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![](https://rs.olm.vn/images/avt/0.png?1311)
Đổi: 200ml = 0.2l; 300ml = 0.3l
nNaOH 1M = 0.2 x 1 = 0.2 (mol)
nNaOH 2M = 0.3 x 2 = 0.6 (mol)
nNaOH sau khi trộn = 0.2 + 0.6 = 0.8 (mol)
Vdd sau khi trộn = 200ml + 300ml = 500 ml = 0.5l
CMX = n/V = 0.8/0.5 = 8/5 = 1.6M
![](https://rs.olm.vn/images/avt/0.png?1311)
a)\(C\%=\dfrac{m_{ct}}{m_{dd}}\cdot100\%=\dfrac{5}{5+45}\cdot100\%=10\%\)
b)\(C\%=\dfrac{m_{ct}}{m_{dd}}\cdot100\%=\dfrac{5,6}{5,6+94,4}\cdot100\%=5,6\%\)
c)\(m_{ctNaOH}=\dfrac{200\cdot10\%}{100\%}=20g\)
\(m_{ctNaOH}=\dfrac{300\cdot5\%}{100\%}=15g\)
\(C\%=\dfrac{m_{ct}}{m_{dd}}\cdot100\%=\dfrac{20+15}{200+300}\cdot100\%=7\%\)
\(a,C\%_{NaOH}=\dfrac{5}{5+45}=10\%\)
b, \(n_{CaO}=\dfrac{5,6}{56}=0,1\left(mol\right)\)
PTHH: CaO + H2O ---> Ca(OH)2
0,1 ---------------> 0,1
\(\rightarrow C\%_{Ca\left(OH\right)_2}=\dfrac{74.0,1}{5,6+94,4}=37\%\)
c, \(m_{NaOH}=10\%.200+5\%.300=35\left(g\right)\)
\(\rightarrow C\%_{NaOH}=\dfrac{35}{200+300}=7\%\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a)m dd sau=100gam
mNaCl không đổi=80.15%=12 gam
C% dd NaCl sau=12/100.100%=12%
b)mdd sau=200+300=500 gam
Tổng mNaCl sau khi trộn=200.20%+300.5%=55 gam
C% dd NaCl sau=55/500.100%=11%
c) mdd sau=150 gam
mNaOH trg dd 10%=5 gam
mNaOH trong dd sau khi trộn=150.7,5%=11,25 gam
=>mNaOH trong dd a%=11,25-5=6,25 gam
=>C%=a%=6,25/100.100%=6,25% => a=6,25
![](https://rs.olm.vn/images/avt/0.png?1311)
nNaOH=0,05.2=0,1(mol);nNaOH=0,1.1,5=0,15(mol)
Vdd=100+50=150(ml)=0,15(l)
CM=(0,1+0,15)/0,15=1,67(M)
Ta có
n\(_{NaOH}=0,05.2=0,1\left(mol\right)\)
n\(_{NaOH\left(2\right)}=0,1.1,5=0,15\left(mol\right)\)
tổng n\(_{NaOH}=0,1+0,15=0,25\left(mol\right)\)
Tổng V\(_{NaOH}=0,05+0,1=0,15\left(l\right)\)
C\(_M=\frac{0,25}{0,15}=\)1,67(M)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(m_{NaOH}=150\cdot20\%+220\cdot15\%=63\left(g\right)\)
\(C\%_{NaOH}=\dfrac{63}{150+220}\cdot100\%=17.02\%\)
Để : thu được dung dịch NaOH 30%
\(m_{NaOH\left(tv\right)}=a\left(g\right)\)
\(C\%_{NaOH\left(30\%\right)}=\dfrac{63+a}{370+a}\cdot100\%=30\%\)
\(\Rightarrow a=68.57\left(g\right)\)
- Áp dụng phương pháp đường chéo :
\(\Rightarrow\dfrac{150}{220}=\dfrac{x-15}{20-x}\)
=> x = 17%
- Áp dụng phương pháp đường chéo :
=> x = 68,7g
Vậy ...
ai giai gium minh coi ? :3