Chemical Analysis Flashcards
What is chromatography?
A method used to separate the components present within a mixture
What are 3 methods of chromatography?
- Paper chromatography
- Thin layer chromatography
- Gas liquid chromatography
In thin layer chromatography, the identity of a component can be indicated by what?
By the distance it has travelled, or by the time it has taken to travel through
the apparatus (retention time)
The results of a chromatography experiment can sometimes be presented graphically,
What does the y-axis usually indicate?
The quantity of a substance
The results of a chromatography experiment can sometimes be presented graphically,
What does the x-axis usually indicate?
The retention time
What is volumetric analysis used for?
To determine the concentration of another substance using a solution of accurately known concentration
What is a standard solution?
A solution of accurately known concentration
How do you make a standard solution?
- Weigh the required mass into a beaker
- Add half of the final volume of de-ionised water into the beaker and stir until the solid is fully dissolved
- Pour the solution into a volumetric flask
- Add a small volume of de-ionised water into the beaker and rinse it. Pour the washings into the volumetric flask and repeat twice
- Fill the volumetric flask with de-ionised water until the volume reaches the mark
- Invert the flask multiple times
What is titration used for?
To determine the volumes of solution required to reach the end-point of a reaction
What does concordant mean?
When titre volumes are within 0.2cm3 of each other
Why is Permanganate used as an indicator?
Because it is self-indicating and changes colour of the solution when the end-point is met
Why does permanganate have to be acidified?
To supply H+ ions to allow the reduction equation to occur
What are some possible sources of error in titration?
- Misjudging the colour of the indicator near the end-point
- Using contaminated solutions
- Misreading the volume
- Using contaminated apparatus
