Med Tech Exam Review - Clinical
Chemistry Exam Questions With Correct
Answers
In the analytic technique of potentiometry, a comparison is made between the
| | | | | | | | | | | |
voltage of one half-cell connected to another half-cell. It is customary that all
| | | | | | | | | | | | |
half-cell potentials be compared to the potential generated by a standard
| | | | | | | | | | |
electrode. This standard electrode is: | | | | |
a. A hydrogen electrode
| | |
b. a calcium electrode
| | |
c. a potassium electrode
| | |
d. a copper electrode
| | | |
e. an iron electrode - CORRECT ANSWER✔✔-A. a half-cell, also called an
| | | | | | | | | | | |
electrode, is composed of a single metallic conductor surrounded by a solution of
| | | | | | | | | | | |
electrolyte. An electrochemical cell consists of two half-cells. If two different
| | | | | | | | | | | |
kinds of half-cells are connected in such a way as to make a complete circuit, a
| | | | | | | | | | | | | | | |
current will flow because of the potential difference between the two electrodes.
| | | | | | | | | | | |
The connection must be between the two electrolyte solutions, usually by means
| | | | | | | | | | | |
of a salt bridge. The universally accepted standard half-cell with which all other
| | | | | | | | | | | | |
half-cells are compared is the hydrogen electrode, arbitrarily assigned a potential
| | | | | | | | | | |
E of 0.000 volt
| | |
in an electrolytic cell, the half-cell where reduction takes place is known as the
| | | | | | | | | | | | |
a. anode|
,b. cathode
|
c. inidcating electrode
| |
d. reference electrode
| |
e. standard electrode - CORRECT ANSWER✔✔-B. oxidation involves the loss of
| | | | | | | | | | |
electrons, and reduction the gain of electrons. In an electolytic cell composed of
| | | | | | | | | | | | |
two different half-cells - for example, zinc in zinc sulfate and copper in copper
| | | | | | | | | | | | | |
sulfate - electrons will flow from the anode to the cathode. thus reduction takes
| | | | | | | | | | | | | |
place at the cathode
| | |
mercury covered by a layer of mercurous chloride in contact with satruated
| | | | | | | | | | | |
potassium chloride solution is a description of which of the following types of
| | | | | | | | | | | | |
electrodes?
a. antimony
|
b. calomel
|
c. hydrogen
|
d. quinhydrone
|
e. silver/silver chloride - CORRECT ANSWER✔✔-B. In practical applications of
| | | | | | | | | |
potentiometry, it is desirable to use one half-cell with a known and constant
| | | | | | | | | | | | |
potential that is not sensitive to the composition of th ematerial to be analyzed.
| | | | | | | | | | | | | |
This is called the reference electrode. One common reference electrode is the
| | | | | | | | | | | |
calomel electrode, which consists of mercury covered by a layer of mercurous
| | | | | | | | | | | |
chloride in contact with a saturated solution of potassium chloride. The other
| | | | | | | | | | | |
half-cell, called the indicator electrode, is selected on the basis of the change in
| | | | | | | | | | | | | |
its potential with change in the concentration of the analyte of interest
| | | | | | | | | | |
when the pH-sensitive glass electrode is not actively in use, it should be kept in
| | | | | | | | | | | | | |
a. distilled or deionized water
| | | |
,b. physiologic saline solution
| | |
c. the medium recommended by the manufacturer
| | | | | |
d. a buffer solution with a pH near the pH of the internal solution in the electrode
| | | | | | | | | | | | | | | |
e. a buffer solution with a pH near the pH at which the electrode is to be used -
| | | | | | | | | | | | | | | | | | |
CORRECT ANSWER✔✔-C. for optimum performance, pH-sensitive glass
| | | | | | |
electrodes that are not actively in use should be kep timmersed in an aqueous
| | | | | | | | | | | | | |
medium. Since the exact composition of the pH-sensitive glass varies from one
| | | | | | | | | | | |
manufacturer to another, the glass electrode should be maintained in the
| | | | | | | | | | |
medium recommended by the manufacturer. Usual media are water, dilute HCl,
| | | | | | | | | | |
and buffer with a pH near the pH of the solution to be measured. The functioning
| | | | | | | | | | | | | | |
of a glass electrode depends on the properties of the pH-sensitive glass. A typical
| | | | | | | | | | | | | |
glass electrode is made by sealing a thin piece of pH-sensitive glass at the end of
| | | | | | | | | | | | | | | | |
a piece of glass tubing and filling the tube with a solution of hydrochloric acid
| | | | | | | | | | | | | | |
