Topic 8-Chemical Analysis Flashcards
What is a pure substance?
Something that only contains one element or compund throughout.
How can you test how pure a substance is?
A pure substance will melt or boil at a specific temperature.
You can test the purity of a sample by measuring its melting or boiling point and comparing it with the melting or boiling point of the pure substance.
The closer the measured value is the the actual melting or boiling point the purer your sample is.
Impurities in the sample will lower the melting point and increase the boiling points.
What are formulations?
Useful mixtures with a precise purpose.
What are formulations used for in the pharmeceutical industry?
It makes sure the drug is delivered to the correct part of the body at the right concentration that its consumable and has a long shelf life.
What is the test for chlorine?
Chlorine bleaches damp litmus paper white.
What is the test for oxygen?
If you put a glowing splint inside a test tube containing oxygen the oxygen will relight the glowing splint.
What is the test for carbon dioxide?
Bubbling carbon dioxide through an aqueous solution of calcium hydroxide causes the solution to turn cloudy.
What is the test for hydrogen?
If you hold a burning splint at the open end of a test tube containing hydrogen youll get a squeaky pop.
What does chromatography do?
Separates substances in a mixture.
What is the mobile phase in chromatography?
When the molecules can move. This is always a liquid or gas.
What is the stationary phase in chromatography?
When the molecules cant move. This can be a solid or really thick liquid.
What happens between the mobile and stationary phase during chromatography?
The mobile phase moved through the stationary phase and anything dissolved in the mobile phase moves with it.
How quickly a chemical moves depends how it is distributed between the two phases.
The chemicals that spend more time in the mobile phase than the stationary phase will move further through the stationary phase.
The components in a mixture will separate through the stationary phase so long as the components spend different amount of time in the mobile phase.
The separated components form spots. The number of spots formed may change in different solvents. A pure substance will only ever form one spot in any solvent.
What is the stationary phase in paper chromatography?
The chromatography paper.
What is the moble phase in chromatogrpahy?
The solvent.
What does the amount of time the molecules spend in each phase depend on?
How soluable they are in the solvent.
How attracted they are to the paper.
