Flame test + photometry - SC25 Flashcards
What are the steps for the flame test?
- light a bunsen burner on a blue flame
- use a nichrome or platinum wire loop cleaned in HCL
- Pick up small sample of the test substance using wire loop
- hold sample in edge of flame and observe flame colour and record
What colour does lithium go in the flame?
red
what colour does sodium go in the flame?
yellow
what colour does potassium go in the flame?
lilac
what colour does calcium go in the flame?
orange-red
what colour does copper go in the flame?
blue-green
what is the symbol for lithium?
Li+
what is the symbol for calcium?
Ca2+
what symbol is copper?
Cu2+
what symbol is potassium?
K+
what symbol is sodium?
Na+
what metal ion turns blue-green in flame?
copper
what metal ion turns lilac in flame?
potasium
what metal ion turns orange-red in flame?
calcium
what metal ion turns yellow in flame?
sodium
what metal ion turns red in flame?
lithium
what does flame photometry measure?
light intensity of the flame colours produced by metal ions?
why are scientific instruments a benefit in flame photometry? what do they improve and why?
improve sensitivity as they can detect smaller amounts
improve accuracy as they give values closer to the true values
improve speed of results
how is photometry data used?
determine concentration of a metal ion in a dilute solution
how is a calibration curve produced?
using different standard solutions each containing known concentrations of the metal ion dissolved in distilled water
what is true about all elements used in the flame test?
they are metal ions
how does a falme photometer seperate out mixtures of colours seen using flame test?
producing a sprectrum of the light emitted by each metal ion as different metal ions produce different emission spectra
how can a metal ion in an unknown soultion be identified?
by matching and comparing its spectra against the spectrum for known metal ions
