8a. Chemical Analysis Flashcards
(20 cards)
What is an element?
A substance that is made up of only one type of atom.
What is a compound?
A substance made up of 2 or more different elements that are chemically bonded together.
What is a pure substance?
A single element or compound that is not mixed with any other substances.
What is a mixture?
2 or more substances that are NOT chemically bonded
What is special about a dpure substances melting and boiling point?
They are both specific and defined.
What is special about an impure substances melting and boiling point?
They are both not specific and undefined.
What is a formulation?
A mixture that has been designed as a useful product or for a specific purpose.
What is the test for hydrogen?
Insert a lit splint, if hydrogen is present a squeaky popping sound will be heard.
What is the test for chlorine?
Insert damp litmus paper and if chlorine is present, the paper will be bleached white.
What is the test for oxygen?
Insert a glowing splint and if oxygen is present, the splint will reignite.
What is the test for carbon dioxide?
Bubble through lime water and if carbon dioxide is present, the lime water will go cloudy.
What does it mean if two substances have the same/ a similar Rf value?
They are most likely the same compound.
What does it mean if the Rf value is different between two substances?
The two substances are definitely not the same compound.
What is the lid for in chromatography?
To stop the solvent from evaporating.
What is the solvent in chromatography also known as?
The mobile phase.
What is the solvent front?
How far the solvent travelled
What is the filter paper also known as in chromatography?
The stationary phase.
Why is the start line in pencil in chromatography?
To prevent error so the start line doesn’t run with the mobile phase.
Why is the solvent below the start line in chromatography?
To prevent error so the substance stays on the filter paper.
How do you calculate the Rf value?
Rf value = distance moved by spot/ distance moved by solvent
