Quantitative Analysis Chapter 1

What is quantitative analysis?

Identifying how much is present

What is qualitative analysis?

Identifying what the unknowns is 

What are the steps of the analytical process?

Question formulation

Procedure selection

Sampling

Sample preparation

Sample analysis

Quality assurance

What is question formulation?

The process of translating a general question into a specific question to be answered through chemical measurements.

What is procedure selection?

The process of searching the chemical literature to find appropriate procedures to, if necessary, devise new procedures to make the measurements.

What is sampling?

The process of collecting a representative sample for analysis 

What is sample preparation?

The process of transforming a sample into a state that is suitable for analysis. This process can include concentrating a dilute analyte and removing or masking interfering species.

What is sample analysis?

The process of measuring the concentration of analyte in several identical aliquots, to assess for variability and guard against gross error in the analysis of a single aliquot  

What is quality assurance?

A practice that demonstrates the reliability of analytical data

What is an Analyte?

the substance being measured or detected

What is a species?

Chemists refer to any element, compound, or iron of interest as a species

What is a quantitative transfer?

Transferring the entire contents from one vessel to another, usually accomplished by rinsing the first vessel several times with fresh liquid and pouring each rinse into th receiving vessel

What is a calibration/standard curve?

A graph showing the value of some property versus the concentration of analytes. When the corresponding property of an unknown is measured, its concentration can be determined from the graph.  

What is average/ mean?

 The sum of all values divided by the number of values

What is standerd deviation?

a statistic that measures how closely data are clustered about the mean value.

What is interference?

A phenomenon in which the presence of one substance changes the signal in the analysis of another substance 

What is masking?

The process of adding a chemical substance (a masking agent) to a sample to prevent one or more components from interfering in a chemical analysis 

What is a lot sample?

The total material form which sample are taken 

What is a bluk/gross sample?

Materials taken from the lot that are being analyzed-usually chosen to be representative of the entire lot 

What is a laboratory sample?

A homogenous mixture of the bulk sample that should have the same composition 

What is an aliquote?

Portions of the laboratory sample used during the experiment for analysis

What is a homogenous mixture?

A mixture having the same composition everywhere.

What is a Random hetergenous mixtures?

It is a material in which there are differences in composition with no pattern or predictability on a fine scale. When you collect portions of the material for analysis, you obtain some of each of the components.  

What is a Composite heterogeneous mixtures?

It is a representative sample prepared from a heterogeneous material. If the material consists of distinct regions, the composite includes each region, with the relative amount proportional to each region's size.