Chemical Analysis Flashcards
What is a pure substance
A substance made from one single element or compound
How can you tell if a substance is pure
It’s melts at a specific fixed temperature and has a fixed boiling point
What’s the properties of impure substances 
They melt and boil over a range of temperatures
What is a formulation
A complex mixture that has been designed as a useful product
How’s a formulation made
The quantity of each component is carefully measured so that the product has the properties you need
What is paper chromatography used for
To separate substances based on their different solubilities
What is the stationary phase in paper chromatography
The paper because it doesn’t move
What is the mobile phase in paper chromatography
The solvent
How can you tell if a substance is pure in paper chromatography
It will produce a single spot
Why is the starting line drawn in pencil
To prevent anything moving up the solvent
What can the Rf value be used for
To identify a substance
How do you calculate the Rf value
Distance moved by substance / Distance moved by solvent
How do you perform a flame test
Placed a small amount of chemical onto wire mounted in a handle
Place wire into blue flame
The colour of the flame will show which metal ion is present
What colour flame does lithium produce
Crimson flame 
What colour flame does sodium produce
Yellow flame
What colour flame does potassium produce 
Lilac flame
What colour frame does calcium produce
Orange-red flame
What colour frame does copper produce
Green flame 
What’s the disadvantages of using flame tests
- Colour of the flame can be difficult to distinguish
- Samples can contain a mixture of metal ions
How do you carry out flame emission spectroscopy 
A sample of metal is placed in a flame
The light given out is then passed into a spectroscope 
The spectroscope converts the light into a line spectrum
What is flame emission spectroscopy an example of
An industrial method
What are features of industrial methods
Rapid sensitive and accurate
Which three metals form white precipitate in sodium hydroxide
Sodium magnesium and aluminium
Which metal redissolves In excess sodium hydroxide
Aluminium
Copper reacts with sodium hydroxide to form what colour precipitate
A blue precipitate
Iron (Fe 2+) reacts with sodium hydroxide to form what precipitate 
Green precipitate
Iron (Fe 3+) reacts with sodium hydroxide to form what precipitate
A brown precipitate
What is the method for testing for the carbonate ion
Add dilate acid to the sample
The acid will react with the carbonate to form carbon dioxide
Bubble the gas through limewater if it goes cloudy then carbon dioxide is present which proves that the carbonate iron was present
How do you test for the halide ion
Add nitric acid to the sample
Add dilute silver nitrate solution
The halide ions will produce a precipitate
What colour precipitate does Chloride ions form
White
What colour precipitate do bromide ions form
Cream
What colour precipitate do iodide ions produce
Yellow precipitate
How do you test for sulphate ions
Add hydrochloric acid
add barium chloride
if sulphate is present we will see a white precipitate
