Tính khối lượng của Cu(OH)2 để có số phân tử gấp 1,5 lần số phân tử có trong 1,56g Al(OH)3
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`@` `\text {dnammv}`
\(\text{Al}_2\text{O}_3:\)
`- \text {NTK:}`
\(+\text{Al: 27 amu}\)
\(+\text{O: 16 amu}\)
`->`\(\text{PTK}_{\text{Al}_2\text{O}_3}=27\cdot2+16\cdot3=102\text{ }< \text{amu}>\)
\(\text{Cu(OH)}_2:\)
`- \text {NTK:}`
\(+\text{Cu: 64 amu}\)
\(+\text{H: 1 amu}\)
\(+\text{O: 16 amu}\)
`->`\(\text{PTK}_{\text{Cu}\left(\text{OH}\right)_2}=64+\left(16+1\right)\cdot2=98\text{ }< \text{amu}>.\)
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\(a,m_{CaSO_4}=136.0,25=34\left(g\right)\\ b,n_{Cu_2O}=\dfrac{3.10^{23}}{6.10^{23}}=0,5\left(mol\right)\\ m_{Cu_2O}=0,5.144=72\left(g\right)\\ c,n_{NH_3}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\\ m_{NH_3}=17.0,3=5,1\left(g\right)\\ d,m_{C_4H_{10}}=0,17.58=9,86\left(g\right)\\ e,n_{Cu\left(OH\right)_2}=\dfrac{4,5.10^{25}}{6.10^{23}}=75\left(mol\right)\\ m_{Cu\left(OH\right)_2}=98.75=7350\left(g\right)\\ g,m_{MgO}=0,48.40=19,2\left(g\right)\\ h,n_{CO_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\ m_{CO_2}=44.0,15=6,6\left(g\right)\\ i,m_{Al\left(OH\right)_3}=78.0,25=19,5\left(g\right)\\\)
Các câu còn lại em làm tương tự nha!
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a, \(n_{Al_2\left(SO_4\right)_3}=\dfrac{42,75}{342}=0,125\left(mol\right)\)
\(n_O=12n_{Al_2\left(SO_4\right)_3}=1,5\left(mol\right)\)
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M(OH)2 + H2SO4-----> MSO4 + 2H2O
d= MSO4/M(OH)2=\(\frac{M+96}{M+34}=2,069\)
1,069M=96-34.2,069
M=24=Mg
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a)
$x = 2 ; y = 3$
PTHH : $2Al(OH)_3 + 3H_2SO_4 \to Al_2(SO_4)_3 + 6H_2O$
b)
Tỉ lệ số phân tử $Al(OH)_3$ : số phân tử $H_2SO_4$ là 2 : 3
c)
$\%Al = \dfrac{27}{78}.100\% =34,6\%$
d)
$n_{Al(OH)_3} = \dfrac{7,8}{78} = 0,1(mol)$
Theo PTHH : $n_{Al_2(SO_4)_3} = \dfrac{1}{2}n_{Al(OH)_3} = 0,05(mol)$
$m_{Al_2(SO_4)_3} = 0,05.342 = 17,1(gam)$
\(M_{Al\left(OH\right)_3}=1\times27+3\times16+3\times1=78\) (g/mol)
\(n_{Al\left(OH\right)_3}=\frac{m_{Al\left(OH\right)_3}}{M_{Al\left(OH\right)_3}}=\frac{1,56}{78}=0,02\left(mol\right)\)
Số phân tử Al(OH)3\(=n_{Al\left(OH\right)_3}\times N=0,02\times6\times10^{23}=0,12\times10^{23}\) (phân tử)
Số phân tử Cu(OH)2 \(=1,5\times s\text{ố}ph\text{â}n\text{tử}Al\left(OH\right)_3=1,5\times0,12\times10^{23}=0,18\times10^{23}\) (phân tử)
\(n_{Cu\left(OH\right)_2}=\frac{\text{số phân tử}Cu\left(OH\right)_2}{N}=\frac{0,18\times10^{23}}{6\times10^{23}}=0,03\left(mol\right)\)
\(M_{Cu\left(OH\right)_2}=1\times64+2\times16+2\times1=98\) (g/mol)
\(m_{Cu\left(OH\right)_2}=n_{Cu\left(OH\right)_2}\times M_{Cu\left(OH\right)_2}=0,03\times98=2,94\left(g\right)\)