Volumetric Analysis Flashcards
(37 cards)
Explain volumetric analysis
Involves dissolving a weighed amount of sample and titrating the resulting solution with a standard solution.
Involve measuring the volume of a solution of known concentration that is needed to react completely with the analyte.
Volumetric titration
It is the progressive addition of standard solution to a solution with which it reacts.
Titration
It is a solution with known concentration.
Standard solution
It is a process of determining the concentration of a standard solution.
Standardization
A pure dry solid substance of known chemical composition used in the direct titration.
Primary standard
What are the requirements for volumetric analysis?
- Accurate balance with which to weigh materials for analysis
- Graduated instrument to measure volumes of solutions used
- Standard solutions
- Indicators
It is used for measuring accurate and precise volumes of solutions.
Pipette
Used for pouring measured volumes of solutions
Burette
Give an example of graduated instrument to measure volumes of solutions used.
*Conical flask
*Wash bottles
*Funnel
*Volumetric flask
This contain distilled water for cleaning equipment
Wash bottles
It is used for mixing two solutions
Conical flask
For transfer of liquids without spilling
Funnel
It is used to make up accurate volumes for solutions of known concentration
Volumetric flask
What are the steps in titration
1.) The burette is attached to a clamp stand above a conical flask
2.) The burette is filled with one of the solutions
3.) A pipette is used to measure an alliquot of the other solution into the conical flask
4.) Prepare a number of flask for repeat tests
5.) Last an indicator is added to the conical flask
It is by dissolving a weighd amount of pure dry chemical and diluting the solution to an exactly measured volume
Direct titration
Titration of a weighd portion of pure dry chemical by the solution to be standardized
Primary standard
Titration of a measured volume of a solution that has itself been standardized previously
Secondary standard
What are the characteristics must be present in a primary standard
It must be a substance with known purity and definite composition
It must be stable at the temperature for drying
Its composition must not be affected by changes in humidity
It must react quantitatively and in a known way the solution to be standardized
There must be a suitable indicator for the titration
Properties of an ideal standard solution
It’s concentration should remain constant for a long time to eliminate the need for the restandardization.
Its reaction with the analyze should be rapid
Its reaction with the analyte should be nearly complete
Its reaction with the analyte could be described by a balanced equation
A method should exist for detecting the equivalence point of titration
The standard solution is titrated directly with the sample in question
Direct Titration or dead stop
An excess reagent is added to the sample in question and the excess reagent is titrated with another standard solution
Indirect titration
The analyte displaces a species usually from a complex and the amount of the displaced species is determined by a titration
Displacement titration
It is added to the system
Internal indicators
