Đốt cháy hoàn toàn 3,1 g Photpho trong bình chứa khí O2 . Cho nc vào bình để hoà tan hết lượng khí sinh ra thì thu đc 100ml dung dịch axit. Xác định nồng độ mol của dung dịch axit tạo thành.
Help meeeee !!!! Cảm ơn m.n trc ạ
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a) \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b) \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
PTHH: Zn + 2HCl --> ZnCl2 + H2
0,1-->0,2------------->0,1
=> \(C_{M\left(HCl\right)}=\dfrac{0,2}{0,2}=1M\)
c)
PTHH: 2H2 + O2 --to--> 2H2O
0,1-->0,05
=> \(m_{O_2}=0,05.32=1,6\left(g\right)\)
Bài 5:
Ta có: \(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\)
a, PT: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
_____0,2__0,25__0,1 (mol)
b, VO2 = 0,25.22,4 = 5,6 (l)
c, PT: \(P_2O_5+3H_2O\rightarrow2H_3PO_4\)
______0,1______________0,2 (mol)
\(\Rightarrow m_{H_3PO_4}=0,2.98=19,6\left(g\right)\)
\(\Rightarrow C\%_{H_3PO_4}=\dfrac{19,6}{120}.100\%\approx16,33\text{ }\%\)
Bạn tham khảo nhé!
a) \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
PTHH: 2Al + 3H2SO4 --> Al2(SO4)3 + 3H2
______0,2---->0,3------------>0,1------>0,3______(mol)
=> VH2 = 0,3.22,4= 6,72(l)
b) \(C_{M\left(H_2SO_4\right)}=\dfrac{0,3}{0,1}=3M\)
\(C_{M\left(Al_2\left(SO_4\right)_3\right)}=\dfrac{0,1}{0,1}=1M\)
Câu 3:
\(n_{H_2}=\dfrac{6,72}{22,4}=0,3(mol)\\ PTHH:Mg+2HCl\to MgCl_2+H_2\\ MgO+2HCl\to MgCl_2+H_2O\\ \Rightarrow n_{Mg}=n_{H_2}=0,3(mol)\\ \Rightarrow \%_{Mg}=\dfrac{0,3.24}{15,2}.100\%=47,37\%\\ \Rightarrow \%_{MgO}=100\%-47,37\%=52,63\%\)
\(n_{MgO}=\dfrac{15,2-0,3.24}{40}=0,2(mol)\\ \Rightarrow \Sigma n_{HCl}=0,3.2+0,2.2=1(mol)\\ \Rightarrow m_{dd_{HCl}}=\dfrac{1.36,5}{10\%}=365(g)\\ \Sigma n_{MgCl_2}=0,2+0,3=0,5(mol)\\ \Rightarrow C\%_{MgCl_2}=\dfrac{0,5.95}{15,2+365}.100\%=12,49\%\)
\(PTHH:Mg+2H_2SO_{4(đ)}\to MgSO_4+2H_2O+SO_2\uparrow\\ MgO+H_2SO_4\to MgSO_4+H_2O\\ \Rightarrow n_{SO_2}=n_{Mg}=0,3(mol)\\ \Rightarrow V_{SO_2}=0,3.22,4=6,72(l)\)
PT: \(2Al+3Cl_2\underrightarrow{t^o}2AlCl_3\)
\(AlCl_3+3AgNO_3\rightarrow Al\left(NO_3\right)_3+3AgCl\)
Ta có: \(n_{AgNO_3}=0,1.0,6=0,06\left(mol\right)\)
Theo PT: \(n_{Al}=n_{AlCl_3}=\dfrac{1}{3}n_{AgNO_3}=0,02\left(mol\right)\)
⇒ m = mAl = 0,02.27 = 0,54 (g)
\(C_{M_{AlCl_3}}=\dfrac{0,02}{0,15}=\dfrac{2}{15}\left(M\right)\)
