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Bài 1:
a, PT: \(Na_2O+H_2O\rightarrow2NaOH\)
b, Ta có: \(n_{Na_2O}=\dfrac{31}{62}=0,5\left(mol\right)\)
\(n_{H_2O}=\dfrac{27}{18}=1,5\left(mol\right)\)
Xét tỉ lệ: \(\dfrac{0,5}{1}< \dfrac{1,5}{1}\), ta được H2O dư.
Theo PT: \(n_{NaOH}=2n_{Na_2O}=1\left(mol\right)\)
\(\Rightarrow m_{NaOH}=1.40=40\left(g\right)\)
b, Theo PT: \(n_{H_2O\left(pư\right)}=n_{Na_2O}=0,5\left(mol\right)\)
\(\Rightarrow n_{H_2O\left(dư\right)}=1,5-0,5=1\left(mol\right)\)
\(\Rightarrow m_{H_2O\left(dư\right)}=1.18=18\left(g\right)\)
Bài 2:
a, PT: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
Ta có: \(n_{CH_4}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
\(n_{O_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
b, Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,15}{2}\), ta được CH4 dư.
Theo PT: \(n_{CH_4\left(pư\right)}=\dfrac{1}{2}n_{O_2}=0,075\left(mol\right)\)
\(\Rightarrow n_{CH_4\left(dư\right)}=0,1-0,075=0,025\left(mol\right)\)
\(\Rightarrow V_{CH_4\left(dư\right)}=0,025.22,4=0,56\left(l\right)\)
c, Theo PT: \(\left\{{}\begin{matrix}n_{CO_2}=\dfrac{1}{2}n_{O_2}=0,075\left(mol\right)\\n_{H_2O}=n_{O_2}=0,15\left(mol\right)\end{matrix}\right.\)
⇒ m sản phẩm = mCO2 + mH2O = 0,075.44 + 0,15.18 = 6 (g)
Bài 1:
\(a,2Cu+O_2\underrightarrow{t^o}2CuO\)
b, \(n_{O_2}=\dfrac{1,12}{32}=0,035mol\)
\(n_{Cu}=\dfrac{6,4}{64}=0,1mol\)
\(\dfrac{0,1}{2}>\dfrac{0,035}{1}\) => Cu dư, O2 đủ
\(n_{Cu}\left(dư\right)=0,1-0,07=0,039\left(mol\right)\)
c, \(m_{CuO}=0,07.80=5,6g\)
Bài 2:
\(n_{Al}=\dfrac{13,5}{27}=0,5mol\)
\(n_{O_2}=\dfrac{6,67}{32}=0,21\left(mol\right)\)
\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
\(\dfrac{0,5}{4}>\dfrac{0,21}{3}\) => Al dư, O2 đủ
\(n_{Al_2O_3}=\dfrac{2}{3}.0,21=0,14\left(mol\right)\)
\(m_{Al_2O_3}=0,14.102=14,28g\)
\(n_{Fe}=\dfrac{12.6}{56}=0.225\left(mol\right)\)
\(n_{O_2}=\dfrac{4.2}{22.4}=0.1875\left(mol\right)\)
\(3Fe+2O_2\underrightarrow{^{^{t^0}}}Fe_3O_4\)
\(3.........2\)
\(0.225......0.1875\)
Lập tỉ lệ : \(\dfrac{0.225}{3}< \dfrac{0.1875}{2}\Rightarrow O_2dư\)
\(m_{O_2\left(dư\right)}=\left(0.1875-0.225\cdot\dfrac{2}{3}\right)\cdot32=1.2\left(g\right)\)
\(m_{Fe_3O_4}=\dfrac{0.225}{3}\cdot232=17.4\left(g\right)\)
a, PTHH: S + O2 -> (t°) SO2
b, nS = 6,4/32 = 0,2 (mol)
nO2 = 6,72/22,4 = 0,3 (mol)
LTL: 0,2 < 0,3 => O2 dư
nO2 (pư) = nSO2 = nS = 0,2 (mol)
mO2 (dư) = (0,3 - 0,2) . 32 = 3,2 (g)
c, mSO2 = 64 . 0,2 = 12,8 (g)
a, \(S+O_2\underrightarrow{t^o}SO_2\)
\(nS=\dfrac{6,4}{32}=0,2\left(mol\right)\)
\(nO_2=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
\(\dfrac{0,2}{1}< \dfrac{0,3}{1}\) => oxi dư
\(nO_{2\left(dư\right)}=0,1\left(mol\right)\)
