8D.2 Flashcards
what is titration
it is a practical method with the aim of measuring volumes of two solutions that react together, and then using that value to then find the concentration of one of the solutions
what are acid alkali tirtrations
they are titrations between acid and soluble bases
the colour of the acids and the alkalis are??
colourless in this method
what is the outline of the acid-alkali titration method
- add the acid to the alkali until the equivalence point and when the indicator has reached its endpoint
- you are going to record the burette reading using the lowest part of the meniscus
- calculate the titrate
- repeat the experiment until coordinate results are reached
what is the equivalence point
the point where there is the right amount of substance to complete a reaction
what is the endpoint
the point where the indicator changes colour. ideally, it should consider the equivalence point
what is a meniscus
the curving of the upper surface of a liquid and you should take a reading from the lowest (horizontal) part of it
what is the titrate
the volume added from the burette doing titrations
what are concordant results
two titrates that are very close to each other within a 0.2 diff
what is the method of acid-alkalis titrations
page 220
what is the apparatus used in the acid-alkalis titrations
pages 220
why is a white tile use
to see the colour change more clearly
why do we add 3 drops of indicator
each indicator used in an acid-alkalis base is a week acid, using it will have an effect on the endpoint of titrations, so it is important to use the same and little volume each time for more accurate results
why do we fill the space between the tap and the tip and the burette
if this is not done and we turn on the tap some of the liquid will fill the space and won’t enter the conical flask so we won’t have an accurate titrate at the end
why do we set up the burette so its tip is in the conical flask
so we would minimize the risk of some of the acid going outside the conical flask
why do we read the burette to the nearest half 0.05 cm at the bottom of the meniscus
to increase the accuracy of the reading
why do we add the NH2SO3H steadily into the conical flask then while approaching the endpoint we start adding slowly
to make sure not to overshoot the endpoint
why are we always swirling the conical flask
to make sure that the two solutions are always mixing
why would we repeat the experiment till we get concordant results
to increase the accuracy
why do why not rinse the conical flask with both the solution and the distilled water
because then we would have an unknown extra amount of sodium being titrated that we don’t know about
whta are the two common indicators used in an acid-alkali titration
- methyl orange
2. phenolphthalein
what is the colour of methyl orange in acid
red
what is the colour of phenolphthalein in acid
colourless
what is the colour of methyl orange in alkali
yellow
