C1 - Atomic Structure And The Periodic Table Flashcards
What is the definition of an element?
A substance where all atoms are the same
What is the definition of a compound?
A substance containing 2 or more elements chemically combined in fixed proportions
What is the definition of a mixture?
Different compounds and elements that are however not chemically combined
If you want to separate a mixture you can use a chemical/ physical seperating technique?
Physical
What are 4 physical methods of seperating a mixture?
Filtration
Crystallisation
Distillation
Chromatography
What is the definition of a molecule?
A molecule is any elements chemically combined
Eg O^2
Filtration is used to separate an insoluble/ soluble solid from a liquid/gas
Insoluble solid
Liquid
What three pieces of equipment are needed to perform filtration?
Conical flask
Filter paper
Filter funnel
Crystallisation is used to separate an insoluble/ soluble solid from a liquid.
Soluble solid
What does the state symbol (aq) mean?
Dissolved in water
How can we make crystallisation happen faster?
Gently heat the solution
What are the 2 main stages of simple distillation?
Evaporation and condensation
What is fractional distillation used for?
To separate a range of different liquids
In fractional distillation the liquids must have different _________ points.
Boiling
When the thermometer temperature is rising steadily in fractional distillation, what does this mean?
There is a mixture of the liquids condensing into the beaker
When the temperature on the thermometer stops rising in fractional distillation what does this mean.
One of the liquids is condensing as a pure substance
What is a solvent?
A liquid that will dissolve substances
What do we call the paper in chromatography?
The __________ phase
Stationary
What do we call the solvent during paper chromatography?
The ______ phase
The mobile phase
Because it moves
In paper chromatography…
A pure/ impure compound will produce a single spot in all solvents.
Pure
True or false
In paper chromatography…
A more soluble substance travels less far along the mobile phase than a substance that is less soluble.
False, a more soluble substance travels further than a substance that is less soluble.
In paper chromatography…
Why do we draw the starting line in pencil and not in pen?
Because the pen ink could dissolve in the solvent and move up the paper
Why did Rutherford use gold in his alpha particle scattering experiment?
Gold can be hammered into very thin few only a few atoms thick
Alpha particles has a negative/positive charge.
Positive