Chemistry 3 Chemistry in action/C3: Topic 1-Qualitative analysis/C3.1 Water testing
- Created by: Daniel2014
- Created on: 17-05-13 18:04
Fullscreen
- Food is tested for purity and safety in chemical analysis.
- Qualitative analysis checks the type of substances in the sample.
- Quantitative analysis measures the amount of the substances in the sample.
- Water sometimes contains ionic compounds which are made of cations and anions.
- An analyst must test for each ion to identify an unknown ionic compound. Both anion and cation must be identified.
- Ion tests must only give one positive result to identify the compound.
- Flame tests can detect some cations.
Calcium:
- Symbol: Ca2+
- Flame colour: Brick red
Sodium:
- Symbol: Na+
- Flame colour: Yellow
Potassium:
- Symbol: K+
- Flame colour: Lilac
Copper:
- Symbol: Cu2+
- Flame colour: Green/Blue
- Sodium hydroxide can be added to the solution to find the unknown cations
- Many metal hydroxides are insoluble so a precipitation reaction can occur.
- The precipitate formed can identify the ion.
Aluminium:
- Symbol: Al3+(aq)
- Effect: White precipitate
Calcium:
- Symbol: Ca2+(aq)
- Effect…
Comments
No comments have yet been made