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\(n_{Al}=\dfrac{4,5}{27}=\dfrac{1}{6}mol\)
\(n_{H_2}=\dfrac{3,36}{22,4}=0,15mol\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
0,1 0,05 0,05 0,15 ( mol )
=> Al dư
\(m_{Al\left(dư\right)}=\left(\dfrac{1}{6}-0,1\right).27=1,8g\)
\(m_{Al_2\left(SO_4\right)_3}=0,05.342=17,1g\)
\(m_{H_2SO_4}=0,15.98=14,7g\)
nH2 = 6.72 / 22.4 = 0.3 (mol)
Mg + H2SO4 => MgSO4 + H2
0.3.......0.3.............0.3........0.3
mMg = 0.3 * 24 = 7.2 (g)
mH2SO4 = 0.3 * 98 = 29.4 (g)
mddH2SO4 = 29.4 * 100 / 19.6 = 150 (g)
mMgSO4 = 0.3 * 120 = 36 (g)
\(a) n_{Al} = \dfrac{7,5.36\%}{27} = 0,1(mol)\\ n_{Mg} = \dfrac{7,5-0,1.27}{24} = 0,2(mol)\\ 2Al + 6HCl \to 2AlCl_3 + 3H_2\\ Mg + 2HCl \to MgCl_2 + H_2\\ n_{AlCl_3} = n_{Al}= 0,1(mol) \Rightarrow m_{AlCl_3} = 0,1.133,5 = 13,35(gam)\\ n_{MgCl_2}= n_{Mg} = 0,2(mol) \Rightarrow m_{MgCl_2} = 0,2.95 = 19(gam)\\ b) n_{H_2} = \dfrac{3}{2}n_{Al} + n_{Mg} = 0,35(mol)\\ V_{H_2} = 0,35.22,4 = 7,84(lít)\)
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!
a, \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
\(m_{HCl}=36,5.15\%=5,475\left(g\right)\Rightarrow n_{HCl}=\dfrac{5,475}{36,5}=0,15\left(mol\right)\)
PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,15}{2}\), ta được Mg dư.
Theo PT: \(n_{H_2}=\dfrac{1}{2}n_{HCl}=0,075\left(mol\right)\Rightarrow V_{H_2}=0,075.22,4=1,68\left(l\right)\)
b, \(n_{Mg\left(pư\right)}=\dfrac{1}{2}n_{HCl}=0,075\left(mol\right)\Rightarrow n_{Mg\left(dư\right)}=0,1-0,075=0,025\left(mol\right)\)
\(\Rightarrow m_{Mg\left(dư\right)}=0,025.24=0,6\left(g\right)\)
c, - Cách 1:
\(n_{MgCl_2}=\dfrac{1}{2}n_{HCl}=0,075\left(mol\right)\Rightarrow m_{MgCl_2}=0,075.95=7,125\left(g\right)\)
- Cách 2:
Theo ĐLBT KL, có: mMg (pư) + mHCl = mMgCl2 + mH2
⇒ mMgCl2 = 2,4 - 0,6 + 5,475 - 0,075.2 = 7,125 (g)
\(a,n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\\ PTHH:Mg+H_2SO_4\rightarrow MgSO_4+H_2\uparrow\left(1\right)\\ Theo.pt\left(1\right):n_{H_2}=n_{MgSO_4}=n_{Mg}=0,1\left(mol\right)\\ V_{H_2}=0,1.22,4=2,24\left(l\right)\\ m_{MgSO_4}=0,1.120=12\left(g\right)\\ b,PTHH:CuO+H_2\underrightarrow{t^o}Cu+H_2O\left(2\right)\\ Theo.pt\left(2\right):n_{Cu}=n_{H_2}=0,1\left(mol\right)\\ m_{Cu}=0,1.64=6,4\left(g\right)\)
2Al+3H2SO4->Al2(SO4)3+3H2
0,1----------------------0,075----0,15
n H2=0,15 mol
=>mAl=0,1.27=2,7g
=>m Al2(SO4)3=0,075.342=25,65g
a) PTHH: \(2Al+3H_2SO_2\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
b) \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
\(n_{Al}=\dfrac{2}{3}.0,15=0,1\left(mol\right)\)
\(m_{Al}=0,1.27=2,7\left(g\right)\)
c) \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}.0,1=0,05\left(mol\right)\)
\(m_{Al_2\left(SO_4\right)_3}=0,05.342=17,1\left(g\right)\)
a, PT: \(R+H_2SO_4\rightarrow RSO_4+H_2\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
b, Ta có: \(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
Theo PT: \(n_{H_2SO_4}=n_{H_2}=0,4\left(mol\right)\)
\(\Rightarrow V_{ddH_2SO_4}=\dfrac{0,4}{2}=0,2\left(l\right)\)
Theo ĐLBT KL, có: mKL + mH2SO4 = m muối + mH2
⇒ m muối = 7,8 + 0,4.98 - 0,4.2 = 46,2 (g)
c, Gọi: nR = x (mol) → nAl = 2x (mol)
Theo PT: \(n_{H_2}=n_R+\dfrac{3}{2}n_{Al}=x+\dfrac{3}{2}.2x=0,4\left(mol\right)\Rightarrow x=0,1\left(mol\right)\)
⇒ nR = 0,1 (mol)
nAl = 0,1.2 = 0,2 (mol)
⇒ 0,1.MR + 0,2.27 = 7,8 ⇒ MR = 24 (g/mol)
Vậy: R là Mg.
Bài 1:
Ta có: \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
PTHH: Mg + H2SO4 (loãng) -> MgSO4 + H2
Theo PTHH và đb, ta có:
\(n_{H_2}=n_{H_2SO_4\left(loãng\right)}=n_{MgSO_4}=n_{Mg}=0,1\left(mol\right)\)
a) \(V_{H_2\left(đktc\right)}=0,1.22,4=2,24\left(l\right)\)
b) Số phân tử muối MgSO4:
\(0,1.6.10^{23}=0,6.10^{23}\) (phân tử)
\(m_{MgSO_4}=0,1.120=12\left(g\right)\)
2,Ta co pthh
Al+3H2SO4\(\rightarrow\)Al2(SO4)3+3H2
theo de bai ta co
nAl=\(\dfrac{4,05}{27}=0,15mol\)
nH2=\(\dfrac{3,36}{22,4}=0,15mol\)
theo pthh
nAl=\(\dfrac{0,15}{1}mol>nH2=\dfrac{0,15}{3}mol\)
\(\Rightarrow\)So mol cua Al du ( tinh theo so mol cua H2 )
a, Theo pthh
nAl= \(\dfrac{1}{3}nH2=\dfrac{1}{3}0,15=0,05mol\)
\(\Rightarrow\)Khoi luong Al PU la
mAl= 0,05.27=1,35 g
b, theo pthh
nAl2(SO4)3=\(\dfrac{1}{3}nH2=\dfrac{1}{3}0,15=0,05mol\)
\(\Rightarrow\)mAl2(SO4)3=0,05.342=17,1 g
Khoi luong Al du la
mAl= (0,15-0,05).27=2,7 g
c, theo pthh
nH2SO4=nH2=0,15 mol
khoi luong cua H2SO4 da phan ung la
mH2SO4=0,15.98=14,7 g