Chemical Analysis Flashcards
How do you know if a substance is pure?
It has a specific melting and boiling point
How can you measure if something is pure?
By measuring its boiling and melting points and comparing it to a pure substances boiling and melting point
The closer to the specific melting and boiling point the purer the substance
What will impurities have?
Lower melting point- increase the melting range
Higher boiling point
What are formulations?
Useful mixtures with exact amount of components for a precise purpose
Why are formulations important in the pharmaceutical industry?
Altering the formulation of a pill can deliver the drug to the correct part of the body at the right concentration
What is the test for chlorine?
Bleaches damp litmus paper white
If you use blue litmus paper it will go red (acidic)
What is the test for oxygen?
Glowing splint in a test tube, splint will relight
What is the test for hydrogen?
Burning splint at the open end of a test tube, a squeaky pop noise will be made
What is the test for carbon dioxide?
Bubble CO2 through limewater (calcium hydroxide), turns cloudy
How do you work out the Rf value?
Distance of spot / distance of solvent
What is a mobile phase?
When the molecules can move (liquid or gas)
What is a stationary phase?
When the molecules can’t move (solid or thick liquid)
What effects the amount of time the molecules spend in each phase?
How soluble they are in the solvent
How attracted they are to the paper
What will molecules with a higher solubility do?
Spend more time in the mobile phase as they are less attracted to the paper
What is the Rf value dependant on?
The solvent you use if you change the solvent the Rf value will change