CHEMICAL ANALYSIS Flashcards
What is a pure substance?
Something that only contains one element or compound
How do pure substances and melting/boiling points relate?
Pure substances melt or boil at a specific temperature
What happens to the boiling and melting point if a substance is impure?
Decreases melting point
Increases boiling point
What are formulations?
Useful mixtures with a precise purpose
What are examples of formulations?
Medicine
Paint
What is the mobile phase in chromatography?
Where the molecules can move (liquid or gas)
What is the stationary phase in chromatography?
Where the molecules can’t move (solid or really thick liquid)
How do you test for chlorine?
Chlorine bleaches damp litmus paper turning it white (may turn red at first because acidic)
How do you test for oxygen?
Put a GLOWING splint inside a test tube containing oxygen and it will relight
How do you test for carbon dioxide?
Bubbling carbon dioxide through an aqueous solution of calcium hydroxide (limewater) will turn the solution cloudy
How do you test for hydrogen?
Place a LIT splint into a test tube containing hydrogen and a ‘squeaky pop’ sound will be made
How do you test for carbonate ions?
Put substance in test tube and at drops of dilute acid (using pipette)
Connect the test tube to test tube of lime water
If carbonate ions are present, carbon dioxide will be released and turn the limewater cloudy
How do you test for sulphate ions?
Add a couple of drops of dilute hydrochloric acid and then barium chloride solution
If sulphate ions are present, a white precipitate of barium sulphate will form
How do you test for halide ions?
Add a couple of drops of dilute nitric acid and then silver nitrate solution then observe colour of preciptate
What colour precipitate do chloride ions produce?
White (silver chloride)