Elements, Compounds and Mixtures Flashcards
What is an element?
Something that contains only one type of atom
What is a compound?
When two or more elements chemically bond together
What is a mixture?
When various substances are mixed together with no chemical reaction
What is a solvent?
A liquid that’ll allow a solute to dissolve in it
What is a solute?
A chemical that’ll dissolve in a solvent
What is a solution?
A liquid with different chemicals in it
What is a saturated solution?
A liquid that can’t take anymore solute
What is solubility?
The mass of solute dissolved in 100g of solvent
What are the units for solubility?
G/100g
How do you calculate the Rf value for chromatography?
Distance from baseline to spot/distance form baseline to solvent front
How does chromatography work?
It separates the soluble compounds making up the substance and as the solubility determines how far it climbs the chromatogram
What is the mobile phase in chromatography?
The movement of the solvent taking the dyes/inks upwards
What is the stationary phase in chromatography?
The chromatography paper
What is a pure substance?
Something made up of only one type of molecule
How does a pure substance melt?
It melts at a specific temperature
What is an impure substance?
Something made up of different substances
How does an impure substance melt?
It melts over a range of temperatures
What is filtration used for?
When a solid isn’t dissolved in a liquid
What is crystallisation used for?
A solid dissolved in liquid
What is simple distillation used for?
A solution made up of two substances with different boiling points
What is fractional distillation used for?
Misable liquids
What is chromatography used for?
Lots of solutes dissolved in a solution
What extra things might you do if ethanol is the solvent and why on a chromatogram?
Put a lid over the chromatogram in order to stop stuff from evaporating
