Ch1: Experimental Chemistry Flashcards
A mixture is made up of…
Two or more substances that are not chemically combined
Air’s density
32
O2 –> (Mr (16) x (2))
To separate a mixture of two solids, we use a solvent in which one solid is _______ (The other is _______ in that ______)
soluble and insoluble in that solvent
substances can turn straight into a gas on heating, without becoming a liquid first
what is this called?
sublimation
A pure substance is made up of…
One single element or compound. It is not mixed with any other substance.
A mixture is made up of..
Two or more substances that are not chemically combined together
Some substances can turn straight into gas on heating, without becoming a liquid first. This is called….
Sublimation
Sublimation is used to separate a solid that….. from one that does not.
Sublimes.
Sublimation can he used to separate____ mixtures such as….
Solid-solid, ammonium chloride and sodium chloride.
Sublimation test:
A mixture is placed in an evaporating dish with an inverted funnel on the top. It is then gently _____.
The ammonium chloride _____ and changed directly to a _____ which _____ back to a ______on the cold glass funnel.
What remains in the evaporating dish?
Heated
Sublimes, gas, cools
Sodium chloride
A mixture made of solid particles of different sied can be separated by….
Sieving
…….. can be used to separate a magnetic substance from a non-magnetic substance.
Magnetic attraction
Meaning of the term ‘solute’
E.g. …..
Substance that dissolves ______.
The liquid that the substance dissolves in
Solvent
Characteristics of solutions
Clear. Some may be coloured (e.g. brown, blue, green) or have no colour (colourless)
Filtration is used to separate an…… from a liquid. a funnel lined with filter paper is usually used.
Insoluble solid
……. is used to separate a soluble solid from a liquid.
Evaporation
……. is a process of obtaining a soluble solid from a solution by heating the solution until all the water has boiled off
Evaporation to dryness
Process of evaporation to dryness
Obtaining a soluble solid from a solution by heating the solution until all the water has boiled off
If we heat the solution so that only some of the solvent vaporises, and then leave the hot saturated solution to cool, some of the solid reappears as pure …….
this is called……
Crystals, crystalization
Simple distillation is used to separate the …….(liquid) from a solution
Solute
Boiling chips are added to
Ensure smooth boiling
As the solution boils, vapour rises. If distillation is allowed to carry on, ……
a solid residue of the salt will be left in the flask
The condensed water in simple distillation in the conical flask is called the….
Distillate
The separating funnel is used to….
Separate two liquids which do not mix together
Mixtures that do not mix together are…
Immiscible
In the separating funnel, when the tap is opened, what drained?
The densest layer is allowed to drain into the beaker.
Process of separating a mixture of miscible liquids which dissolve in ……
Chromatography, same solvent
Process of separating dyes in food colouring, ink or pigments
Paper chromatography to a chromatogram
Some solutes are less soluble in the solvent and thus does not travel very far across the paper. What does this show?
Difference in solubility allowing the dyes in the food colouring to be separated
Process of separating a mixture of miscible liquids with different boiling points.
Fractional distillation
In fractional distillation, explain what is happening in the fractionating column
The liquid with the lower boiling point passes into the condenser. Higher boiling point condenses and falls back into the flask.
What does presence of impurities do to the melting points?
Increases the melting points, causing the substance to melt over a range of temperatures.
Suitable drying agent for carbon dioxide
Fused calcium chloride.
Suitable drying agent for Ammonia
Quicklime (calcium oxide)
Suitable drying agent for Hydrogen
Fused calcium chloride
Fused calcium chloride. It readily absorbs moisture from the air, So it must be…
Freshly heated before use
Quicklime (calcium oxide) absorbs moisture and carbon dioxide from the air, so it must be…
Freshly heated before use
