Required practicals Flashcards
What is the method for a simple titration?
-wash all apparatus with water, and the pipette with sodium hydroxide
-use a pipette and pipette filler to measure out 25cm3 of sodium hydroxide, then place it in a conical flask with 3 drops of indicator
-rinse burette with acid and then fill it with a funnel up to just above 0cm3
-let out a little bit of acid until the bottom of the meniscus is on the 0cm3 mark
-place the conical flask under the burette and let out around 20cm3 of acid while swirling
-add dropwise when a colour change starts to occur
-record the results and repeat until you have concordant results
Why should you remove the funnel?
to stop the acid from dripping into the burette- results in a lower volume as the acid replaces some of the air
Why does it not matter if the conical flask has drops of water?
water doesn’t affect the moles of acid/alkali
Why should we remove all air bubbles from the burette jett?
some of the solution would fill the space where the air bubbles were and not go in the conical flask-results in the volume recorded being greater than in reality
