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Ta có : \(M_{kk}=\dfrac{20.32+80.28}{20+80}=28,8\) ( đvc )
\(\Rightarrow d_{\dfrac{KK}{H2}}=\dfrac{M_{kk}}{M_{h2}}=\dfrac{28,8}{2}=14,4\)
Vậy ...
a) Ta có: \(M_{XCO_3}=4\cdot25=100\) \(\Rightarrow M_X=100-12-16\cdot3=40\left(đvC\right)\)
\(\Rightarrow\) X là Canxi (Ca)
b) \(\%O=\dfrac{16\cdot3}{100}\cdot100\%=48\%\)
Bài 3:
a) M(XCO3)=25. M(He)= 25.4=100(đ.v.C)
Mặt khác: M(XCO3)=M(X)+ 60
=> M(X)+60=100
<=>M(X)=40(đ.v.C)
=> X là Canxi (Ca=40)
b) %mO=[(3.16)/100].100=48%
PTK(hợp chất)= 3:17,647%= 17(đ.v.C)
Mặt khác: PTK(hc)=NTK(X)+3
<=>17=NTK(X)+3
<=>NTK(X)=14(đ.v.C)
Vậy X là nito (N)
b) PTK(hc)=17(đ.v.C)
Anh Đạt đẹp trai chúc em học tốt!
a)
$n_{Nito} = \dfrac{6,02.10^{23}}{6,02.10^{23}} = 1(mol)$
$m_{Nito} = 1.14 = 14(gam)$
b)
$n_{Cl} = \dfrac{6,02.10^{23}}{6,02.10^{23}} = 1(mol)$
$m_{Cl} = 1.35,5 = 35,5(gam)$
c)
$n_{H_2O} = \dfrac{6,02.10^{23}}{6,02.10^{23}} = 1(mol)$
$m_{H_2O} = 1.18 = 18(gam)$
a) \(n_{N_2}=\dfrac{6,02.10^{23}}{6,02.10^{23}}=1\left(mol\right)\)
=> \(m_{N_2}=1.28=28\left(g\right)\)
b) \(n_{Cl_2}=\dfrac{6,02.10^{23}}{6,02.10^{23}}=1\left(mol\right)\)
=> \(m_{Cl_2}=1.35,5.2=71\left(g\right)\)
c) \(n_{H_2O}=\dfrac{6,02.10^{23}}{6,02.10^{23}}=1\left(mol\right)\)
=> \(m_{H_2O}=1.18=18\left(g\right)\)
d) \(n_{CaCO_3}=\dfrac{6,02.10^{23}}{6,02.10^{23}}=1\left(mol\right)\)
=> \(m_{CaCO_3}=1.100=100\left(g\right)\)
10
\(n_{Zn}=\dfrac{3,25}{65}=0,05\left(mol\right)\)
\(n_{CuO}=\dfrac{6}{80}=0,075\left(mol\right)\)
\(pthh:Zn+HCl->ZnCl_2+H_2\)
0,05 0,05
\(pthh:CuO+H_2\underrightarrow{t^o}H_2O+Cu\)
LTL : \(\dfrac{0,075}{1}>\dfrac{0,05}{1}\)
=>> CuO dư
theo pthh : \(n_{Cu}=n_{H_2}=0,05\)(mol)
=> \(m_{Cu}=0,05.64=3,2\left(g\right)\)
=> \(m_{CuO\left(d\right)}=\left(0,075-0,05\right).80=2\left(g\right)\)
Câu 10:
\(a) n_{Zn} = \dfrac{3,25}{65} = 0,05 (mol)\\n_{CuO} = \dfrac{6}{80} = 0,075 (mol)\)
PTHH:
Zn + 2HCl ---> ZnCl2 + H2
0,05------------------------->0,05
CuO + H2 --to--> Cu + H2O
LTL: \(0,075>0,05\rightarrow\) CuO dư
b, Theo pthh: \(n_{CuO\left(pư\right)}=n_{Cu}=n_{H_2}=0,05\left(mol\right)\)
\(\rightarrow m_{Cu}=0,05.64=3,2\left(g\right)\)
\(c) \text{chất dư là CuO}\\ \rightarrow m_{CuO (dư)} = (0,075 - 0,05) . 80 = 2 (g)\)
Đặt \(n_{Al}=x\left(mol\right);n_{Mg}=y\left(mol\right)\)
\(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
\(PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\\ Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
Theo đề ta có: \(\left\{{}\begin{matrix}27x+24y=7,8\\\dfrac{3}{2}x+y=0,4\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%_{Al}=\dfrac{0,2\cdot27}{7,8}\cdot100\%\approx69,23\%\\\%_{Mg}=\dfrac{0,1\cdot24}{7,8}\cdot100\%\approx30,77\%\end{matrix}\right.\)
\(n_{KClO_3}=\dfrac{5,5125}{122,5}=0,045\left(mol\right)\\ 2KClO_3\rightarrow\left(t^o\right)2KCl+3O_2\uparrow\\ n_{O_2}=\dfrac{3}{2}.0,045=0,0675\left(mol\right)\\ 2Cu+O_2\rightarrow\left(t^o\right)2CuO\\ n_{CuO}=2.0,0675=0,135\left(mol\right)\\ m_{r\text{ắn}}=m_{CuO}=0,135.80=10,8\left(g\right)\)