Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a. Ag không phản ứng nên ta có PTHH: \(2Mg+O_2\rightarrow^{t^o}2MgO\)
\(\rightarrow m_{O_2}=m_{hh}-m_{\mu\text{ối}}=18,8-15,6=3,2g\)
\(\rightarrow n_{O_2}=\frac{3,2}{32}=0,1mol\)
b. \(\rightarrow V_{O_2}=n.22,4=22,4.0,1=2,24l\)
\(\rightarrow V_{kk}=4,48.5=11,2l\)
c. Có \(n_{Mg}=2n_{O_2}=0,2l\)
\(\rightarrow m_{Mg}=0,2.24=4,8g\)
\(\rightarrow\%m_{Mg}=\frac{4,8.100}{15,6}\approx30,77\%\)
\(\rightarrow\%m_{Ag}=100\%-30,77\%=69,23\%\)
Gọi \(\left\{{}\begin{matrix}n_{Mg}=x\left(mol\right)\\x_{Ca}=y\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}24x+40y=17,6\\x=2y\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,4\\y=0,2\end{matrix}\right.\)
a)\(m_{Mg}=0,4\cdot24=9,6g\)
\(m_{Ca}=0,2\cdot40=8g\)
b)\(2Mg+O_2\underrightarrow{t^o}2MgO\)
\(2Ca+O_2\underrightarrow{t^o}2CaO\)
Từ hai pt: \(\Rightarrow\Sigma n_{O_2}=\dfrac{1}{2}n_{Mg}+\dfrac{1}{2}n_{Ca}=\dfrac{1}{2}\cdot0,4+\dfrac{1}{2}\cdot0,2=0,3mol\)
\(\Rightarrow m_{O_2}=0,3\cdot32=9,6g\)
\(V_{O_2}=0,3\cdot22,4=6,72l\)
\(\Rightarrow V_{kk}=5V_{O_2}=5\cdot6,72=33,6l\)
a)
Có \(\left\{{}\begin{matrix}24.n_{Mg}+40.n_{Ca}=17,6\\n_{Mg}=2.n_{Ca}\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}n_{Ca}=0,2\left(mol\right)\\n_{Mg}=0,4\left(mol\right)\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}m_{Ca}=0,2.40=8\left(g\right)\\m_{Mg}=0,4.24=9,6\left(g\right)\end{matrix}\right.\)
b)
PTHH: 2Ca + O2 --to--> 2CaO
0,2-->0,1
2Mg + O2 --to--> 2MgO
0,4--->0,2
=> \(V_{O_2}=\left(0,1+0,2\right).22,4=6,72\left(l\right)\)
\(V_{kk}=6,72.5=33,6\left(l\right)\)
PTHH: 2CO+O2to→2CO2 (1)
4H2+O2to→2H2O (2)
b) Ta có:
ΣnO2=\(\dfrac{9,6}{32}\)=0,3(mol)
nCO2=\(\dfrac{8,8}{44}\)=0,2(mol)
⇒{nO2(1)=0,1mol
nO2(2)=0,2mol
⇒{mCO=0,1⋅28=2,8(g)
mH2=0,2⋅2=0,4(g)
⇒%mCO=\(\dfrac{2,8}{2,8+0,4}\)⋅100%=87,5%
%mH2=12,5%
\(nO_2=\dfrac{9,6}{32}=0,3\left(mol\right)\)
\(nCO_2=\dfrac{8,8}{44}=0,2\left(mol\right)\)
\(2CO+O_2\underrightarrow{t^o}2CO_2\)
2 1 2 (mol)
0,2 0,1 0,2 (mol)
\(4H_2+O_2\underrightarrow{t^o}2H_2O\)
4 1 2 (mol)
0,8 0,2 0,4 (mol)
\(mCO=0,2.28=5,6\left(g\right)\)
\(mH_2=0,8.2=0,16\left(g\right)\)
\(\%mCO=\dfrac{5,6.100}{5,6+0,16}=97,22\%\)
\(\%mH_2=100-97,22=2,78\%\)
a) PTHH: \(2CO+O_2\underrightarrow{t^o}2CO_2\) (1)
\(4H_2+O_2\underrightarrow{t^o}2H_2O\) (2)
