Question 1

____________________ dissolves substances that will not dissolve in acid in a hot,molten inorganic____________________.

Accepted Answer

A) Smelting;solvent 
B) Fusion;flux 
C) Smelting;flux 
D) Fusion;solvent 
E) None of these choices is correct. 
A) Smelting;solvent 
B) Fusion;flux 
C) Smelting;flux 
D) Fusion;solvent 
E) None of these choices is correct. B

Question 2

All of the following are used to grind solids into a fine powder,except:

Accepted Answer

A) mortar and pestle. 
B) Wig-L-Bug 
C) Shatterbox laboratory mill. 
D) ball mill. 
E) vortexer. 
A) mortar and pestle. 
B) Wig-L-Bug 
C) Shatterbox laboratory mill. 
D) ball mill. 
E) vortexer. E

Question 3

How many replicates must be completed for sampling deviation of 3.5% to achieve a 1% standard deviation?

Accepted Answer

50

Question 4

Which of the following is INCORRECT for decomposition of organic substances?

Accepted Answer

A) Microwave-induced combustion is a form of dry ashing. 
B) An example of wet ashing is microwave digestion with acid in a Teflon bomb. 
C) Wet ashing with perchloric aicd is an extremely hazardous procedure and is best avoided. 
D) Kjeldahl digestion digests organic material with sulfuric acid for nitrogen analysis. 
E) The Carius method of wet ashing is performed with fuming H2SO4 in a sealed,heavy-walled glass tube at 200 oC to 300 oC. 
A) Microwave-induced combustion is a form of dry ashing. 
B) An example of wet ashing is microwave digestion with acid in a Teflon bomb. 
C) Wet ashing with perchloric aicd is an extremely hazardous procedure and is best avoided. 
D) Kjeldahl digestion digests organic material with sulfuric acid for nitrogen analysis. 
E) The Carius method of wet ashing is performed with fuming H2SO4 in a sealed,heavy-walled glass tube at 200 oC to 300 oC.

Question 5

____________________ is the procedure in which analyte is chemically modified to make the compound easier to detect or separate.

Accepted Answer

A) Labeling 
B) Derivatization 
C) Tagging 
D) Marking 
E) Modification 
A) Labeling 
B) Derivatization 
C) Tagging 
D) Marking 
E) Modification

Question 6

A mixture contains 5% NaCl particles and 95% NaBr particles.If 103 particles are taken,what is the relative standard deviation for NaCl and NaBr?

Accepted Answer

A) 13.78% for NaCl 0.73% for NaBr 
B) 186.2% for NaCl 9.80% for NaBr 
C) 95.00% for NaCl 5.00% for NaBr 
D) 54.39% for NaCl 2.86% for NaBr 
E) 6)89% for NaCl 0.36% for NaBr 
A) 13.78% for NaCl 0.73% for NaBr 
B) 186.2% for NaCl 9.80% for NaBr 
C) 95.00% for NaCl 5.00% for NaBr 
D) 54.39% for NaCl 2.86% for NaBr 
E) 6)89% for NaCl 0.36% for NaBr

Question 7

Which of the following are NOT liquid extraction techniques?
I emulsive liquid-liquid microextraction
II dispersive liquid-liquid microextraction
III solid-supported liquid-liquid extraction
IV supercritical fluid extraction
V solid-liquid microextraction

Accepted Answer

A) I and II 
B) III and V 
C) I and IV 
D) IV only 
E) I and III 
A) I and II 
B) III and V 
C) I and IV 
D) IV only 
E) I and III

Question 8

All of the following are true for dissolving inorganic materials in acid,except:

Accepted Answer

A) metals with positive reduction potentials should dissolve in nonoxidizing acids such as HCl,HBr,HF,H3PO4,etc. 
B) volatile species formed by protonation of anions such as carbonate will be lost from hot acids in open vessels. 
C) volatile metal halides such as SnCl4 and some metal oxides can be lost from hot acids in open vessels. 
D) hot hydrofluoric acid dissolves silicates. 
E) substances that do not dissolve in nonoxidizing acids may dissolve in oxidizing acids such as HNO3,hot concentrated H2SO4,or hot concentrated HClO4. 
A) metals with positive reduction potentials should dissolve in nonoxidizing acids such as HCl,HBr,HF,H3PO4,etc. 
B) volatile species formed by protonation of anions such as carbonate will be lost from hot acids in open vessels. 
C) volatile metal halides such as SnCl4 and some metal oxides can be lost from hot acids in open vessels. 
D) hot hydrofluoric acid dissolves silicates. 
E) substances that do not dissolve in nonoxidizing acids may dissolve in oxidizing acids such as HNO3,hot concentrated H2SO4,or hot concentrated HClO4.