saturated with silver chloride. A silver wire is immersed in the solution in the tube
| | | | | | | | | | | | | |
with one end extending outside the tube for external connection. This is
| | | | | | | | | | | | |
essentially a silver/silver chloride reference electrode sealed within the tube with
| | | | | | | | | | |
the pH-sensitive glass tip. This pH-sensitive glass functions appropriately only
| | | | | | | | | |
when it is saturated with water. Then eac surface of the glass develops a hydrated
| | | | | | | | | | | | | |
latice, where exchange of alkaline metal ions in the lattice for hydrogen ions in
| | | | | | | | | | | | | | |
the test solution can occur
| | | |
Colligative properties of solutions include all of the following except:
| | | | | | | | | |
a. boiling point
| |
b. freezing point
| |
c. pH | |
d. osmotic pressure
| |
e. vapor pressure - CORRECT ANSWER✔✔-C. colligative properties of a solution
| | | | | | | | | | |
are those properties that depend only on the number of particles in solution, not
| | | | | | | | | | | | | |
on the nature of the particles. The colligative properties are boiling point, freezing
| | | | | | | | | | | |
, |point, osmotic pressure, and vapor pressure. Terms used to describe the
| | | | | | | | | | |
concentration of particles in solution are osmole (the number of particles,
| | | | | | | | | | |
6.0224x10^23, that lowers the freezing point 1.86C) and osmolal (the| | | | | | | | | |
concentration of 1 osm of solute per kilogram of water). One mole of an
| | | | | | | | | | | | | |
unionized solute dissolved in 1 kg of water lowers the freezing pont 1.86C. thus it
| | | | | | | | | | | | | | |
is an osmolal solution. For un-ionized substances such as glucose, 1 mol equals 1
| | | | | | | | | | | | | |
osm. For substances that ionize, such as sodium chloride, werein each molecule
| | | | | | | | | | | |
in solution becomes two ions and thus two particles, 1 mol of sodium chloride
| | | | | | | | | | | | | |
theoretically equals 2 osm. In practice, howerever, this is not always the case; an
| | | | | | | | | | | | | |
osmotic activit coefficient factor is used to correct for the deviation
| | | | | | | | | |
the freezing point osmometer is based on the principle that
| | | | | | | | | |
a. the freezing point depression is inversely proportional to the amount of solute
| | | | | | | | | | | | |
in the solution
| |
b. the freezing point depression varies as the logarithm of the concenration of
| | | | | | | | | | | | |
solute
c. the freezing point is raised by an amount that is inversely proportional to the
| | | | | | | | | | | | | | |
concentration of dissolved particles in the solution | | | | | |
d. the freezing point is lowered by an amount that is directly proportional to the
| | | | | | | | | | | | | | |
concentration of dissolved particles in the solution | | | | | | |
e. there is no relationship between freezing point depression and the
| | | | | | | | | | |
concentration of dissolved particles in the solution - CORRECT ANSWER✔✔-D. the
| | | | | | | | | |
|freezing point of an aqueous solution is lowered 1.86C for every osmole of
| | | | | | | | | | | | |
dissolved particles per kilogram of water. These particles may be ions, for
| | | | | | | | | | | |
example. Na+ and Cl-, or undissociated molecules such as glucose. The freezing
| | | | | | | | | | | |
point osmometer is an instrument designed to measure the freezing point of
| | | | | | | | | | | |
solutions. It uses a thermistor that is capable of measuring very small changes in
| | | | | | | | | | | | | |
temperature
Chemistry Exam Questions With Correct
Answers
In the analytic technique of potentiometry, a comparison is made between the
| | | | | | | | | | | |
voltage of one half-cell connected to another half-cell. It is customary that all
| | | | | | | | | | | | |
half-cell potentials be compared to the potential generated by a standard
| | | | | | | | | | |
electrode. This standard electrode is: | | | | |
a. A hydrogen electrode
| | |
b. a calcium electrode
| | |
c. a potassium electrode
| | |
d. a copper electrode
| | | |
e. an iron electrode - CORRECT ANSWER✔✔-A. a half-cell, also called an
| | | | | | | | | | | |
electrode, is composed of a single metallic conductor surrounded by a solution of
| | | | | | | | | | | |
electrolyte. An electrochemical cell consists of two half-cells. If two different
| | | | | | | | | | | |
kinds of half-cells are connected in such a way as to make a complete circuit, a
| | | | | | | | | | | | | | | |
current will flow because of the potential difference between the two electrodes.
