C12 Chemical analysis Flashcards
What is a pure substance?
One that is made up of just one element or compound
What is an impure substance?
A mixture of two or more different elements or compounds
How can you identify if a substance is pure?
If it melt and boils at specific temperatures
How do impurities effect the melting and boiling point of a substance?
Impurities lower the melting point and raise its boiling point
What is a formulation?
A mixture that has been designed to produce a useful product
What are some examples of a formulation? (6)
Fuel, alloys, fertiliser, paint, medicine and cosmetics
What is the mobile phase in paper chromatography?
The solvent
What is the stationary phase in paper chromatography?
The paper
How does the solubility of a substance effect how far it travels in a solvent?
The more soluble the substance is in the solvent, the further up it is carried
How do you find the Rf value?
Rf = distance moved by substance/distance moved by solvent
What two numbers is the Rf always in between?
0 and 1
How do you test for hydrogen?
Hold lighted splint by test tube, if hydrogen is present then a “squeaky pop” sound will occur
How do you test for oxygen gas?
Hold glowing splint by test tube, if oxygen is present then the splint will relight
How do you test for carbon dioxide gas?
Bubble the gas through limewater, if carbon dioxide is present then the limewater turns milky
How do you test for chlorine?
Hold damp blue litmus paper by test tube, if chlorine is present the damp blue litmus paper is bleached and turns white
Flame test: Lithium
Crimson
Flame test: Sodium
Yellow
Flame test: Potassium
Lilac
Flame test: Calcium
Orange-red
Flame test: Copper
Green
Sodium hydroxide solution: Copper
Blue precipitate
Sodium hydroxide solution: Iron II
Green precipitate
Sodium hydroxide solution: Iron III
Brown precipitate
Sodium hydroxide solution: Aluminium
White precipitate
