Someone check my answer please. :)

[nesan]

1. The problem statement, all variables and given/known data

 

The rate of decomposition of hydrogen peroxide was studied at a particular temperature. H2O2(aq) = H2O (l) + 1/2O2(g)

 

The initial concentration of hydrogen

peroxide was 0.200 mol/L. 10.0 s later,

it was measured to be 0.196 mol/L.

 

b) 0.500 L of hydrogen peroxide solution was

used for the experiment. What mass was lost

as O2 bubbled out of solution in this initial

10.0 s interval?

 

2. The attempt at a solution

 

What I did was.

 

0.500 L * 0.200 mol/L = 0.1

 

0.500 L * 0.196 mol/L = 0.098

 

0.1 - 0.098 = 0.002mol

 

0.002 * 16 = 0.032 g

 

What I'm doubting is.

 

0.500 L * 0.196 mol/L = 0.098

 

Won't the volume change after 10 seconds?