| | | | | | | | | | | |
The connection must be between the two electrolyte solutions, usually by means
| | | | | | | | | | | |
of a salt bridge. The universally accepted standard half-cell with which all other
| | | | | | | | | | | | |
half-cells are compared is the hydrogen electrode, arbitrarily assigned a potential
| | | | | | | | | | |
E of 0.000 volt
| | |
in an electrolytic cell, the half-cell where reduction takes place is known as the
| | | | | | | | | | | | |
a. anode|
,b. cathode
|
c. inidcating electrode
| |
d. reference electrode
| |
e. standard electrode - CORRECT ANSWER✔✔-B. oxidation involves the loss of
| | | | | | | | | | |
electrons, and reduction the gain of electrons. In an electolytic cell composed of
| | | | | | | | | | | | |
two different half-cells - for example, zinc in zinc sulfate and copper in copper
| | | | | | | | | | | | | |
sulfate - electrons will flow from the anode to the cathode. thus reduction takes
| | | | | | | | | | | | | |
place at the cathode
| | |
mercury covered by a layer of mercurous chloride in contact with satruated
| | | | | | | | | | | |
potassium chloride solution is a description of which of the following types of
| | | | | | | | | | | | |
electrodes?
a. antimony
|
b. calomel
|
c. hydrogen
|
d. quinhydrone
|
e. silver/silver chloride - CORRECT ANSWER✔✔-B. In practical applications of
| | | | | | | | | |
potentiometry, it is desirable to use one half-cell with a known and constant
| | | | | | | | | | | | |
potential that is not sensitive to the composition of th ematerial to be analyzed.
| | | | | | | | | | | | | |
This is called the reference electrode. One common reference electrode is the
| | | | | | | | | | | |
calomel electrode, which consists of mercury covered by a layer of mercurous
| | | | | | | | | | | |
chloride in contact with a saturated solution of potassium chloride. The other
| | | | | | | | | | | |
half-cell, called the indicator electrode, is selected on the basis of the change in
| | | | | | | | | | | | | |
its potential with change in the concentration of the analyte of interest
| | | | | | | | | | |
when the pH-sensitive glass electrode is not actively in use, it should be kept in
| | | | | | | | | | | | | |
a. distilled or deionized water
| | | |
,b. physiologic saline solution
| | |
c. the medium recommended by the manufacturer
| | | | | |
d. a buffer solution with a pH near the pH of the internal solution in the electrode
| | | | | | | | | | | | | | | |
e. a buffer solution with a pH near the pH at which the electrode is to be used -
| | | | | | | | | | | | | | | | | | |
CORRECT ANSWER✔✔-C. for optimum performance, pH-sensitive glass
| | | | | | |
electrodes that are not actively in use should be kep timmersed in an aqueous
| | | | | | | | | | | | | |
medium. Since the exact composition of the pH-sensitive glass varies from one
| | | | | | | | | | | |
manufacturer to another, the glass electrode should be maintained in the
| | | | | | | | | | |
medium recommended by the manufacturer. Usual media are water, dilute HCl,
| | | | | | | | | | |
and buffer with a pH near the pH of the solution to be measured. The functioning
| | | | | | | | | | | | | | |
of a glass electrode depends on the properties of the pH-sensitive glass. A typical
| | | | | | | | | | | | | |
glass electrode is made by sealing a thin piece of pH-sensitive glass at the end of
| | | | | | | | | | | | | | | | |
a piece of glass tubing and filling the tube with a solution of hydrochloric acid
| | | | | | | | | | | | | | |
