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\(n_{Zn}=0,2mol\\ a.2Zn+O_2-^{^{ }t^{^0}}->2ZnO\\ b.m_{ZnO}=0,2.71=14,2g\\ n_{O_2}=0,2:2=0,1mol\\ V_{O_2}=0,1.22,4=2,24L\\ c.2KClO_3-^{^{ }t^{^{ }0}}->2KCl+3O_2\\ n_{KClO_3}=\dfrac{2}{3}.0,1=\dfrac{0,2}{3}mol\\ m_{KClO_3}=122,5\cdot\dfrac{0,2}{3}=8,166g\)
a) 4Al + 3O2 --to--> 2Al2O3
b) \(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\)
PTHH: 4Al + 3O2 --to--> 2Al2O3
0,4-->0,3-------->0,2
VO2(đkc) = 0,3.24,79 = 7,437 (l)
c) mAl2O3 = 0,2.102 = 20,4 (g)
a)\(PTHH:2Na+2H_2O\xrightarrow[]{}2NaOH+H_2\)
b)\(n_{Na}=\dfrac{4,6}{23}=0,2\left(m\right)\)
\(PTHH:2Na+2H_2O\xrightarrow[]{}2NaOH+H_2\)
tỉ lệ :2 2 2 1(mol)
số mol :0,2 0,2 0,2 0,1
\(V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c)\(m_{NaOH}=0,2.40=8\left(g\right)\)
Câu 2:
PTHH: 4P+ 5O2 -to-> 2P2O5
Ta có:
\(n_P=\frac{3,1}{31}=0,1\left(mol\right);\\ n_{O_2}=\frac{2,24}{22,4}=0,1\left(mol\right)\)
Theo PTHH và đề bài, ta có:
\(\frac{0,1}{4}>\frac{0,1}{5}\)
b) => P dư, O2 hết nên tính theo \(n_{O_2}\)
=> \(n_{P\left(phảnứng\right)}=\frac{4.0,1}{5}=0,08\left(mol\right)\\ =>n_{P\left(dư\right)}=0,1-0,08=0,02\left(mol\right)\)
Khối lượng P dư:
\(m_{P\left(dư\right)}=0,02.31=0,62\left(g\right)\)
c) Theo PTHH và đề bài, ta có:
\(n_{P_2O_5}=\frac{2.0,1}{5}=0,04\left(mol\right)\)
Khối lượng P2O5:
\(m_{P_2O_5}=0,04.142=5,68\left(g\right)\)
1) PTHH: Zn+2HCl->ZnCl2+H2
b) \(n_{Zn}=\frac{13}{65}=0,2mol\)
\(n_{H_2}=n_{Zn}=0,2mol\Rightarrow V_{H_2}=0,2.22,4=4,48l\)c) 2H2+O2=>2H2O
\(n_{O_2}=\frac{1}{2}.n_{H_2}=\frac{1}{2}.0,2=0,1mol\Rightarrow V_{O_2}=0,1.22,4=2,24l\Rightarrow V_{kk}=5.V_{O_2}=5.2,24=11,2l\)d) H2+CuO=>Cu+H2O
\(n_{CuO}=\frac{24}{80}=0,3mol\)
Vì: 0,3>0,2=> CuO dư
\(n_{Cu}=n_{H_2}=0,2mol\Rightarrow m_{Cu}=0,2.64=12,8g\)\(n_{CuO\left(dư\right)}=0,3-\left(0,2.1\right)=0,1mol\Rightarrow m_{CuO}=0,1.64=6,4g\Rightarrow m_{rắn}=12,8+6,4=19,2g\)
a/ PTHH:2Al + 6HCl ===> 2AlCl3 + 3H2
nAl = 5,4 / 27 = 0,2 mol
=> nH2 = 0,3 mol
=> mH2 = 0,3 x 2 = 0,6 gam
=> VH2(đktc) = 0,3 x 22,4 = 6,72 lít
b/ => nAlCl3 = 0,3 mol
=> mAlCl3 = 0,2 x 133,5 = 26,7 gam
\(PTHH:4Al+3O_2->2Al_2O_3\)
BĐ 0,4 0,27 (mol)
PU 0,36---->0,27---->0,18 (mol)
CL 0,04---->0------>0,18 (mol)
b)
\(n_{Al}=\dfrac{m}{M}=\dfrac{10,8}{27}=0,4\left(mol\right)\)
\(n_{O_2}=\dfrac{V}{22,4}=\dfrac{6,048}{22,4}=0,27\left(mol\right)\)
\(\dfrac{n_{Al}}{4}>\dfrac{n_{O_2}}{3}\left(\dfrac{0,4}{4}>\dfrac{0,27}{3}\right)\)
=> Al dư, O2 hết (tính theo O2)
\(m_{Al}=n\cdot M=0,04\cdot27=1,08\left(g\right)\)
c)
\(m_{Al_2O_3}=n\cdot M=0,18\cdot\left(27\cdot2+16\cdot3\right)=18,36\left(g\right)\)
a, PT: \(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
b, Ta có: \(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\)
\(n_{O_2}=\dfrac{6,048}{22,4}=0,27\left(mol\right)\)
Xét tỉ lệ: \(\dfrac{0,4}{4}>\dfrac{0,27}{3}\), ta được Al dư.
Theo PT: \(n_{Al\left(pư\right)}=\dfrac{4}{3}n_{O_2}=0,36\left(mol\right)\)
\(\Rightarrow n_{Al\left(dư\right)}=0,4-0,36=0,04\left(mol\right)\)
\(\Rightarrow m_{Al\left(dư\right)}=0,04.27=1,08\left(g\right)\)
c, Theo PT: \(n_{Al_2O_3}=\dfrac{2}{3}n_{Al}=0,18\left(mol\right)\)
\(\Rightarrow m_{Al_2O_3}=0,18.102=18,36\left(g\right)\)
\(n_{Al}=\dfrac{5,4}{27}=0,2mol\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
0,2 0,1 0,3 ( mol )
\(m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2g\)
\(V_{H_2}=0,3.22,4=6,72l\)
\(n_{Al}=\dfrac{m}{M}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
\(a)PTHH:4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
4 3 2
0,2 0,15 0,1 (mol)
\(b)m_{Al_2O_3}=n\cdot M=0,1\cdot\left(27\cdot2+16\cdot3\right)=10,2\left(g\right)\\ c)V_{O_2}=n\cdot24,79=0,15\cdot24,79=3,7185\left(l\right).\)