FINAL EXAM MATERIAL

Question 1

what do mineral stability diagrams allow us to do?

Answer 1

determine the geologic conditions in which
minerals can coexist at equilibrium
* determine which minerals (solids) are stable or
unstable in a particular geochemical environment
1

Question 2

what are mineral stability diagrams also called?

Answer 2

Activity diagrams

Question 3

describe the stability of the products/reactants in a foward reaction

Answer 3

• reactant minerals are unstable
• product minerals are stable

Question 4

what happens at the triple point of a mineral stability diagram?

Answer 4

all species coexist

Question 5

what do the role of axes play in mineral stability diagrams?

Answer 5

define the ions and acid in solution (the solution chemistry)

Question 6

do solids/pure water participate in LMA?

Answer 6

NO!!

Question 7

how are the lines in a mineral stability diagram defined?

Answer 7

they are defined by the LMA equations for the equilibrium reactions between two mineral phases

Question 8

what are the areas between the lines in a mineral stability diagram?

Answer 8

mineral stability fields

Question 9

what is the following definitions term

a large and highly diversified group of aluminosilicates
that occur in certain igneous, metamorphic, and sedimentary rocks.

Answer 9

the zeolites

Question 10

how do zeolites form?

Answer 10

m by direct precipitation from aqueous solution in vesicles and fractures of lava flows and in
sedimentary rocks

Question 11

in what situation would you get a line in a mineral stability diagram that is curved?

Answer 11

closed systems with small water/rock ratios

Question 12

what is the reaction pathway dependent on?

Answer 12

the initial chemical composition and pH of the water

Question 13

what would cause a silicate mineral to dissolve incongruently?

Answer 13

being exposed to acidified waters

Question 14

what are some examples of secondary minerals and how do they form?

Answer 14

they form when they are exposed to acidified waters and dissolve incongruently
clay and zeolite minerals are examples

Question 15

what is the following definitions term?

describes conditions under which
a mineral is stable or dissolves.

Answer 15

Solubility diagrams

Question 16

what is the following definitions term?

no secondary mineral phase
forms, all minerals dissolve congruently in pure water.

Answer 16

congruent reaction

Question 17

what is the following definitions term?

a secondary mineral phase
forms as a result of the concentration of certain ions in
solution

Answer 17

incongruent reaction

Question 19

chapter 13

Question 20

how do clay minerals typically crystallize?

Answer 20

phyllosilicates

Question 21

what family do clay minerals belong?

Answer 21

aluminosilicates

Question 22

what three groups can clay minerals be divided into?

Answer 22

• platy clay minerals (phyllosilicates)
• Fibrous clay minerals
• amorphous clays

Question 23

what group of clay mineral is being described below?

most abundant group (e.g., smectite, kaolinite)
* two-layer (1:1), three-layer (2:1), mixed-layer

Answer 23

platy clay minerals (phyllosilicates)

Question 24

what group of clay mineral is being described below?

sepiolite and palygorskite (attapulgite)

Answer 24

fibrous clay minerals

Question 25

what group of clay mineral is being described below? allophane, is an aluminosilicate of variable chemical composition that is amorphous to x-rays

Answer 25

amorphous clays

Question 26

what is being described below? consist of two types of layers of different chemical composition and coordination.

Answer 26

phyllosilicates

Question 27

what types of sheets compose phyllo silicates?

Answer 27

tetrahedral sheet (T) octahedral sheet (O)

Question 28

what type of phyllosilicate layer is being described composed of aluminum hydroxide

Answer 28

octahedral layer (O)

Question 29

wat type of phyllosilicate layer is being described? composed of silica tetrahedra

Answer 29

tetrahedral layer

Question 30

what is being described below? occurs when an atom or ion is replaced by another of similar size but different charge. This results in the overall structure having a (negative) charge.

Answer 30

isomorphic substitution

Question 31

what can the octahedral sheet layer be divided into?

