Chemical Analysis Flashcards
What’s a pure substance
Single element or compound have one melting or boiling point
What’s an impure substance
A mixture doesn’t have one boiling and melting point
What’s a formulation
A mixture designed for a specific purpose (components carefully controlled)
What are the two phases of chromatography
Mobile (liquid or gas carried) and stationary phase (solid or viscous liquid)
What happens if a substance is attracted to the mobile or stationary phase?
Mobile: moves far
Stationary: doesn’t move far
In paper chromatography what is the stationary and mobile phases?
Mobile phase: solvent
Stationary: paper
How to calculate Rf value
Tf = distance of substance/distance travelled by solvent
What’s the gas test for hydrogen
Squeaky pop (when put a lit splint into test tube)
What’s the gas test for chlorine
Turns damp litmus paper white
The gas test for oxygen
Delights flowing splint
Gas test for carbon dioxide
Turns limewater cloudy
Give two advantages for modern instrumental methods
More accurate and faster
Name a instrumental method using highly accurate equipment
Flame emission spectroscopy
What colour does copper go (flame test)
Green
What colour does calcium go (flame tests)
Brick red
What colour does potassium go (flame tests)
Lilac
What colour does lithium go (flame tests)
Crimson red
What colour does sodium go (flame tests)
Yellow
Describe method of flame test
1 - heat metal loop over flame and dip in HCl
2-dip into compound
3- put in flame and observe colour
What happens if a compound contains a mixture of ions
Some colours of ions are masked
What’s produced when react a calcium carbonate and HCl together
A salt, CO2 and water
What’s formula for precipitate
Metal ion + sodium hydroxide ——> precipitate
What precipitate colours for aluminium and calcium
Aluminium - white (dissolves when more is added)
Calcium - white
What colour pracipitate is formed for magnesium and copper
Magnesium - white
Copper - blue
What colour pracipitate is formed for iron (II) and iron (III)
Iron (II) - green
Iron (III) - brown
What’s added to a halide ion to produce a silver halide pracipitate
Silver nitrate
What colour silver halide precipitate is former for silver chloride, bromide and iodide
Chloride - white
Bromide - cream
Iodide - yellow
