OBHB - Module 3.1 Flashcards
(17 cards)
How do you conduct a flame test?
Clean nichrome wire loop with acid to remove impurities; scoop up solid sample of salt; put wire loop in the centre of a blue Bunsen flame.
What is lithium’s flame test colour?
Red
What is sodium’s flame test colour?
Yellow
What is potassium’s flame test colour?
Lilac
What is magnesium’s flame test colour?
Bright white
What is calcium’s flame test colour?
Brick red
What is strontium’s flame test colour?
Crimson
What is barium’s flame test colour?
Apple green
What is the test for ammonium ions?
Add sodium hydroxide and heat, creating fumes which turn damp red litmus paper blue.
What are the tests for halide ions?
Add nitric acid, then silver nitrate.
Add dilute and concentrated ammonia.
What are the results of the halide tests for chloride ions?
White precipitate
Soluble in both
What are the results of the halide tests for bromide ions?
Cream precipitate
Soluble in conc. but only slightly soluble in dilute
What are the results of the halide tests for iodide ions?
Yellow precipitate
Not soluble in either
What is the test for carbonate ions?
Add an acid and a gas is produced which turns limewater cloudy.
What is the test for sulfate ions?
Add hydrochloric acid then a soluble barium compound (chloride or hydroxide) and a white precipitate forms.
What are the two tests for hydroxide ions?
A pH test
Add ammonium ions and warm it up, creating fumes which turn damp red litmus paper blue.
What is the order you should do anion tests in?
Carbonates, sulphates, halides, ammonium
