chemistry flashcards unit 1

definition of an atom
smallest part of an element - cannot be chemically split into smaller parts
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definition of an element
substance made fron only ONE type of atom, listed in the periodic table
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definition of a compound
a substance made from two or more atoms or elements CHEMICALLY joined
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name the four signs of a chemical reaction in order of significance
new product formed, heat energy change, effervescence, colour change.
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definition of a mixture
two or more elements or compounds not chemically joined
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6 steps in the scientific model
scientists come up with idea, experimental data tested against the idea, publish their idea and results to other scientists, other scientists test the experiments anad modify the idea, publish the repeats of the results, consensus formed
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name souces of scientific publication
scientific journal, confrences, scientific websites,
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diatomic elements
I Br-ing Cl-ay F-or O-ur N-ew H-ouse
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why are mixtures easy to seperate
you can seperate them without a chemical reaction by exploiting the physical differences between the 'components'
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name the five methods for seperating mixtures
filtration, distillation, fractional distillation, crystalisation, chromotography
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what is filtration used to seperate
insoluble solid from a liquid
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what is distillation used to seperate
a solvent from a solution
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what is fractional distillation used to seperate
two liquids with different boiling points
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what is crystalisation used to seperate
a soluble solid from a liquid
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what is chromotography used to seperate
complex mixtures
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examples of each of the types of mixture sperated in the five ways
sand and water - filtration; salt and water - crystalisation; ethanol and water - distillation; crude oil - fractional distillation; salivia - chromotography
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how to produce a pure dry insoluble solid from filtration
using filter paper filter the solution and collect the wet precipitate, wash with clean solvent to remove any soluble impurities then air or low temperature oven dry
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how does simple distillation seperate a solvent from a solution
heat the solution in a distiallation flask - the liquid will boil vapour rises into the condenser liquid condensed and collected if water 100degreesC
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how does fractional distillation sperate liquids with different boiling points
mix of liquids is heated, vapours rise up fractionating column and fall back down when the tempertature ther is < their bp until the temp at the top is their bp then this liquid with the lowest bp is condensed,collected other ls collected dif stages
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how crystalisation gets a pure dry soluble solid from solution
dissolve sample in water heat solution until most of the water is evaporated off and small crystals begin to form, hot filter to remove insoluble impurities, cool at room temp, cold filter to remove soluble impurities wash with cold solvent air dry
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how chromotography seperates complex mixtures*
2 phases, the stationary phase mobile phase when a solvent is added The different dissolved substances in a mixture are attracted to the two phases in different proportions. This causes them to move at different rates through the paper in this case.
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Other cards in this set

Card 2

Front

substance made fron only ONE type of atom, listed in the periodic table

Back

definition of an element

Card 3

Front

a substance made from two or more atoms or elements CHEMICALLY joined

Back

Preview of the back of card 3

Card 4

Front

new product formed, heat energy change, effervescence, colour change.

Back

Preview of the back of card 4

Card 5

Front

two or more elements or compounds not chemically joined

Back

Preview of the back of card 5
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