Chemistry Topic 8 Flashcards
What is a pure substance
Something that contains one compound or element only
How to know if a substance is pure
It will melt or boil at specific temperature
What are formulations
Useful mixtures with exact amounts of components
Where can formulations be found
Cleaning products
What is chromatography used for
To separate substances in mixtures
What is the mobile and stationary phase in chromatography
Mobile phase- where molecules can Move: solvent
Stationary: don’t move : paper
What is the Rf value
Distance travelled by substance:distance from baseline to centre of spot
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Distance travelled by solvent
Why is the test for chlorine gas and what are the results
Chlorine bleached damp litmus paper- turns white
Test for oxygen gas and result
Put glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint
Test for carbon dioxide and results
Bubble carbon dioxide through lime water it will turn cloudy
Test for hydrogen and result
Hold a lit splint at open end of test tube containing hydrogen, it will have a squeaky pop
How can y test for carbonate
Put a sample in test tube then add drops of dilute acid. Then connect the test tube to limewater. It will turn cloudy when it bubbles
How to test for sulfates
Add drops of dilute hydrochloride acid and barium chloride. If sulfate ions are present, a white precipitate is formed.
How to test for halides and results
Add drops of dilute nitric acid and silver nitrate solution.
Chloride: white
Bromide: cream
iodide: yellow
What will be formed for the test for chloride
White precipitate
