Lesson 2 Flashcards
General steps for chemical analysis that answers the question “what information is needed”
Identify the problem
Step that answers the question “what material is required for analysis
Select the sample
Step that answers “how the sample prepared”
Prepare the sample
Step that answers “how desired the data obtained”
Conduct the analysis
What are the general steps for chemical analysis
- Identify the problem
- Select the sample
- Prepare the sample
- Conduct the analysis
- Analyze the data
Determines the presence or absence of a particular compound, but not the mass or concentration
Qualitative analysis
Test to detect starch
Iodine test
Qualitative chemical or metallurgical assay which uses acid
Acid test
Test that detect carbohydrates
Molisch test
Test for detecting the presence of amino acids
Ninhydrin test
Test for detecting the presence of peptide bonds
Biuret test
Test to detect iodine
Starch test
A presumptive blood test in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin
Kastle meyer test
Measurement of the quantities of particular chemical constituents present in a substance
Quantitative analysis
A chemical substance is measured by determining the volume or amount of a well defined reagent that is needed to react with this analyte
eg. Acid base titrate
Volumetric analysis/ titration
Involves determining the amount of material present by weighing the sample beyand or after some transformation
Gravimetric analysis
An analytical procedure usued to detect the presence of certain elements, primarily metal ions, based on each elements characteristics emission spectrum.
Flame test
the principle behind volumetric analysis is that the mass of an ion in a pure compound can be determined and then used to find the mass percent of the same ion in a known quantity of an impure compound. True or false?
False, it should be gravimetric analysis
Common steps followed in gravimetric analysis
- Preparation of a solution containing a known weight of the sample
- Separation of the desired constituent
- Weighing the isolated constituent
- Computation of the amount of the particular constituent in the sample from the observed weight of the isolated substance.
A feild of analytical chemistry that investigates analytes using scientific instruments.
Instrumental methods
Measures the interaction of the molecules with electromagnetic radiation
Spectroscopy
Measures mass to charge ratio of molecules using electric and magnetic fields
Mass spectrometry
What are the sequence of observation in mass spectrometry?
- Ionization
- Acceleration
- Deflection
- Detection
•Makes use of the production or consumption of electrons by chemicals
•measure the potential (volts) and or current(amps) in an electrochemical cell containing the analyte
Electrochemical analysis
4 categories of electrochemical analysis
- Potentiometry
- Coulometry
- Amperometry
- Voltammetry
Category of electrochemical analysis that transferred charge is measure over time
Coulometry
Category of electrochemical analysis that the difference in electrode potentials is measured
Potentiometry
Category of electrochemical analysis that the cell’s current is measured over time
Amperometry
Category of electrochemical analysis that the cell’s current is measured while actively altering the cell’s potential
Voltammetry
The properties of materials are studied as they change with temperature
Thermal analysis
Process of measuring the amount of heat released or absorbed during a chemical reaction
Calorimetry
An analytical technique used to determine a materials thermal stability and it’s fraction of volatile components by monitoring the weight change that occurs as a sample is hrated at a constant rate.
Thermogravimetric analysis (TGA)
An approach used to remove one type of chemical from another.
Separation method
Separation of mixture
Chromatography
Is a method used to separate charged particles from one another
Electrophoresis
General categories of analytical techniques
•classical methods
•instrumental methods
