Test One

Question 1

What are the purpose of nuclear reactions on the composition of the elements on Earth?

Answer 1

Nuclear reactions determine the relative abundance of the elements

Question 2

What do you call the reactions that determine the oxidation states of the elements on the Earth surface?

Answer 2

Electronic reactions

Question 3

What do metal ligand reactions determine

Answer 3

The determine where on Earth that the elements would be located/ found on the Earth’s surface

Question 4

In a graph which shows the abundance of the elements as a function of their atomic number, why is there a noticeable zigzag like pattern?

Answer 4

The zigzag pattern of a relative abundance graph of the elements is due to the fact that even # atomic numbers are usually higher in abundance than odd numbered atomic numbers

Question 5

true or false, the abundance of the first 50 elements decreases

Answer 5

true

Question 6

what elements are anomalously low in relative abundance

Answer 6

Li, Be, B
Lithium
Beryllium
Boron

Question 7

Which element is anomously high

Answer 7

Fe

Iron

Question 8

Which elements have no stable isotopes, state their atomic number

Answer 8

Technitium (43), Tc

Promethium (61), Pm

Question 9

True or false, elements bigger than Bismuth (83) have no stable isotopes

Answer 9

true

Question 10

True or false, elements bigger than Bismuth (83) decay products from long lived isotopes of U (uranium) and Th (thorium)

Answer 10

true

Question 11

True or false, all particularly nasty and toxic elements have a lower relative abundance in the universe

Answer 11

true

Question 12

Give five examples of the nasty, toxic elements in the universe that are low in abundance

Answer 12

Beryllium
Mercury Hg (80)
Arsenic As (33)
Lead Pb (82)
Cd Cadmium (48)

Question 13

Atomic number of Hg

Answer 13

80

Question 14

Atomic number of As

Answer 14

33

Question 15

Atomic number of Pb

Answer 15

82

Question 16

Atomic number Cd

Answer 16

48

Question 17

Where do elements come from

Answer 17

Big Bang and Dead Stars

Question 18

What is the big bang

Answer 18

Rapid expansion and cooling, formation of the universe

Question 19

What happened between 0-1 uS in the big bang

Answer 19

formation of neutrons and protons

Question 20

What happened between 0-20 mins of the big bang

Answer 20

D and He formed when the temperature was not too cold and not too hot

Question 21

what happens in the big bang when its too hot

Answer 21

any deuterium formed will be destroyed

Question 22

what happens when in the big bang it gets too cold

Answer 22

don’t get nuclear fusion

Question 23

Why are elements heavier than helium not formed during the big bang

Answer 23

Not formed during the big bang because of the brief time and an energy gap after He; the Lithium energy barrier is really large (large energy gap between He and Li)

Question 24

How were the other 90 elements formed

Answer 24

the other 90 elements were formed in stars but several processes are involved

Question 25

How are stars formed

Answer 25

Stars are formed when a cloud of interstellar gas contracts under the influences of gravity

Question 26

what happens when the pressure increases in the star's core

Answer 26

the temperature increases

Question 27

What happens when the temperature reaches 20*10^6K

Answer 27

hydrogen fusion can occur and a star is born

Question 28

true or false, for 90% of the life of a star only hydrogen fusion occurs 4 H to He

Answer 28

true

Question 29

what happens 90% of the life of a star

Answer 29

hydrogen fusion occurs

Question 30

true or false, the nuclear reactions that can occur in a star are governed mainly by temperature

Answer 30

true

Question 31

When can elements heavier than He be made

Answer 31

Although the energy that hydrogen fusion provides prevents the gravitational collapse of a star therefore when hydrogen gets depleted the core compresses and the temperature increases thus the conditions will become right for making elements heavier than He (dying star)

Question 32

true or false, intermediate size stars can produce Fe

Answer 32

true

Question 33

how did the solar system form

Answer 33

from contracting and spinning dust cloud

Question 34

what causes the separation of some elements

Answer 34

the gradient between temperature and pressure based on their boiling points; therefore planets closest to the sun are rocky (high bp) while beyond Mars they are gaseous ( low bp)

Question 35

Since its too cold for cold fusion reactions on Earth what determines the behavior of elements on earth

Answer 35

Electron energies

Question 36

true or false, stars are about nuclear reactions whilst planets are about electron energies

Answer 36

true

Question 37

which side of the periodic table are recipients of electrons

Answer 37

on the right hand side

Question 38

which part of the periodic table are elements the most abundant

Answer 38

the even MASS atoms and the first row elements

Question 39

On Earth, which element determines the oxidizing conditions of the planet

Answer 39

Oxygen (pO2)

