Respuesta :
Answer : The mass of [tex]Na_2SO_4[/tex] is, 4.43 grams.
Explanation :
As we know that, when [tex]Na_2SO_4[/tex] dissolve in water then it dissociates to give 2 mole of sodium ion [tex]Na^+[/tex] and 1 mole of sulfate ion [tex]SO_4^{2-}[/tex]
The chemical reaction will be:
[tex]Na_2SO_4\rightarrow 2Na^++SO_4^{2-}[/tex]
Thus, the concentration of [tex]Na_2SO_4[/tex] = [tex]\frac{\text{Concentration of }Na^+}{2}=\frac{0.125M}{2}=0.0625M[/tex]
First we have to calculate the moles of [tex]Na_2SO_4[/tex]
[tex]\text{Concentration of }Na_2SO_4=\frac{\text{Moles of }Na_2SO_4}{\text{Volume of solution}}[/tex]
[tex]0.0625M=\frac{\text{Moles of }Na_2SO_4}{0.500L}[/tex]
[tex]\text{Moles of }Na_2SO_4=0.0312mol[/tex]
Now we have to calculate the mass of [tex]Na_2SO_4[/tex]
[tex]\text{Mass of }Na_2SO_4=\text{Moles of }Na_2SO_4\times \text{Molar mass of }Na_2SO_4[/tex]
Molar mass of [tex]Na_2SO_4[/tex] = 142 g/mol
[tex]\text{Mass of }Na_2SO_4=0.0312mol\times 142g/mol=4.43g[/tex]
Thus, the mass of [tex]Na_2SO_4[/tex] is, 4.43 grams.
