Enzyme Prac

[judygee]

Dear Chemtalk Family - Just finished the enzyme prac using Potatoes & Hydrogen peroxide. We were happy with the temperatures and substrate results however the pH results were'nt as expected! We were looking at pH 3, 6, 8, 11. pH 11 excellent - but pH 3, 6, & 8 the bubbles were the same height!!!! I used 6% H2O2 straight from the bottle for the pH 3 & 1 drop of 2M KOH for pH 6 and 20 drops of 2M KOH for the pH 8 Going through the previous threads on this topic I notice for the pH 6 using 0.1M NaOH is recommended, & then 2M for the pH 8 & 11. Would this have made a difference to our results do you think? And if so Why? Also do prepared Buffer solutions go "OFF" within a certain period?

[rp]

Hi
yes the buffers do go off.Mine did.
Check use by date on bottle
Hope this helps
Rhonda