→ mHBr = 15,625 x 81 = 1265,625g;

VH2O = 1 lít ⇒ mH2O = 1000g.

n_HBr = 350 / 22,4 = 15,625 mol.

m_HBr = 15,625 x 81 = 1265,625g.

C%_HBr = 1265,625 x 100% / (1000 + 1265,625) \(\approx\) 55,86%.

Bài 1:

\(2Na+2H_2O\rightarrow2NaOH+H_2\\ n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\\ n_{Na}=n_{Na_2O}=0,2.2=0,4\left(mol\right)\\ a.m_{Na}=0,4.23=9,2\left(g\right)\\ b.C_{MddA}=\dfrac{0,4}{0,5}=0,8\left(M\right)\\ C\%_{ddA}=\dfrac{0,4.40}{500.1,2}.100\approx2,667\%\)

\(K+H_2O\rightarrow KOH+\dfrac{1}{2}H_2\)

\(n_K=2n_{H_2}=0,2\left(mol\right)\Rightarrow m_K=7,8\left(g\right)\)

=> \(m_{K_2O}=17,2-7,8=9,4\Rightarrow n_{K_2O}=0,1\left(mol\right)\)

\(K_2O+H_2O\rightarrow2KOH\)

\(\Sigma n_{KOH}=0,2+0,1.2=0,4\left(mol\right)\)

\(m_{ddsaupu}=17,2+600-0,1.2=617\left(g\right)\)

=> \(C\%_{KOH}=\dfrac{0,4.56}{712}.100=3,15\%\)

${H2O}$

\(n_{H_2S}=\dfrac{16,8}{22,4}=0,75\left(mol\right)\\\rightarrow m_{H_2S}=0,75.34=25,5\left(g\right)\\ m_{dd}=25,5+174,5=200\left(g\right)\\ \rightarrow C\%_{H_2S}=\dfrac{25,5}{200}.100\%=12,75\%\)

nH2 = 0.115 (mol) 

2A + 2nH2O => 2A(OH)n + nH2  

0.23/n__________________0.115 

M_A = 8.97/0.23/n = 39n

BL : n = 1 => A = 39 

A là : Kali 

mKOH = 0.23*56 =12.88 (g) 

mdd thu được = 8.97 + 100 - 0.115*2 = 108.74(g) 

C% KOH = 12.88/108.74 *100% = 11.84(g) 

c) 

nCO2 = 3.36/22.4 = 0.15 (mol) 

nKOH / nCO2 = 0.23/0.15 = 1.53 

=> tạo ra 2 muối 

Đặt : 

nK2CO3 = a (mol) 

nKHCO3 = b (mol) 

2KOH + CO2 => K2CO3 + H2O 

KOH + CO2 => KHCO3 

nKOH = 2a + b = 0.23 

nCO2 = a +b = 0.15 

=>a = 0.08

b = 0.07 

mK2CO3 = 0.08*138 = 11.04 (g) 

mKHCO3 = 100* 0.07 = 7 (g) 

Đơn vị của C% là gam có đúng k ạ

PTHH: \(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)

            \(Al_2O_3+6HCl\rightarrow2AlCl_3+3H_2O\)

a) Ta có: \(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)=n_{Zn}\)

\(\Rightarrow\%m_{Zn}=\dfrac{0,4\cdot65}{36,2}\cdot100\%\approx71,23\%\) \(\Rightarrow\%m_{Al_2O_3}=28,77\%\)

c) Ta có: \(n_{Al_2O_3}=\dfrac{36,2-0,4\cdot65}{102}=0,1\left(mol\right)\)

Theo PTHH: \(n_{HCl}=2n_{Zn}+6n_{Al_2O_3}=1,4\left(mol\right)\)

\(\Rightarrow m_{ddHCl}=\dfrac{1,4\cdot36,5}{10\%}=511\left(g\right)\) \(\Rightarrow V_{ddHCl}=\dfrac{511}{1,1}\approx464,5\left(ml\right)=0,4645\left(l\right)\)

c) Theo PTHH: \(\left\{{}\begin{matrix}n_{ZnCl_2}=0,4\left(mol\right)\\n_{AlCl_3}=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}C_{M_{ZnCl_2}}=\dfrac{0,4}{0,4645}\approx0,86\left(M\right)\\C_{M_{AlCl_3}}=\dfrac{0,2}{0,4645}\approx0,43\left(M\right)\end{matrix}\right.\)