Topic 3 Flashcards
compound
A substance made of two or more elements chemically bonded together
Mixture
Two or more chemical substances found together but not chemically bonded.
element
A chemical substance that cannot be broken down into simpler substances. It is composed as one type of atom only.
anhydrous
Salts that do not contain water of crystallisation often resulting from hydrated salts being heated.
hydrocarbon
A compound made of hydrogen and carbon only.
petroleum
The mixture of hydrocarbons found naturally formed by the decay of marine organisms. Also known as crude oil.
Solvent
A liquid substance within which a solid can dissolve.
solute
A soluble solid that has dissolved in a solvent.
residue
The solution that passes through the filter in filtration.
filtrate
The solution which passes through the filter during filtration.
chromatography
A method used to separate and identify substances by dissolving them in a solvent and allowing them to be carried by the solvent through a sheet of filter paper. The dissolved solutes are deposited along the sheet of paper according to their solubility and mass.
soluble
able to be dissolved
Locating agent
A chemical substance that will react with the solute(s) separated in chromatography to produce a coloured substance. Locating agents are used to identify colourless compounds separated by chromatography.
Rf equation
Rf=distance travelled by substance
———————————————-
distance travelled by solvent
Fractional distillation
A chemical process that describes heating and separating substances by distillation into more useful products (or fractions) based on their boiling points. It is used in the refining of crude oil.
filteration
A purification method used to remove an insoluble solid from liquids by pouring through a filter, such as filter paper.
crystallisation
A purification method used to obtain solid dissolved in a solution. As the liquid part of the solution cools and becomes denser, there is less space for the solid particles to occupy. These particles are excluded from the liquid and form crystal arrangements on the side of the vessel containing them.
Distillation
A purification method used to separate a mixture of liquids by boiling and condensing.
simple distillation
used to obtain a solvent from a solution
Carbonate test
Test - Add dilute acid
Result - carbon dioxide produced
Chloride test
Test - acidify with dilute nitric acid, then add aqueous silver nitrate.
Result - white ppt (ppt - precipitate)
Bromide test
Test - acidify with dilute nitric acid, then add aqueous silver nitrate.
Result - Cream ppt
Iodide test
Test - acidify with dilute nitric acid, then add aqueous silver nitrate.
Result - yellow ppt
Nitrate test
Test - Add aqueous sodium hydroxide then aluminium foil; warm carefully.
Result - Ammonia produced. turns damp red litmus paper blue.
Sulfate test
Test - Acidify, then add aqueous barium nitrate or barium chloride.
Result - white ppt.
sulfite test
Test - Add dilute hyrdochloric acid, warm gently and test for the presence of sulfur dioxide.
Result - Sulfur dioxide produced will turn acidified aqueous potassium manganate (VII) from purple to colourless.
aluminium(Al3+)
Effect of aqueous sodium hydroxide - white precipitate, soluble in excess – gives a colourless solution
Ionic equation - Al3+(aq)+3OH−(aq)→Al(OH)3(s)
ammonium(NH4+)
Effect of aqueous sodium hydroxide - ammonia gas produced on heating. Turn red litmus blue.
Ionic equation - NH4+(aq)+OH−(aq)→NH4OH(aq)
NH4OH(aq)→NH3(g)+H2O(l)
calcium(Ca2+)
Effect of aqueous sodium hydroxide - white precipitate, insoluble in excess
Ionic equation - Ca2+(aq)+2OH−(aq)→Ca(OH)2(s)
chromium(III)(Cr3+)
Effect of aqueous sodium hydroxide - green precipitate, soluble in excess – gives a green solution
Ionic equation - Cr3+(aq)+3OH−(aq)→Cr(OH)3(s)
copper(II)(Cu2+)
Effect of aqueous sodium hydroxide - light blue precipitate, insoluble in excess
Ionic equation - Cu2+(aq)+2OH−(aq)→Cu(OH)2(s)
iron(II)(Fe2+)
Effect of aqueous sodium hydroxide - green precipitate, insoluble in excess
Ionic equation - Fe3+(aq)+3OH−(aq)→Fe(OH)3(s)
zinc(II)(Zn2+)
Effect of aqueous sodium hydroxide - white precipitate, soluble in excess – gives a colourless solution
Ionic equation - Zn2+(aq)+2OH−(aq)→Zn(OH)2(s)
Ammonia gas test
Damp red litmus paper turns blue.
Carbon dioxide gas test
Limewater turns milky
Chlorine gas test
damp litmus paper bleaches white
Hydrogen gas test
lighted splint ignites gas with a ‘pop’ sound
Oxygen gas test
Glowing splint relights
Sulfur dioxide
Turns acidified aqueous potassium manganate (VII) from purple to colourless.
lithium, Li+
flame colour - red
sodium, Na+
flame colour - yellow
potassium, K+
flame colour - lilac
copper(II), Cu2+
flame colour - blue-green
barium, Ba2+
flame colour - green
calcium, Ca2+
flame colour - orange-red
