Methodology for Chemical Analysis 2
Chemistry: AQA GCSE Higher, topic 8.3.9
Flame Emission Spectroscopy
Flame emission spectroscopy is an instrumental method of identifying metal ions in a solution and their concentrations. This method has advantages and disadvantages compared to traditional methods:
Advantages
- More sensitive and accurate.
- Quicker at producing results.
- Able to analyse small samples.
Disadvantages
- The instruments are often expensive.
- You need to go through special training to operate the instruments.
- The results are often only useful when compared to data from known substances.
Spectroscopy process
- Place a sample of a metal solution into a flame. Light is emitted.
- The light that is emitted is captured by a spectroscope.
- This instrument can distinguish between different wavelengths of light to produce a line spectrum.
Spectroscopy analysis
- We can analyse the line spectra produced by flame emission spectroscopy to see which metal ions are present.
- We can use the data to work out the concentration of the metal ions.
Identifying metal ions
- Each metal ion will generate a distinct line spectrum. This means that we can identify all ions present in a solution.
- The intensity of line spectra gives information about the concentration of an ion.
Reference spectra
- Unlike flame tests, flame emission spectroscopy allows us to analyse mixtures by comparing them with reference spectra.
Test yourself on Methodology for Chemical Analysis 2
In a line spectrum from flame emission spectroscopy, what do you need to look at to understand the concentration of an ion?
In a line spectrum from flame emission spectroscopy, what do you need to look at to understand what metal ions are present in the sample?
Select the true statement in each pair