Calculate the rate please

[Chemist98]

The reaction is:

Volume of 6% H2O2 (mL):8.0

Volume of distilled water (mL):2.0

Volume of 1.0 M NaI (mL):10.0

Volume of distilled water (mL):0.0

O2 production in 60 s (mL):93.0

 

 

Question: Calculate the change in hydrogen peroxide concentration per second. This is the rate. (Hint: What volume of liquid does the hydrogen peroxide now occupy?).

 

How would I do this?

[CaptainPanic]

The only thing you know about the rate is the oxygen production: 93.0 mL / 60 s

 

The reaction that gives the oxygen is:

 

2 H2O2 --> 2 H2O + O2

 

So, you need to calculate the amount of moles of oxygen produced. Then you know the amount of moles of peroxide that are reacting away... which is the answer you need.

[Chemist98]

Was yoour answer 0.02421875 mol/l s?

 

Just want to make sure Im on the right track

[hermanntrude]

two points:

 

1) you have two data which you labelled "volume of distilled water", one of which is 2 mL and one is 0.0 mL. Which is it?

 

2) the question is badly worded, since it tells you that the rate of the reaction is the change in concentration of the hydrogen peroxide per second. The IUPAC reccomendation for measurement of rates is the negative of the change in concentration of a reactant divided by the stoichiometric coefficient. In other words, the change in concentration of hydrogen peroxide is actually negative of a double the rate, not the rate itself.

 

to find the rate of decomposition of hydrogen peroxide, divide the change in concentration by the time. If you want the answer in moles/litre/second, divide by seconds instead of minutes.