HCl}=0,4\cdot36,5=14,6\left(g\right)\\m_{Mg}=0,2\cdot24=4,8\left(g\right)\\m_{MgCl_2}=0,2\cdot95=19\left(g\right)\end{matrix}\right.\)

Ta có PTHH: Mg + 2HCl -----> MgCl₂ + H₂.

n_H2=4,48/22,4=0,2(mol)

Theo PT, ta có: n_Mg= n_H2 = 0,2(mol)

=> m_Mg=0,2.24=4,8(g)

Ta có: n_HCl=2 . 0,2=0,4(mol)

=> m_HCl=0,4.37,5=15(g)

Ta có: n_MgCl2=n_H2=0,2(mol)

=> m_MgCl2=0,2 . 95=19(g)