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a) \(n_{O_2}=\dfrac{11,2.20\%}{22,4}=0,1\left(mol\right)\)
PTHH: 2Mg + O2 --to--> 2MgO
0,2<--0,1--------->0,2
=> mMg = 0,2.24 = 4,8 (g)
b) nMgO = 0,2.40 = 8 (g)
\(n_{C_2H_2}=\dfrac{2,8}{22,4}=0,125\left(mol\right)\\ a,2C_2H_2+5O_2\rightarrow\left(t^o\right)4CO_2+2H_2O\\ b,n_{CO_2}=0,125.2=0,25\left(mol\right)\\ m_{CO_2}=0,25.44=11\left(g\right)\\ c,n_{O_2}=\dfrac{5}{2}.0,125=0,3125\left(mol\right)\\ V_{O_2\left(đktc\right)}=0,3125.22,4=7\left(l\right)\\ \Rightarrow V_{kk\left(đktc\right)}=\dfrac{100}{20}.7=35\left(l\right)\)
\(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\\ a,2Mg+O_2\rightarrow\left(t^o\right)2MgO\\ n_{O_2}=\dfrac{0,1}{2}=0,05\left(mol\right)\\ V_{O_2\left(đktc\right)}=0,05.22,4=1,12\left(l\right)\\ b,2KClO_3\rightarrow\left(t^o\right)2KCl+3O_2\\ n_{KClO_3}=\dfrac{0,05.2}{3}=\dfrac{1}{30}\left(mol\right)\\ \Rightarrow m_{KClO_3}=\dfrac{122,5}{30}=\dfrac{49}{12}\left(g\right)\)
\(n_{O_2}=\dfrac{V}{22,4}=\dfrac{11,2}{22,4}=0,5mol\)
PTHH:
\(2Mg+O_2->2MgO\)
2 : 1 : 2 mol
1 : 0,5 : 1 mol
\(m_{Mg}=n.M=1.24=24g\)
\(m_{MgO}=n.M=1.\left(24+16\right)=40g\)
nO2 = 11,2/22,4 = 0,5 (mol)
PTHH: 2Mg + O2 -> (t°) 2MgO
Mol: 1 <--- 0,5 ---> 1
mMg = 1 . 24 = 24 (g)
mMgO = 1 . 40 = 40 (g)
a)
\(4P + 5O_2 \xrightarrow{t^o} 2P_2O_5\)
Sản phẩm : Điphotpho pentaoxit.
b)
\(n_P = \dfrac{6,2}{31} = 0,2(mol)\\ \Rightarrow n_{P_2O_5} = \dfrac{1}{2}n_P = 0,1(mol)\\ \Rightarrow m_{P_2O_5} = 0,1.142 = 14,2(gam)\)
c)
\(n_{O_2} = \dfrac{5}{4}n_P = 0,125(mol)\\ \Rightarrow V_{O_2} = 0,125.22,4 = 2,8(lít)\)
d)
\(V_{không\ khí} = \dfrac{2,8}{20\%} = 14(lít)\)
a, \(2Zn+O_2\underrightarrow{t^o}2ZnO\)
b, \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{Zn}=0,1\left(mol\right)\Rightarrow V_{O_2}=0,1.22,4=2,24\left(l\right)\)
\(\Rightarrow V_{kk}=5V_{O_2}=11,2\left(l\right)\)
c, \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
Theo PT: \(n_{KMnO_4}=2n_{O_2}=0,2\left(mol\right)\Rightarrow m_{KMnO_4}=0,2.158=31,6\left(g\right)\)
a)\(2Mg + O_2 \xrightarrow{t^o} 2MgO\)
b)
\(n_{Mg} = \dfrac{2,4}{24} = 0,1(mol)\)
Theo PTHH :
\(n_{O_2} = \dfrac{1}{2}n_{Mg} = 0,05(mol)\\ \Rightarrow V_{O_2} = 0,05.22,4 = 1,12(lít)\)
c)
\(n_{MgO} = n_{Mg} = 0,1(mol)\\ \Rightarrow m_{MgO} = 0,1.40 = 4(gam)\)
d)
\(V_{không\ khí} = 5V_{O_2} = 1,12.5 = 5,6(lít)\)
PTHH : S + O2 → SO2
a) Áp dụng định luật bảo toàn khối lượng ta có:
\(m_S+m_{O_2}=m_{SO_2}\)
\(\Rightarrow m_{O_2}=m_{SO_2}-m_S=9,6-4,8=4,8\left(g\right)\)
b) \(n_{O_2}=\frac{m}{M}=\frac{4,8}{32}=0,15\left(mol\right)\)
\(\Rightarrow V_{O_2}=n.22,4=0,15.24=3,6\left(l\right)\)
c) \(V_{O_2}=V_{KK}.\frac{1}{5}\Rightarrow V_{KK}=V_{O_2}.5=3,6.5=18\left(l\right)\)
\(n_{CO_2}=\dfrac{4,48}{22,4}=0,2mol\)
\(C_2H_5OH+3O_2\underrightarrow{t^o}2CO_2+3H_2O\)
0,2 0,6 0,4 0,6
a)\(m_{C_2H_5OH}=0,2\cdot46=9,2g\)
b)\(V_{O_2}=0,6\cdot22,4=13,44l\)
\(\Rightarrow V_{kk}=5V_{O_2}=5\cdot13,44=67,2l\)
nMg = 7,2/24 = 0,3 (mol)
PTHH: 2Mg + O2 -> (t°) 2MgO
Mol: 0,3 ---> 0,15 ---> 0,3
VO2 = 0,15 . 22,4 = 3,36 (l)
Vkk = 3,36 . 5 = 16,8 (l)
mMgO = 0,3 . 40 = 12 (g)
\(a,n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
PTHH: 2Mg + O2 --to--> 2MgO
0,2---<0,1<--------0,2
Mg + 2HCl ---> MgCl2 + H2
0,2--->0,4
=> \(\left\{{}\begin{matrix}b,m_{Mg}=0,2.24=4,8\left(g\right)\\c,V_{kk}=0,1.5.22,4=11,2\left(l\right)\\d,m_{ddHCl}=\dfrac{0,4.36,5}{10\%}=146\left(g\right)\end{matrix}\right.\)