Question 9

Sample storage is an important aspect of sample preparation.Which is NOT true for sample storage?

Accepted Answer

A) Glass should not be used with trace analysis of ions and proteins in solution. 
B) Analytes may react with the container. 
C) A stored sample may change with time. 
D) New plastic containers do not require washing before use. 
E) A stored sample may react with air. 
A) Glass should not be used with trace analysis of ions and proteins in solution. 
B) Analytes may react with the container. 
C) A stored sample may change with time. 
D) New plastic containers do not require washing before use. 
E) A stored sample may react with air.

Question 10

What mass of a solid sample containing 2.5% analyte particles and 97.5% solvent particles must be taken to give a standard deviation of 2% of the number of analyte particles,if the average particle volume is 2.54 nL and the sample has an average density of 1.548 g/mL?

Accepted Answer

The answer of What mass of a solid sample containing...

Question 11

What mass will give a sampling standard deviation of 3.5% for a sampling constant of 40.9?

Accepted Answer

The answer of What mass will give a sampling standard...

Question 12

A mixture contains 2.5% KBr and 97.5% inert particles.What is the relative standard deviation for KBr is 50 000 particles are taken?

Accepted Answer

The answer of A mixture contains 2.5% KBr and 97.5%...

Question 13

Calculate the overall standard deviation if the analytical standard deviation is 6% and the sampling standard deviation is 4%.

Accepted Answer

The answer of Calculate the overall standard deviation if the...

Question 14

To calculate the number of required replicates for analysis the equation   is used.Which statement is NOT true for the equation and calculation?

Accepted Answer

A) t = the Student's t value for n − 1. 
B) ss is the sampling standard deviation. 
C) e is the difference between the sampling standard deviation and the desired sampling standard deviation. 
D) The initial calculation assumes an infinite n value and the according Student's t value. 
E) The n value from a calculation dictates the Student's t value used in the next calculation. 
A) t = the Student's t value for n − 1. 
B) ss is the sampling standard deviation. 
C) e is the difference between the sampling standard deviation and the desired sampling standard deviation. 
D) The initial calculation assumes an infinite n value and the according Student's t value. 
E) The n value from a calculation dictates the Student's t value used in the next calculation.

Question 15

Sample preparation of a laboratory sample can involve all of the following,except:

Accepted Answer

A) laboratory samples that do not dissolve under mild conditions may require acid digestion or fusion. 
B) organic material may be destroyed by combustion or wet ashing. 
C) solids are typically dried at 110 oC at atmospheric pressure to remove absorbed water prior to analysis. 
D) a portion of a course solid laboratory sample should be ground into a fine powder for analysis. 
E) temperature-sensitive samples may be stored in an environment to achieve a constant,reproducible moisture level. 
A) laboratory samples that do not dissolve under mild conditions may require acid digestion or fusion. 
B) organic material may be destroyed by combustion or wet ashing. 
C) solids are typically dried at 110 oC at atmospheric pressure to remove absorbed water prior to analysis. 
D) a portion of a course solid laboratory sample should be ground into a fine powder for analysis. 
E) temperature-sensitive samples may be stored in an environment to achieve a constant,reproducible moisture level.

Question 16

A 4.17 g sample has a 4% sampling standard deviation.What mass sample must be taken to decrease the sampling standard deviation to 2%?

Accepted Answer

A) 8)34 g 
B) 16.68 g 
C) 10.43 g 
D) 4)17 g 
E) 15.64 g 
A) 8)34 g 
B) 16.68 g 
C) 10.43 g 
D) 4)17 g 
E) 15.64 g

Question 17

________________________________________uses a small volume of chromatographic stationary phase or molecularly imprinted polymer to isolate analytes from the sample matrix to simply analysis.

Accepted Answer

A) Solid-phase extraction 
B) Polymer extraction 
C) Chromatographic extraction 
D) Antigen extraction 
E) Solvent-free extraction 
A) Solid-phase extraction 
B) Polymer extraction 
C) Chromatographic extraction 
D) Antigen extraction 
E) Solvent-free extraction

Question 18

Which samplng term is incorrectly defined?

