calculate the volume of the equation. Chemistry help

Question

 

calculate the volume (in mL) of 0.025 M KMnO4 solution needed to completely react with 10.0 mL of advertised 3% by mass H2O2 solution in the presence o excess acid. Assume that the density of the 3% H2O2 solution is 1.00 g/mL.

 

 

2MnO_{4 (aq)} + 5H₂O_{2 (aq)} + 6H₃O_(aq) ---> 2Mn_(aq) + 5O_{2 (g)} + 14H₂O_(l)

Answer 1

3% peroxide = 3 g/100ml

3 g/100 ml x 10 ml = 0.3 g H2O2

0.3 g H2O2 x 1 mole/34 g = 0.0088 moles

0.0088 moles H2O2 x 2 moles MnO4/5moles H2O2 = 0.00353 moles MnO4 needed

0.025 mol/L (x L) = 0.00353 moles

x = 0.141 L = 141 mls