Answer:
[tex]0.15\frac{mol}{g}[/tex]
Explanation:
The first step is to calculate the total amount of moles of HCl, so:
[tex]500 mL = 0.5 L\\\\M=\frac{mol}{L} \\\\\\mol=0.5L*0.1M=0.05 mol~ HCl[/tex]
Then we can calculate the moles of HCl consumed in the reaction of NaOH:
[tex]HCl~ +~ NaOH~ ->~ NaCl~ +~ H_2O[/tex]
[tex]39.5~mL=~0.0395~L\\\\mol~=~0.0395L*0.098M=~0.0038~mol~NaOH\\\\0.0038~mol~NaOH=~0.0038~mol~HCl[/tex]
Then we have to substract from the intial value to obtain the moles of HCl that react with the sample:
[tex]0.05-0.0038=0.0461~mol~HCl[/tex]
Finally to know the ratio between grams and moles we have to divide:
[tex]\frac{0.0461~mol}{0.29~g}[/tex]
[tex]0.15\frac{mol}{g}[/tex]