Answer 31

- trioctahedral - dioctahedral

Question 32

what division of the octahedral sheet is being described below? all positions in the octahedral layer are filled

Answer 32

trioctahedral

Question 33

what division of the octahedral sheet is being described below? two of every three available sites are filled

Answer 33

dioctahedral

Question 34

tetrahedral and octahedral layer join to form:

Answer 34

- two layer clays - three layer clays - mixed layer clays

Question 35

what layer clay is being described below? permit very little substitution of either Al3+ or Si4+ (e.g., kaolinites)

Answer 35

two layer (1:1) clays

Question 36

what layer of clay is being described below? with the exception of pyrophyllite, are characterized by extensive substitutions in either the octahedral layer or the tetrahedral layer, or in both (e.g., smectites)

Answer 36

three-layer clays (2:1)

Question 37

what layer of clay is being described below? that are mixtures of different two-layer (1:1) and three-layer (2:1) clays.

Answer 37

mixed layer clays

Question 38

what is the following definitions term? : on the surfaces and edges of clay tetrahedral-octahedral sheets there are unshared oxygen atoms, which each have a 2- charge

Answer 38

edge charges

Question 39

what is the following definitions term? the process by which a solid holds molecules of a gas or liquid or solute as a thin film

Answer 39

adsorption

Question 40

what is the following definitions term? is a measure of the clay mineral’s ability to attract/hold cations. It can be calculated from the net negative charge of the mineral’s chemical formula at neutral pH.

Answer 40

cation exchange capacity (CEC)

Question 41

what is the following definitions term? all members of the dioctahedral subgroup have the same chemical composition but different crystal structures

Answer 41

polymorphs

Question 42

what is the following definition? – when this clay is exposed to water it expands, commonly referred to as a

Answer 42

swelling clay

Question 43

what is the following definitions term? layer that bonds the T-O-T sheets together

Answer 43

interlayer

Question 44

what does it mean for a mineral to be authgenic?

Answer 44

forms in sediment pore waters

Question 45

what does it mean for a mineral to be a secondary/diagenetic mineral?

Answer 45

formed by the alteration of other clay minerals

Question 46

chapter 14

Question 47

what is the following definitions term? involve the loss and gain of e- . These reactions typically involve minor and trace elements and their ions

Answer 47

redox reactions

Question 48

what is the loss of an electron called?

Answer 48

oxidation

Question 49

what is the gain of an electron called?

Answer 49

reduction

Question 50

what is the following definitions term? donate electrons and are oxidized, oxidation state goes from a lower number to a higher number.

Answer 50

reducing agents

Question 51

what is the following definitions term? accepts electrons and is reduced, oxidation state goes from higher number to a lower number.

Answer 51

oxidizing agent

Question 52

what happens to an atom if it donates an electron?

Answer 52

it is oxidized

Question 53

what happens to an atom if it accepts an electron?

Answer 53

gets reduced

Question 54

what is the following definitions term? mining of ore materials exposes sulfides to water and air, together they react to form sulfuric acid which dissolves into harmful metals. can happen anywhere sulfides are exposed to water and air

Answer 54

acid mine drainage

Question 55

what is the following definitions term? ranks which elements are stronger reducing agents (electron donors) relative to other elements.

Answer 55

electromotive series

Question 56

what is the electromotive series ranking based on?

Answer 56

gibbs free energy of reactions

Question 57

half reaction

Question 58

what is the following definitions term? oxidation-reduction reactions can be split into two complementary half reactions that can be physically separated to from an

Answer 58

electrochemical cell

Question 59

what is the following terms definition? ___________________ measured as voltage (v) is generated by the electrical potential between the electrodes (generated by the half-reactions

Answer 59

electromotive force (emf)

Question 60

what is the following definitions term? a convention in which the emf generated by the dissociation of H2 gas into H+ in the standard state is arbitrarily set equal to zero

Answer 60

the standard electrode

Question 61

what is the following definitions term? the emf (in V) generated by an electrode in the standard state relative to the H2 electrode in the standard state

Answer 61

the standard electrode potential