Chemical analysis Flashcards
What is a formulation?
A mixture that has been designed as a useful product. Carefully controlled quantitities of each substance are added to ensure the product has the required properties.
Examples of formulations
Alloys, fertilizers, fuels, medecines, foods, paints and cleaning agents.
What is a sharp melting point?
One specific temperature
What is the diffrence between the melting poins of mixtures and pure substances?
Mixtures melt over a range of temps but pure substances have a sharp melting point.
-Test for hydrogen
-Test for chlorine
-Test for Carbon dioxide
-Test for water vapour
-Test for ammonia
Test for oxygen
-Burns with a squeaky pop
-Bleaches litmus paper
-Turns limewater milky
-Turns anhrydrous copper sulfate from white to blue
-Turns damp red litmus to blue
-Relights a glowing splint
What’s an element
When only one type of atom is present (Sodium)
What’s a mixture
Two or more elements that aren’t chemically combined
What’s a compound
Two or more elements that are chemically combined
What is decanting? Give an example.
Liquid from an insoluble solid. sand + water
What is filtration? Give an example.
Insoluble solid from a liquid. sand + water
What is evaporation? Give an example.
Solute from a solution. Salt from salt solution
What is distillation? Give an example.
Solvent from a solution. Water from salt solution
What is fractional distillation? Give an example.
Mixture of miscible liquids. Petrol + diesel from crude oil.
What is a separating funnel? Give an example.
Mixture of immiscible liquids. Oil and water
What is chromotography? Give an example.
Mixture of soluble solids. Mixture of food dyes.
What are the two phases of chromotography?
The stationary phase the part that doesn’t move and the mobile phase the part that moves.
Explain what to do in paper chromotography
Draw a starting line on the paper in pencil
Small spots of each dye placed on the starting line by a glass capillary tube no more than 5mmm in diameter
Pour 0.1m sodium hydroxide in beaker
Paper left vertically in solvent below level of sample spots
Solvent soaks up paper for a few minutes.
Once solvent near the top take paper out and leave to dry.
Why do substances in a mixture seperate?
Because they have different attractions to the stationary phase and mobile phase.
Whats the formula for each distance the substance moved?
distance travelled by substance
——————————distance moved by solvent
