\(V_{tb}=\dfrac{s_1+s_2}{t_1+t_2}=\dfrac{4+2}{6+6}=0,5\left(m/s\right)\)

 4Na + O₂ -----t^o→ 2Na₂O

 Na₂O + CO₂ ---t^o→ Na₂CO₃

 Na₂CO₃ + H₂SO₄ → Na₂SO₄ + CO₂ + H₂O

 Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl

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Ta có: \(d_{B/O_2}=\dfrac{M_B}{M_{O_2}}=0,5\Rightarrow M_B=0,5.32=16\left(g/mol\right)\)

Ta có: \(d_{A/B}=\dfrac{M_A}{M_B}=2,125\Rightarrow M_A=2,125.16=34\left(g/mol\right)\)

\(\Leftrightarrow\left(x+2\right)^3=64\Leftrightarrow x+2=4\Leftrightarrow x=2\)

a, \(n_{NaOH}=0,1.1,5=0,15\left(mol\right)\)

PTHH: NaOH + HCl → NaCl + H₂O

Mol:       0,15      0,15     0,15

\(V_{ddHCl}=\dfrac{0,15}{0,5}=0,3\left(l\right)\)

b, \(C_{M_{ddNaCl}}=\dfrac{0,15}{0,1+0,3}=0,375M\)

PTHH: Mg + 2HCl → MgCl₂ + H₂

Ta có: \(m_{Mg}+m_{HCl}=m_{MgCl_2}+m_{H_2}\)

    \(\Leftrightarrow m_{MgCl_2}=m_{Mg}+m_{HCl}-m_{H_2}=2,4+7,3-0,2=9,5\left(g\right)\)

x tỉ lệ thuận với y theo hệ số tỉ lệ \(\dfrac{1}{k}=2\)