Chemical Tests Flashcards
What is the chemical test for Oxygen?
Re-lights a GLOWING splint
What is the chemical test for Hydrogen?
A BURNING splint “pops”
What is the chemical test for Carbon Dioxide?
Turns limewater milky
What is the chemical test for Nitrogen?
Very unreactive. Do all the other tests and if there is no reaction, then the gas is Nitrogen.
Alkanes are what?
Saturated
Alkenes are what?
Unsaturated (contain C=C)
What is the chemical test for unsaturation?
Add BROMINE SOLUTION to an unknown hydrocarbon. If the bromine solution DECOLOURISES the hydrocarbon is UNSATURATED, if the bromine solution remains UNCHANGED, the hydrocarbon is SATURATED.
What is the test for reducing sugars?
Place the sugar in a boiling tube with some BENEDICT’S SOLUTION and put it into a beaker of boiling water. The sugar is a reducing sugar if the colour change BLUE—>GREEN—>BRICK RED is seen.
What is the test for starch?
Add iodine. If the colour change BROWN—>BLUE/BLACK is observed in the iodine, starch is present.
What is the colour change for an aldehyde in acidified potassium dichromate solution?
Orange—>Blue/Green
What is the colour change for an aldehyde in Fehling’s solution?
Blue—>Brick Red
What is the colour change for an aldehyde in Tollen’s reagent?
Colourless—>Sliver mirror
What is the colour change for an aldehyde in Copper(II) Oxide?
Black—>Brown
