NGT34 Chemistry Funds

Question 0

A solution can exist in which of the following states:

Answer 0

Liquid
Solid
Gas

Question 1

Explain why solutions are classified as a mixture and not a compound.

Answer 1

A solution is classified as a mixture because the composition is not of fixed
proportion, and the components are not chemically bonded.

Question 2

Define mixture

Answer 2

A mixture consists of two or more substances combined with no constant percentage
of composition. Each component retains its original properties and there are no
chemical bonds between the components.

Question 3

Define compound

Answer 3

Compounds are substances containing more than one constituent element and
having properties different from those of the individual elements. The composition of
a specific compound is always definite and the components are chemically bonded.

Question 4

Describe the differences, if any, between a mixture and a compound.

Answer 4

The major differences are the substances in a compound are chemically combined
in definite proportions and have properties that are different from the original
elements. The substances in a mixture can be combined in any proportion, and
each substance retains its original properties (or words to this effect).

Question 5

Define pH.

Answer 5

pH is defined as the negative logarithm of the hydrogen ion concentration in
moles/liter.

Question 6

Define conductivity.

Answer 6

Conductivity is a measure of a substance’s ability to conduct electricity. It is the
inverse of the resistivity or the measure of the resistance to the flow of electricity.

Question 7

Explain the concept of pH.

Answer 7

Describes the relative acidity or alkalinity of a solution.

Question 8

Explain the measurement scale for pH in terms of an acidic solution, a neutral solution, and a basic or alkaline
solution.

Answer 8

Using the pH definition, it follows that the pH of pure water at 25°C is 7 neutral. pH
values less than 7 indicate an acidic solution. pH values greater than 7 indicate a
basic or alkaline solution.

Question 9

Where on the pH scale would a solution containing a weak acid be indicated?

Answer 9

pH value less than 7

Question 10

Conductivity is defined as?

Answer 10

The measure of a substance’s ability to conduct electricity.

Question 11

Define the term Gas

Answer 11

A gas is a fluid (as air) that has neither independent shape nor volume but
tends to expand indefinitely.

Question 12

Describe the Ideal Gas Law

Answer 12

The Ideal Gas Law describes the relationship between the pressure,
temperature, and volume of a given gas.

Question 13

What is the Law of Partial Pressure?

Answer 13

The Law of Partial Pressure says the sum of all of the partial pressures of
the gasses in a volume is equal to the total pressure.

Question 14

If the temperature of an H2,storage tank is increased, what will the pressure in the storage tank do? (Increase, decrease, or remain the same)?

Answer 14

Increase

Question 15

A piston-cylinder arrangement has a 4ft3 volume and a pressure of 30 psig and is filled with air. The piston moves into the cylinder to establish a new volume of 3ft3. Which one of the following best identifies the new pressure inside the cylinder? (Assume temperature remains constant and atmospheric pressure is 15 psi.)

Answer 15

45 psig

Question 16

Which one of the following would most likely be used as a cover gas and purge gas to remove oxygen from tank
atmospheres?

Answer 16

Nitrogen

Question 17

Which gas is the most likely to be used to control oxygen in the primary system?

Answer 17

Hydrogen

Question 18

Which one of the following best describes a term for a fluid that has neither independent shape nor volume but tends
to expand indefinitely?

Answer 18

Gas

Question 19

List three methods for reducing the rate of corrosion.

Answer 19

Maintaining oxygen concentrations within
specification.
Controlling the pH.
Adding a corrosion inhibitor.

Question 20

Describe galvanic corrosion.

Answer 20

Galvanic corrosion is the disintegration or decay of a metal, which results when metals with dissimilar electrochemical potentials are in electrical contact in an electrolyte.

Question 21

What corrodent is required to be present for Stress Corrosion Cracking to take place in stainless steel?

Answer 21

Chloride

Question 22

What is Microbiologically Influenced Corrosion?

Answer 22

MIC is a type of corrosion wherein the conditions required for corrosion occur due to the presence of living organisms.

Question 23

The attack, or eating away, of metals as a result of an electrochemical reaction between the metal and its
environment best defines which of the following?

Answer 23

Corrosion

Question 24

Which one of the following best describes a method used to control general corrosion?

Answer 24

Do not use air-saturated make-up water.

Question 25

Which one of the following best describes the development of the passive oxide layer?

Answer 25

Ferrous ions in contact with water form ferrous hydroxide molecules that decompose to form magnetite at temperatures greater than 120 F.

Question 26

What best describes the process of ion exchange?

Answer 26

Ions are sent through an ion exchanger where they are replaced with the counter ions in the resin.

Question 27

A result of proper demineralizer operation on water with ionic impurities is that the exiting water will always have?

Answer 27

Lower conductivity

Question 28

Positively charged ions are called _____________, and negatively charged ions are ________________.

Answer 28

Cations and Anions

Question 29

Describe how the ion exchange mechanism works.

Answer 29

Each resin bead has many ion exchange sites. Each site has a fixed charge and a mobile exchangeable counter ion. When an impurity ion comes in contact with the resin bead, the mobile ion will be exchanged with the impurity ion.

Question 30

Does a Cation ion exchanger exchange positive or negatively charged ions?

Answer 30

Cation ion exchanger substitutes positively charged counter ions for positively charged impurity ions.