\(a.2Al+6HCl\rightarrow2AlCl_3+3H_2\\ n_{AlCl_3}=\dfrac{13,35}{133,5}=0,1\left(mol\right)\\ TừPT:n_{Al}=n_{AlCl_3}=0,1\left(mol\right);n_{H_2}=\dfrac{3}{2}n_{AlCl_3}=0,15\left(mol\right)\\ \Rightarrow m_{Al}=0,1.27=2,7\left(g\right)\\ \Rightarrow V_{H_2}=0,15.22,4=3,36\left(l\right)\\ b.n_{HCl}=3n_{AlCl_3}=0,3\left(mol\right)\\ V_{ddHCl}=\dfrac{150}{1,12}=\dfrac{1875}{14}ml=\dfrac{15}{112}\left(l\right)\\ CM_{HCl}=\dfrac{0,3}{\dfrac{15}{112}}=2,24M\)
\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
PTHH:
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
0,2 0,2 0,2 0,2
\(a,\%m_{Fe}=\dfrac{0,2.56}{20}.100\%=56\%\)
\(\%m_{Cu}=100\%-56\%=44\%\)
\(b,C_{M\left(H_2SO_4\right)}=\dfrac{0,2}{0,1}=2\left(M\right)\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(1\) \(1\) \(1\)
\(0,2\) \(0,2\) \(0,2\)
\(n_{H_2}=\dfrac{V}{22,4}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
\(m_{Fe}=n.M=0,2.56=11,2\left(g\right)\)
\(^0/_0Fe=\dfrac{11,2}{20}.100^0/_0=56^0/_0\)
\(^0/_0Cu=100^0/_0-56^0/_0=44^0/_0\)
\(C_{M_{H_2SO_4}}=\dfrac{n}{V_{dd}}=\dfrac{0,2}{0,1}=2M\)
a)
PTHH: Mg + 2HCl --> MgCl2 + H2
0,075<--0,15--->0,075-->0,075
=> m = 0,075.24 = 1,8 (g)
b) VH2 = 0,075.22,4 = 1,68 (l)
c) mMgCl2 = 0,075.95 = 7,125 (g)
d)
PTHH: 2H2 + O2 --to--> 2H2O
0,075->0,0375
=> VO2 = 0,0375.22,4 = 0,84 (l)
a.b.c.
\(Mg+2HCl\rightarrow MgCl_2+H_2\)
0,075 0,15 0,075 0,075 ( mol )
\(m_{Mg}=0,075.24=1,8g\)
\(V_{H_2}=0,075.22,4=1,68l\)
\(m_{MgCl_2}=0,075.95=7,125g\)
d.\(2H_2+O_2\rightarrow\left(t^o\right)2H_2O\)
0,075 0,0375 ( mol )
\(V_{O_2}=0,0375.22,4=0,84l\)
1) nh2=0,2; n CACO3=0,7
pt1: CH4+2O2 ---> CO2+2H2O
x x
pt2: C2H4 +3O2 ----> 2CO2+2H2O
y 2y
pt3: CO2+CA(OH)2 ----> CACO3+H2O
0,7 0,7
ta có hệ pt: x+y=0,2
x+2y=0,7
tự tìm
b) nbr2=1
pt: C4H6+ 2Br2 -----> C4H6Br4
0,05 0,1 0,05
tỉ lệ: 0,3/1 > 0,1/2 => C4H6 dư
CM C4H6Br2=0,05/8,72
CM C4H6 dư= 0,25/8,72
\(n_P=\frac{m}{M}=\frac{3,1}{31}=0,1\left(mol\right)\)
\(PTHH:4P+5O_2\underrightarrow{t^o}2P_2O_5\)
(mol) 4 2
(mol) 0,1 0,05
\(PTHH:P_2O_5+3H_2O\rightarrow2H_3PO_4\)
(mol) 1 2
(mol) 0,05 0,1
\(C_{M_{H_3PO_4}}=\frac{n}{V}=\frac{0,1}{0,1}=1\left(M\right)\)
Theo pt ta thấy:
4P + 5O2 \(\underrightarrow{to}\) 2P2O5 (1)
P2O5 + 3H2O → 2H3PO4 (2)
\(n_P=\frac{3,1}{31}=0,1\left(mol\right)\)
Theo Pt1: \(n_{P_2O_5}=\frac{1}{2}n_P=\frac{1}{2}\times0,1=0,05\left(mol\right)\)
Theo Pt2: \(n_{H_3PO_4}=2n_{P_2O_5}=2\times0,05=0,1\left(mol\right)\)
\(\Rightarrow C_{M_{H_3PO_4}}=\frac{0,1}{0,1}=1\left(M\right)\)