b)Từ lượng rượu etylic thu được ở trên pha thành V ml cồn 75°. Tính V

* Hướng dẫn giải

b)

 ${\text{n}}_{{\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}}\text{\hspace{0.17em}\hspace{0.17em}=\hspace{0.17em}\hspace{0.17em}}\frac{\text{m}}{\text{120}}\text{\hspace{0.17em}\hspace{0.17em}=\hspace{0.17em}\hspace{0.17em}}\frac{\text{90}}{\text{120}}\text{\hspace{0.17em}\hspace{0.17em}=\hspace{0.17em}\hspace{0.17em}0,75(mol)}$

${\text{m}}_{{\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}}\text{ =\hspace{0.17em}\hspace{0.17em}0,75.46\hspace{0.17em}\hspace{0.17em}=\hspace{0.17em}\hspace{0.17em}34,5gam}$

${\text{V}}_{ruounguyenchat}\text{=\hspace{0.17em}\hspace{0.17em}}\frac{\text{34,5}}{\text{0,8}}\text{\hspace{0.17em}\hspace{0.17em}=\hspace{0.17em}\hspace{0.17em}43,125ml}$

$V_{ddruou}=\frac{43,125}{75\%}=57,5ml$