Bạn tham khảo!
$\text{a) We have the following chemical equation:}$
$\text{Na2O+H2O$\rightarrow$2NaOH}$
$\text{b) The moles of Na2O:}$
$\text{n=$\frac{m}{M}$=$\frac{3,2}{62}$=0,05 moles}$
$\text{Based on the chemical equation we have:}$
$\rightarrow$ $\text{nNaOH=2nNa2O=0,05.2=0,1 moles}$
$\text{Because the volume of NaOH= the volume of H2O}$
$\rightarrow$ $\text{VNaOH=750ml}$
$\text{Convert 750ml to 0,75 liters}$
$\text{The molarity of NaOH:}$
$\text{CM=$\frac{n}{V}$=$\frac{0,1}{0,75}$=0,13M}$
$\text{c)The mass of NaOH:}$
$\text{m=n.M=0,1.40=4g}$
$\text{Based on the formula: CM=$\frac{10.D.C}{M}$}$
$\rightarrow$ $\text{C%=$\frac{M.CM}{10.D}$ }$
$\text{C%=$\frac{40.0,13}{10.1}$=0,52% }$
#TRANPHAMGIABAO