Question 40

what is the standard reduction potential of O2 reduction

Answer 40

1.23 V

Question 41

what are standard conditions

Answer 41

1 M 1 atm 0 C (or specified temperature)

Question 42

true or false, the more positive E is the most easily that Metal is to reduce

Answer 42

true

Question 43

why do oxides float in comparison to metals

Answer 43

oxides are lighter

Question 44

What is the typical oxidation state of G1 elements on Earth (give example)

Answer 44

+1 (Na and K)

Question 45

what are the typical oxidation states of G2 earth metals and give examples

Answer 45

Mg and Ca

Question 46

G17 oxidation state (give example)

Answer 46

-1 (Cl, Br, etc halides)

Question 47

What is the typical oxidation state of oxygen

Answer 47

0 or -2

Question 48

ox state of Carbon (C) and give examples

Answer 48

-4 to +4 CH4, CO2

Question 49

ox state of Nitrogen (N) give examples

Answer 49

-3 to +5 NH3 to NO3-

Question 50

ox state of Al

Answer 50

+3

Question 51

ox state of Si

Answer 51

+4

Question 52

Ox state of Phosphorous (P)

Answer 52

+5 as PO4-3

Question 53

ox state of S give example

Answer 53

-2 to +6 sulfide to sulfate

Question 54

Ox state of As (Arsenic) give examples

Answer 54

+5 as AsO4 (-3) and +3 (H3AsO3)

Question 55

ox state of Cr

Answer 55

+3 or +6 (Cr+3 or CrO2 2-)

Question 56

ox state Mn

Answer 56

+2, +4,+7 (permanganate)

Question 57

ox state of Fe

Answer 57

+2 or +3 (ferrous or ferric)

Question 58

ox state of Cu

Answer 58

+1 and +2 (cuprous or cupric)

Question 59

Ox state of Zn

Answer 59

+2

Question 60

ox state of Cd

Answer 60

+2

Question 61

true or false, as you move down the sediment the amount of O2 decreases

Answer 61

true

Question 62

In estuarine soils why is the top layer brown

Answer 62

due to Fe being Fe3+ and S being SO4 2-; color due to Fe 3+ oxides

Question 63

What happens at the lower layers of estuarine soils

Answer 63

the bottom layer is black in color; due to fine grained iron sulfides

Question 64

why is the color of the bottom layer of estuarine soils black

Answer 64

Fe 3+ is reduced to Fe2+ and SO4 2- is reduced to S2-; the black is due to fine grained Iron Sulfides

Question 65

true or false, transition metal sulfides are typically very low in solubility

Answer 65

true

Question 66

true or false, the number of waters attached to a cation depends on the size of central cation

Answer 66

true

Question 67

true or false, the protons coordinated to the cation will be more acidic than the protons free

Answer 67

true

Question 68

true or false, if the coordinated water is deprotonated, the charge decreases (eg. Fe3+ to Fe2+)

Answer 68

true

Question 69

true or false, cation precipitation involves removing protons to form a neutral species

Answer 69

true

Question 70

what happens the solubility of cations at low pH and how much H+ ions are present at low pH

Answer 70

at low pH cations are more soluble | H+ conc is high

Question 71

what happens to the solubility of cations at high pH and how much H+ is present

Answer 71

at high pH cations are less soluble | low H+ present in soln

Question 72

how does cation ppt occur (ppt = precipitation)

Answer 72

protons from coordinated water ligands must be removed

Question 73

true or false, cations of high charge density (z/r) lose protons more easily (eg. at lower pH)

Answer 73

true

Question 74

what does it mean if a cation loses protons much easily

Answer 74

it means that ppt formation is more likely and these cations will thus be less soluble

Question 75

soluble or less soluble, low charge (z), large radius (r)

Answer 75

this means it will have a low charge density thus it will be more soluble

Question 76

Would precipitation occur for G1 cations and why

Answer 76

PPT will not occur, this is because Na+ and K+ have a large atomic radii and have a low charge; therefore the H2O coordinated to the cation are NOT acidic, and ppt is not seen

Question 77

what is the effect of precipitation on G2 cations

Answer 77

cations such as Mg 2+ and Ca 2+, are large and have a 2+ charge, this means that the cation coordinated H2O will only be slightly acidic, ppt is seen at HIGH pH. Eg Ca(OH)2 ppt at pH above 12

Question 78

true or false, the higher the charge, the higher the enthalpy of hydration; as with increasing charge atomic radii decrease; more likelihood of deprotonation of water coordinated ligand to metal

Answer 78

true

Question 79

what is the pH of normal rain

Answer 79

5-6

Question 80

what is the pH of acid rain

Answer 80

3 or 4

Question 81

why are oxy anions soluble

Answer 81

this is because the central cation is so highly charged

Question 82

why are the neutral hydroxide complexes acidic when they form oxyanions

Answer 82

because the central charge is high that the complex is acidic