Tests for cations

Created by

Ashley mak

Cards (18)

Cation
Positively charged ion
2 tests that can be used for identifying ions
Flame test
Flame emission spectroscopy
Flame test
A method of identifying metal ions by seeing what colour flame they produce when they burn
Steps required to perform a flame test
Take a platinum wire loop and clean it by dipping it in some dilute hydrochloric acid, rinsing it in distilled water, and then heating it over a Bunsen burner flame
Dip the wire loop into the compound you want to test
Hold the wire loop in the clear blue part of the Bunsen burner flame
See what colour the flame turns as the compound burns
What colour will lithium ions burn with
Crimson
What colour will sodium ions burn with
Yellow
What colour will potassium ions burn with
Lilac
What colour will calcium ions burn with
Orange-red
What colour will copper ions burn with
Green
Why does the flame test not work very well if the sample contains multiple metals
The different flame colours will mask eachother
Why should the wire be clean for a flame test
No impurities which could alter the colour
How do you test metals using sodium hydroxide
Add sodium hydroxide to the muster compound. The colour change will indicate which metal is in the compound
When performing the sodium hydroxide test for metal ions, what is the colour of the calcium precipitate
White
When performing the sodium hydroxide test for metal ions, what is the colour of the copper precipitate
Blue
When performing the sodium hydroxide test for metal ions, what is the colour of the Fe2+ precipitate
Green
When performing the sodium hydroxide test for metal ions, what is the colour of the Fe3+ precipitate
Brown
When performing the sodium hydroxide test for metal ions, what is the colour of the aluminium precipitate
White at firm then redissolves in excess sodium hydroxide to form a colourless solution
When performing the sodium hydroxide test for metal ions, what is the colour of the magnesium precipitate
White