Chemical Analysis Flashcards
What is true about the melting and boiling points of an impure substance?
They melt and boil at different temperatures than a pure substance and they may melt and boil over a range of temperatures instead of at a single temperature.
Which substance is pure and which is impure?
Top one is impure and lower one is pure.
What is a mixture?
Two or more elements or compounds which are not chemically combined and which are not in fixed proportions.
What are examples of formulations?
Cleaning products
Fertilisers
Foods
Fuels
Medicines
Paints
What is the difference between a formulations and a simple mixture?
In a formulation there are usually many components and the proportion of each component is fixed.
What is a formulation?
A mixture which has been designed as a useful product and each chemical has a useful purpose.
What is pure?
A substance that consists of only one element or only one compound.
What are examples of formulations?
Fuels
Cleaning products
Medicines
Fertilisers
What is chromatography used for?
To separate and identify mixtures of soluble substances.
What is the equation for RF values?
Distance travelled by substance / distance travelled by solvent
Chromatogram
The results of separating mixtures by chromatography
What are the tests for gases for hydrogen, oxygen, carbon dioxide and chlorine?
Hydrogen - gives a squeaky pop with a burning splint
Oxygen - relights a glowing splint
Carbon dioxide - turns limewater cloudy
Chlorine - turns damp blue litmus paper white
What is the mobile phase?
The solvent that moves through the paper, carrying different substances with it.
What is the stationary phase?
Contained on the paper and doesn’t move through it.
