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Concentration and Solutions, - Coggle Diagram
Concentration and Solutions
Solvent
Solute
Solvent + Solute = solution
Standard solutions
Primary Standard Solution
Low Reactivity
High Molar Mass
Does not change composition in contact with air
High Purity (99.9%)
Solution that is made of a primary substance with the following:
Secondary Standard Solution
Solution that has been standardised against a primary standard solution
Important for volumetric analysis- uses technique of titration
Titration: concentration of a solution is determined by reacting it with a standard solution (with known concentration)
Serial Dilution
Diluting a stock solution multiple times
For example, if 10.0 cm3 of a 1.00 mol dm-3 solution is made up to 100 cm3 (with 90.0 cm3 of distilled water), the concentration will decrease to 0.100 mol dm-3.
Volumetric Analysis
Titration
Burette is filled with standard solution of known concentration (Titrant)
A carefully measured volume of the solution with the unknown concentration (the analyte) is placed in a conical flask below the burette
An indicator is used to determine the end-point of the titration.
Acid- Base: A suitable indicator is added to the solution so that the end point can be easily identified.
Back Titration:
Technique for analysing impure substances
Titration in reverse
an excess of titrant is added to the analyte and the excess titrant is then titrated to determine how much excess titrant remains
Used when one reactant is insoluble in water but does react with acid
Example: Calcium Carbonate