1b - elements compounds and mixtures Flashcards
what is centrifuging
a method for separating out particles of different densities in a substance.
What is an atom?
An atom is the smallest particle of a chemical element.
What is an element?
An element is something made up of one type of atom.
what are the two groups elements can be?
Metals and non-metals
What is a compound?
Two or more elements that are chemically combined and can
be shown by formulae
Do compounds have the same properties as the elements they are made of?
No
What is a mixture?
two or more elements or compounds that aren’t chemically
combined.
What are the 5 methods that mixtures can be separated with?
- Filtration,
- evaporation or crystallisation
- simple distillation
- fractional
distillation - chromatography
what is simple
distillation?
Simple distillation is used to separate liquid from a solution
what is evaporation?
Evaporation is a technique for separating a solid dissolved in a solvent from the solvent
what is crystallisation?
removing some of the solvent by evaporation to form a saturated solution
what is fractional distillation?
Fractional distillation is a technique for separating a mixture of liquids with the same boiling point
what is filtration?
Filtration is used to separate an insoluble solid in a liquid. The insoluble solid gets caught in the filter paper, because the particles are too big to fit through the holes in the paper.
what is chromatography?
Chromatography is used to separate a mixture of substances dissolved in a solvent.
How do you calculate the Rf value?
Distance moved by the spot / distance moved by solvent
What is a separating funnel?
A separating funnel is used for separating immiscible liquids.
what does insoluble mean?
a substance that won’t dissolve in a solvent.
what is the difference between a compound and a mixture?
a compound is two or more chemically combined elements, but a mixture is two or more substances that aren’t chemically combined.
how does simple distillation work?
the liquid boils off and condenses in the condenser
how does filtration work?
The insoluble solid gets caught in the filter paper, because the particles are too big to fit through the holes in the paper.
what is a solute?
a substance that is dissolved in a solvent.
what does miscible mean?
substances that mix together in all
proportions
what does soluble mean?
a substance that can be dissolved in a solvent
