Answer:
3.35 g Na2C2O4
Explanation:
They gave us the molarity and the liters of solution so using the relationship (M=mol/V) we can get the moles of solution.
0.250 L (0.100 mol/L) = 0.0250 mol Na2C2O4
Now that we have the moles of sodium oxalate, we can use its molar mass (134 g/mol) to convert to grams.
0.0250 mol (134.0 g/mol) -=3.35 grams (rounded to three sig figs