Testing For Gases Flashcards
Test for chlorine
Chlorine will bleach damp litmus paper and turn it white
If you use blue paper it may turn red for a moment as a solution if chlorine is acidic
Test for oxygen
Glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint
Test for carbon dioxide
Bubbling co2 through (or shaking it) an aqueous solution of calcium hydroxide (lime water) causes solution to go cloudy
Causes limewater to go cloudy
Test for hydrogen
Hold a burning splint at the open end of a test tube containing hydrogen you get a squeaky pop
The pop comes from the hydrogen burning quickly in the oxygen in the air to form water
What is chromatography
An analytical method to separate the substances in a mixture
What are the 2 phases of chromatography
A mobile phase - molecules can move > liquid or gas
A stationary phase - molecules can’t move > solid or really thick liquid
What happens to the 2 phases and substances in chromatography
The substances constantly move between the mobile and stationary phase so an equilibrium is formed between the 2 phases
What does the mobile phase do to the stationary phase
The m phase will move through the s stage and anything dissolved in the m stage move with it
How quickly a substance moves depends on what
How it’s distributed between the 2 phases - if it spends more time in the stationary or mobile stage
What happens if a chemical spends more time in the mobile stage
It will move further through the stationary phase
How many spots will a pure substance make
Only 1 as there is only 1 substance in the sample
What is the stationary phase and mobile phase in chromatography
S phase - the paper (filter)
M phase - solvent ( ethanol/water)
What does the amount of time the molecule spends in each phase depend on
How soluble the solvent is
How attracted they are to the paper
How will molecules be carried up further the paper
If molecules have a high solubility in the Solvent and are less attracted to the paper they will spend more time in the mobile phase
What is the result of chromatography analysis called
A chromatogram