saturated with silver chloride. A silver wire is immersed in the solution in the tube
| | | | | | | | | | | | | |
with one end extending outside the tube for external connection. This is
| | | | | | | | | | | | |
essentially a silver/silver chloride reference electrode sealed within the tube with
| | | | | | | | | | |
the pH-sensitive glass tip. This pH-sensitive glass functions appropriately only
| | | | | | | | | |
when it is saturated with water. Then eac surface of the glass develops a hydrated
| | | | | | | | | | | | | |
latice, where exchange of alkaline metal ions in the lattice for hydrogen ions in
| | | | | | | | | | | | | | |
the test solution can occur
| | | |
Colligative properties of solutions include all of the following except:
| | | | | | | | | |
a. boiling point
| |
b. freezing point
| |
c. pH | |
d. osmotic pressure
| |
e. vapor pressure - CORRECT ANSWER✔✔-C. colligative properties of a solution
| | | | | | | | | | |
are those properties that depend only on the number of particles in solution, not
| | | | | | | | | | | | | |
on the nature of the particles. The colligative properties are boiling point, freezing
| | | | | | | | | | | |
, |point, osmotic pressure, and vapor pressure. Terms used to describe the
| | | | | | | | | | |
concentration of particles in solution are osmole (the number of particles,
| | | | | | | | | | |
6.0224x10^23, that lowers the freezing point 1.86C) and osmolal (the| | | | | | | | | |
concentration of 1 osm of solute per kilogram of water). One mole of an
| | | | | | | | | | | | | |
unionized solute dissolved in 1 kg of water lowers the freezing pont 1.86C. thus it
| | | | | | | | | | | | | | |
is an osmolal solution. For un-ionized substances such as glucose, 1 mol equals 1
| | | | | | | | | | | | | |
osm. For substances that ionize, such as sodium chloride, werein each molecule
| | | | | | | | | | | |
in solution becomes two ions and thus two particles, 1 mol of sodium chloride
| | | | | | | | | | | | | |
theoretically equals 2 osm. In practice, howerever, this is not always the case; an
| | | | | | | | | | | | | |
osmotic activit coefficient factor is used to correct for the deviation
| | | | | | | | | |
the freezing point osmometer is based on the principle that
| | | | | | | | | |
a. the freezing point depression is inversely proportional to the amount of solute
| | | | | | | | | | | | |
in the solution
| |
b. the freezing point depression varies as the logarithm of the concenration of
| | | | | | | | | | | | |
solute
c. the freezing point is raised by an amount that is inversely proportional to the
| | | | | | | | | | | | | | |
concentration of dissolved particles in the solution | | | | | |
d. the freezing point is lowered by an amount that is directly proportional to the
| | | | | | | | | | | | | | |
concentration of dissolved particles in the solution | | | | | | |
e. there is no relationship between freezing point depression and the
| | | | | | | | | | |
concentration of dissolved particles in the solution - CORRECT ANSWER✔✔-D. the
| | | | | | | | | |
|freezing point of an aqueous solution is lowered 1.86C for every osmole of
| | | | | | | | | | | | |
dissolved particles per kilogram of water. These particles may be ions, for
| | | | | | | | | | | |
example. Na+ and Cl-, or undissociated molecules such as glucose. The freezing
| | | | | | | | | | | |
point osmometer is an instrument designed to measure the freezing point of
| | | | | | | | | | | |
solutions. It uses a thermistor that is capable of measuring very small changes in
| | | | | | | | | | | | | |
temperature
