Chemical Analysis Flashcards
What does pure mean?
A substance that only contains one type of element or compound
Pure substances do what over a range of temperatures?
Change state
What is the name of the one temperature that pure substances melt and solidify at?
Melting point
What is the name of the one temperature that pure substances boil and condense at?
Boiling point
What is a formulation?
Mixtures that have been designed to have specific properties
What happens during chromatography?
Mixtures separate into their components
Why do the components separate during chromatography?
They move a different distance depending on its attraction for the paper and solvent
What can chromatography be used for?
To identify artificial colours (in food) by comparing it with results from known substances
Equation for Rf value
Distance moved by substance/distance moved by solvent
What is the Rf value used for in chromatography?
To identify the component
What are the properties of hydrogen?
Colourless, combines violently with oxygen when ignighted
What is the test for hydrogen?
Lit splint and burns with squeaky pop
What are the properties of chlorine?
A green, poisonous gas that bleaches dyes
What is the test for chlorine?
Turns damp red litmus paper white
What are the properties of oxygen?
A colourless gas that helps fuels burn more readily than in air
What is the test for oxygen?
Relights a glowing splint
What are the properties of carbon dioxide?
Colourless gas
What is the test for carbon dioxide?
Turns limewater cloudy when bubbled through it
What are instrumental methods?
Standard lab equipment is used to detect and identify substances