b) Ta có: \(\left\{{}\begin{matrix}\Sigma n_{O_2}=\dfrac{9,6}{32}=0,3\left(mol\right)\\n_{CO_2}=\dfrac{8,8}{44}=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}n_{O_2\left(1\right)}=0,1mol\\n_{O_2\left(2\right)}=0,2mol\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{CO}=0,1\cdot28=2,8\left(g\right)\\m_{H_2}=0,2\cdot2=0,4\left(g\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\%m_{CO}=\dfrac{2,8}{2,8+0,4}\cdot100\%=87,5\%\\\%m_{H_2}=12,5\%\end{matrix}\right.\)
c) PTHH: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\uparrow\)
Theo PTHH: \(n_{KMnO_4}=2n_{O_2}=0,6mol\)
\(\Rightarrow m_{KMnO_4}=0,6\cdot158=94,8\left(g\right)\)
a, PT: \(2Cu+O_2\underrightarrow{t^o}2CuO\)
\(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
\(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
\(Fe_3O_4+4H_2\underrightarrow{t^o}3Fe+4H_2O\)
Gọi: \(\left\{{}\begin{matrix}n_{Cu}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\\n_{Al}=z\left(mol\right)\end{matrix}\right.\) ⇒ 64x + 56y + 27z = 40,4 (1)
Theo PT: \(\left\{{}\begin{matrix}n_{CuO}=n_{Cu}=x\left(mol\right)\\n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=\dfrac{1}{3}y\left(mol\right)\\n_{Al_2O_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}z\left(mol\right)\end{matrix}\right.\)
⇒ 80x + 232.1/3x + 102.1/2z = 59,6 (2)
- Chất rắn A gồm: Cu, Fe và Al3O3.
⇒ 64x + 56y + 102.1/2z = 50 (3)
Từ (1), (2) và (3) \(\Rightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,3\left(mol\right)\\z=0,4\left(mol\right)\end{matrix}\right.\)
⇒ mCu = 0,2.64 = 12,8 (g)
mFe = 0,3.56 = 16,8 (g)
mAl = 0,4.27 = 10,8 (g)
b, Theo PT: \(n_{H_2}=n_{Cu}+\dfrac{4}{3}n_{Fe}=0,6\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,6.22,4=13,44\left(l\right)\)
\(n_{H_2}=\dfrac{0,953m}{22,4}=0,042545m\left(mol\right)\\ Đặt:n_{Mg}=x\left(mol\right);n_{Al}=y\left(mol\right);n_{Cu}=z\left(mol\right)\left(x,y,z>0\right)\\\Rightarrow \left\{{}\begin{matrix}24x+27y+64z=m\\40x+51y+80z=1,72m\\x+1,5y=0,042545m\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x\approx0,012845m\\y\approx0,0198m\\z\approx0,002455m\end{matrix}\right.\\ \Rightarrow\%m_{Cu}\approx\dfrac{0,002455.64m}{m}.100\%\approx15,712\%\\ \%m_{Al}\approx\dfrac{27.0,0198m}{m}.100\%\approx53,46\%\\ \%m_{Mg}\approx\dfrac{0,012845.24m}{m}.100\%\approx30,828\%\)
2Cu+O2-->2CuO
Vì Ag ko cháy thì hỗn hợp chất rắn sau khi đốt là CuO và Ag
gọi x và y lần lượt là số mol của Cu và Ag
=>tacó hệ pt :
64x+108y=10
8ỹ+108y=11,6
==>x=0,1 mol ;y=0,3 mol
=>%mCu =\(\frac{64.0,1}{10}.100\%\)=64%
=)%mAg=100-64=36%