Accepted Answer

A) laboratory sample - smaller,homogeneous sample taken from the bulk and has the same composition as the bulk 
B) lot - the total material from which samples are taken 
C) aliquot - small portions of the bulk sample taken for individual analysis 
D) sample preparation - the series of steps that convert a representative bulk sample into a form suitable for analysis 
E) bulk sample - representative sample taken from the lot for analysis or archiving 
A) laboratory sample - smaller,homogeneous sample taken from the bulk and has the same composition as the bulk 
B) lot - the total material from which samples are taken 
C) aliquot - small portions of the bulk sample taken for individual analysis 
D) sample preparation - the series of steps that convert a representative bulk sample into a form suitable for analysis 
E) bulk sample - representative sample taken from the lot for analysis or archiving

Question 19

For random errors,the overall variance,   ,is calculated from the analytical variance,   ,and the sampling variance,   .Which is the correct equation for calculating the overall variance?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Exam 29: Sample Preparation

____________________ dissolves substances that will not dissolve in acid in a hot,molten inorganic____________________.

All of the following are used to grind solids into a fine powder,except:

How many replicates must be completed for sampling deviation of 3.5% to achieve a 1% standard deviation?

Which of the following is INCORRECT for decomposition of organic substances?

____________________ is the procedure in which analyte is chemically modified to make the compound easier to detect or separate.

A mixture contains 5% NaCl particles and 95% NaBr particles.If 103 particles are taken,what is the relative standard deviation for NaCl and NaBr?

Which of the following are NOT liquid extraction techniques? I emulsive liquid-liquid microextraction II dispersive liquid-liquid microextraction III solid-supported liquid-liquid extraction IV supercritical fluid extraction V solid-liquid microextraction

All of the following are true for dissolving inorganic materials in acid,except:

Sample storage is an important aspect of sample preparation.Which is NOT true for sample storage?

What mass of a solid sample containing 2.5% analyte particles and 97.5% solvent particles must be taken to give a standard deviation of 2% of the number of analyte particles,if the average particle volume is 2.54 nL and the sample has an average density of 1.548 g/mL?

What mass will give a sampling standard deviation of 3.5% for a sampling constant of 40.9?

A mixture contains 2.5% KBr and 97.5% inert particles.What is the relative standard deviation for KBr is 50 000 particles are taken?

Calculate the overall standard deviation if the analytical standard deviation is 6% and the sampling standard deviation is 4%.

To calculate the number of required replicates for analysis the equation is used.Which statement is NOT true for the equation and calculation?

Sample preparation of a laboratory sample can involve all of the following,except:

A 4.17 g sample has a 4% sampling standard deviation.What mass sample must be taken to decrease the sampling standard deviation to 2%?

________________________________________uses a small volume of chromatographic stationary phase or molecularly imprinted polymer to isolate analytes from the sample matrix to simply analysis.

Which samplng term is incorrectly defined?

For random errors,the overall variance, ,is calculated from the analytical variance, ,and the sampling variance, .Which is the correct equation for calculating the overall variance?

The Analytical Process

Chemical Measurements

Tools of the Trade

Experimental Error

Statistics

Quality Assurance and Calibration Methods

Chemical Equilibrium

Let the Titrations Begin

Activity and the Systematic Treatment of Equilibrium

Monoprotic Acid-Base Equilibria

Polyprotic Acid-Base Equilibria

Acid-Base Titrations

Edta Titrations

Advanced Topics in Equilibrium

Fundamentals of Electrochemistry

Electrodes and Potentiometry

Redox Titrations

Electroanalytical Techniques

Fundamentals of Spectrophotometry

Applications of Spectrophotometry

Spectrophotometers

Atomic Spectroscopy

Mass Spectrometry

Introduction to Analytical Separations

Gas Chromatography

High-Performance Liquid Chromatography

Chromatographic Methods and Capillary Electrophoresis

Gravimetric and Combustion Analysis

Filters

dissolves substances that will not dissolve in acid in a hot,molten inorganic.

A mixture contains 5% NaCl particles and 95% NaBr particles.If 10³ particles are taken,what is the relative standard deviation for NaCl and NaBr?