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a. Công thức về khối lượng:
\(m_{Fe_2O_3}+m_{H_2}=m_{Fe}+m_{H_2O}\)
b. Áp dụng câu a, ta có:
\(m_{Fe_2O_3}+2=56+18\)
\(\Leftrightarrow m_{Fe_2O_3}=56+18-2\)
\(\Leftrightarrow m_{Fe_2O_3}=72\left(g\right)\)
\(a)3H_2+Fe_2O_3-^{t^o}\rightarrow2Fe+3H_2O\\b)BTKL:m_{H_2}+m_{Fe_2O_3}=m_{Fe}+m_{H_2O}\\ \Leftrightarrow2+m_{Fe_2O_3}=56+18 \\ \Rightarrow m_{Fe_2O_3}=72\left(g\right)\)
\(a,Fe_2O_3+3H_2\to2Fe+3H_2O\\ b,n_{Fe}=\dfrac{21}{56}=0,375(mol)\\ \Rightarrow n_{Fe_2O_3}=0,1875(mol)\\ \Rightarrow m_{Fe_2O_3}=0,1875.160=30(g)\)
PTHH: \(Fe_2O_3+3H_2\xrightarrow[]{t^o}2Fe+3H_2O\)
Ta có: \(n_{Fe}=\dfrac{21}{56}=0,375\left(mol\right)\)
\(\Rightarrow n_{Fe_2O_3}=0,1875\left(mol\right)\) \(\Rightarrow m_{Fe_2O_3}=0,1875\cdot160=30\left(g\right)\)
$a)n_{Fe}=\dfrac{42}{56}=0,75(mol)$
$Fe_2O_3+3H_2\xrightarrow{t^o}2Fe+3H_2O$
$\Rightarrow n_{Fe_2O_3}=0,5n_{Fe}=0,375(mol)$
$\Rightarrow m_{Fe_2O_3}=0,375.160=60(g)$
$b)n_{H_2O}=1,5n_{Fe}=1,125(mol)$
$\Rightarrow m_{H_2O}=1,125.18=20,25(g)$
\(n_{Fe_2O_3}=\dfrac{32}{160}=0,2\left(mol\right)\\ PTHH:Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\\ Mol:0,2\rightarrow0,6\rightarrow0,4\\ \rightarrow\left\{{}\begin{matrix}m_{Fe}=0,4.56=22,4\left(g\right)\\V_{H_2}=0,6.22,4=13,44\left(l\right)\end{matrix}\right.\)
\(n_{O_2}=\dfrac{6,4}{32}=0,2\left(mol\right)\\ PTHH:2H_2+O_2\underrightarrow{t^o}2H_2O\\ LTL:\dfrac{0,6}{2}>0,2\rightarrow O_2.dư\\ n_{H_2\left(Pư\right)}=0,2.2=0,4\left(mol\right)\\ \rightarrow m_{H_2\left(dư\right)}=\left(0,6-0,4\right).2=0,4\left(g\right)\)
\(a,2Fe(OH)_3\xrightarrow{t^o}Fe_2O_3+3H_2O\\ b,m_{Fe(OH)_3}=m_{Fe_2O_3}+m_{H_2O}\\ c,m_{Fe(OH)_3(p/ứ)}=160+54=214(g)\\ \Rightarrow \%_{Fe(OH)_3(phân hủy)}=\dfrac{214}{400}.100\%=53,5\%\)
\(n_{Fe_2O_3}=\dfrac{32}{160}=0.2\left(mol\right)\)
\(Fe_2O_3+3H_2\underrightarrow{^{^{t^o}}}2Fe+3H_2O\)
\(0.2........0.6........0.4........0.6\)
\(V_{H_2}=0.6\cdot22.4=13.44\left(l\right)\)
\(m_{Fe}=0.4\cdot56=22.4\left(g\right)\)
Số phân tử H2O là : \(0.6\cdot6\cdot10^{23}=3.6\cdot10^{23}\left(pt\right)\)
PTHH: \(Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)
a+b) \(n_{Fe}=\dfrac{22,4}{56}=0,4\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{Fe_2O_3}=0,2\left(mol\right)\\n_{H_2}=0,6\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Fe_2O_3}=0,2\cdot160=32\left(g\right)\\V_{H_2}=0,6\cdot22,4=13,44\left(l\right)\end{matrix}\right.\)
c) PTHH: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\uparrow\)
Theo PTHH: \(n_{Zn}=n_{H_2}=0,6\left(mol\right)\)
\(\Rightarrow m_{Zn}=0,6\cdot65=39\left(g\right)\)
a,
nFe = 22,4/56 = 0,4 (mol)
PTHH
Fe2O3 + 3H2 ---to----) 2Fe + 3H2O (1)
theo phương trình (1) ,ta có:
nFe2O3 = 0,4 x 2 / 1 = 0,8 (mol)
mFe2O3 = 160 x 0,8 = 128 (g)
b,
theo pt (1)
nH2 = (0,4 x 3)/2 = 0,6 (mol)
=) VH2 = 0,6 x 22,4 = 13,44 (L)
c,
PTHH
Zn + H2SO4 -------------) ZnSO4 + H2 (2)
Số mol H2 cần dùng là 0,6 (mol)
Theo PT (2) :
nZn = nH2 ==) nZn = 0,6 x 65 = 39 (g)
Câu 1:
2Mg + O2\(\rightarrow\) 2MgO
Ta có: nMg=\(\frac{4,8}{24}\)=0,2 mol;
nMgO=\(\frac{8}{40}\)=0,2 mol
\(\rightarrow\) nMg=nMgO nên phản ứng hoàn toàn
BTKL: mMg + mO2=mMgO
\(\rightarrow\)mO2=mMgO-mMg=\(\text{8-4,8=3,2 gam}\)
Câu2
3H2 + Fe2O3\(\rightarrow\) 2Fe + 3H2O
Bảo toàn khối lượng:
∑mH2 + mFe2O3 = ∑mFe + mH2O
\(\rightarrow\) mFe2O3 = ∑mFe + mH2O - mH2
=\(\text{11,2 + 5, 4 - 0,6 =16(g)}\)
câu 1
a) theo ĐLBTKL ta có:
mMg + mO2 = mMgO
b) mO2 = mMgO - mMg
mO2 = 8 - 4,8 = 3,2 (g)
$a.PTHH :$
$2Fe(OH)_3\overset{t^O}\to Fe_2O_3+3H_2O$
$b.n_{Fe(OH)_3}=\dfrac{32,1}{107}=0,3mol$
$Theo$ $pt :$
$n_{Fe_2O_3}=\dfrac{1}{2}.n_{Fe_2O_3}=\dfrac{1}{2}.0,3=0,15mol$
\(\Rightarrow\)$m_{Fe_2O_3}=0,15.160=24g$