physics and maths tutor
What apparatus is used in a titration to accurately measure volumes - answer- Burette
to measure the volume of solution added
- Pipette and pipette filler to measure a specific volume of solution into the conical flask
Describe the 'weighing-by-difference' method - answer- Add roughly the desired mass
of a substance to a weighing bottle and weigh - Transfer the substance to a beaker /
conical flask - Reweigh the weighing bottle - The difference between the masses is the
mass of solid
Describe how to carry out an acid-base titration - answer1. Use a pipette to add 25 cm3
of acid to a conical flask. Add a few drops of indicator.
2. Pour alkali into the burette. Record the initial burette volume.
3. Complete a trial titre. The conical flask should be swirled constantly above a white
tile. Stop adding the alkali as soon as the end point is reached. Record the final burette
volume.
4. Repeat the titration until two concordant results are obtained. Add alkali drop by drop
near the end point.
When transferring a solution from one beaker to another, how can you ensure as much
of the dissolved substance has been transferred as possible? - answerUse distilled
water to wash any leftover solution from the old apparatus into the new beaker
How do you accurately fill a volumetric flask to the graduated mark? - answerFill so the
bottom of the meniscus rests on the graduated mark. The meniscus is the curve of the
liquid
What is a standard solution? - answerA solution of a known concentration
Suggest 2 indicators that could be used in an acid-base titration - answer1.
Phenolphthalein 2. Methyl orange
State the colour of phenolphthalein in: a) Acidic conditions b) Basic conditions -
answera) Pink
b) Colourless
State the colour of phenolphthalein in: a) Acidic conditions b) Basic conditions -
answera) Pink
b) Colourless
What are concordant results in a titration? - answerTitres that are within 0.1 cm3 of
each other
What apparatus is used in a titration to accurately measure volumes - answer- Burette
to measure the volume of solution added
- Pipette and pipette filler to measure a specific volume of solution into the conical flask
Describe the 'weighing-by-difference' method - answer- Add roughly the desired mass
of a substance to a weighing bottle and weigh - Transfer the substance to a beaker /
conical flask - Reweigh the weighing bottle - The difference between the masses is the
mass of solid
Describe how to carry out an acid-base titration - answer1. Use a pipette to add 25 cm3
of acid to a conical flask. Add a few drops of indicator.
2. Pour alkali into the burette. Record the initial burette volume.
3. Complete a trial titre. The conical flask should be swirled constantly above a white
tile. Stop adding the alkali as soon as the end point is reached. Record the final burette
volume.
4. Repeat the titration until two concordant results are obtained. Add alkali drop by drop
near the end point.
When transferring a solution from one beaker to another, how can you ensure as much
of the dissolved substance has been transferred as possible? - answerUse distilled
water to wash any leftover solution from the old apparatus into the new beaker
How do you accurately fill a volumetric flask to the graduated mark? - answerFill so the
bottom of the meniscus rests on the graduated mark. The meniscus is the curve of the
liquid
What is a standard solution? - answerA solution of a known concentration
Suggest 2 indicators that could be used in an acid-base titration - answer1.
Phenolphthalein 2. Methyl orange
State the colour of phenolphthalein in: a) Acidic conditions b) Basic conditions -
answera) Pink
b) Colourless
State the colour of phenolphthalein in: a) Acidic conditions b) Basic conditions -
answera) Pink
b) Colourless
What are concordant results in a titration? - answerTitres that are within 0.1 cm3 of
each other