\(mO_{2\left(dư\right)}=0,1.32=3,2\left(g\right)\)
\(nSO_2=nS=0,2\left(mol\right)\)
\(mSO_2=0,2.64=12,8\left(g\right)\)
a) 2H2 + O2 --to--> 2H2O
b) \(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
PTHH: 2H2 + O2 --to--> 2H2O
0,1-->0,05------>0,1
=> mH2O = 0,1.18 = 1,8 (g)
c) \(n_{O_2\left(bđ\right)}=\dfrac{1,344}{22,4}=0,06\left(mol\right)>n_{O_2\left(pư\right)}=0,05\left(mol\right)\)
=> O2 dư
nO2(dư) = 0,06 - 0,05 = 0,01 (mol)
VO2(dư) = 0,01.22,4 = 0,224 (l)
\(n_{Al}=\dfrac{0,54}{27}=0,02\left(mol\right)\)
\(n_{Cl2\left(dktc\right)}=\dfrac{0,896}{22,4}=0,04\left(mol\right)\)
a) Pt : \(2Al+3Cl_2\underrightarrow{t_o}2AlCl_3|\)
2 3 2
0,02 0,04 0,04
Lập tỉ số so sánh : \(\dfrac{0,02}{2}< \dfrac{0,04}{3}\)
⇒ Al phản ứng hết , Cl2 dư
⇒ Tính toán dựa vào số mol của Al
b) \(n_{AlCl3}=\dfrac{0,02.2}{2}=0,02\left(mol\right)\)
⇒ \(m_{AlCl3}=0,02.133,5=2,67\left(g\right)\)
\(n_{Cl2\left(dư\right)}=0,04-\left(\dfrac{0,02.3}{2}\right)=0,01\left(mol\right)\)
⇒ \(m_{Cl2}=0,01.71=0,71\left(g\right)\)
Chúc bạn học tốt
\(a,PTHH:Zn+2HCl\to ZnCl_2+H_2\\ b,n_{Zn}=\dfrac{13}{65}=0,2(mol)\)
Vì \(\dfrac{n_{Zn}}{1}>\dfrac{n_{HCl}}{2}\) nên Zn dư
\(\Rightarrow n_{Zn({\text{phản ứng})}}=\dfrac{1}{2}n_{HCl}=0,15(mol)\\ \Rightarrow n_{Zn(\text{dư})}=0,2-0,15=0,05(mol)\\ \Rightarrow m_{Zn(\text{dư})}=0,05.65=3,25(g)\\ c,n_{ZnCl_2}=n_{H_2}=\dfrac{1}{2}n_{HCl}=0,15(mol)\\ \Rightarrow a=m_{ZnCl_2}=0,15.136=20,4(g)\\ V=V_{H_2}=0,15.22,4=3,36(l)\)
PTHH: \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
Ta có: \(\left\{{}\begin{matrix}n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\\n_{O_2}=\dfrac{12,8}{32}=0,4\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,2}{3}< \dfrac{0,4}{2}\) \(\Rightarrow\) Oxi còn dư, Fe p/ứ hết
\(\Rightarrow n_{O_2\left(dư\right)}=0,4-\dfrac{2}{15}=\dfrac{4}{15}\left(mol\right)\)
+) Theo PTHH: \(\left\{{}\begin{matrix}n_{O_2}=\dfrac{2}{15}\left(mol\right)\\n_{Fe_3O_4}=\dfrac{1}{15}\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}V_{kk}=\dfrac{2}{15}\cdot22,4\cdot5\approx14,93\left(l\right)\\m_{Fe_3O_4}=\dfrac{1}{15}\cdot232\approx15,47\left(g\right)\end{matrix}\right.\)
a) \(n_{H_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)
\(n_{O_2}=\dfrac{10,08}{22,4}=0,45\left(mol\right)\)
PTHH: 2H2 + O2 --to--> 2H2O
Xét tỉ lệ: \(\dfrac{0,5}{2}< \dfrac{0,45}{1}\) => H2 hết, O2 dư
PTHH: 2H2 + O2 --to--> 2H2O
0,5-->0,25----->0,5
=> \(m_{O_2\left(dư\right)}=\left(0,45-0,25\right).32=6,4\left(g\right)\)
b) \(m_{H_2O}=0,5.18=9\left(g\right)\)
c)
PTHH: 2KMnO4 --to--> K2MnO4 + MnO2 + O2
0,5<-----------------------------------0,25
=> \(m_{KMnO_4}=0,5.158=79\left(g\right)\)
