Download OBETA CHINONSO FAVOUR. 16/SCI14/018. GEOLOGY. CHM 221

OBETA CHINONSO FAVOUR.
16/SCI14/018.
GEOLOGY.
CHM 221 ASSIGNMENT.
1. Thermal stability also describes, as defined by Schmidt (1928), [1] the stability of a water body and its
resistance to mixing. This is the amount of work needed to transform the water body (e.g. a lake) to a
uniform water density (reference: wikipedia.com). It is the decomposition of a compound on heating.
The higher the temperature needed to decompose something, the more thermally stable it is
(reference: thestudentroom.co.uk)
2.
𝑁𝑖(𝐶𝑂)4
𝐹𝑒(𝐶𝑂) 5
𝐶𝑟(𝐶𝑂)6
Diagrams from Wikipedia and PubChem.
3. Metals can be extracted from their metal ores by:
I. Electrolysis of their molten chlorides for metals like sodium, magnesium, calcium and potassium.
ii. Reduction of oxides using carbons for metals like zinc, iron, tin, lead and copper.
iii. Roasting of the ore by heating alone for metals like mercury, silver, gold and platinum.
4. The six properties of metal carbonyl are:
i. They are fairly air stable.
ii. Most of them obey the 18-electron rule and those that don’t are usually stored in nitrogen.
iii. Their stability appeared to be kinetic or thermodynamic.
iv. They are all toxic if swallowed.
v. Most of them are soluble in organic solvent.
vi. Most of them are crystalline solid except for such as Iron carbonyl 𝐹𝑒𝐶𝑂5 , Osmium carbonyl 𝑂𝑠𝐶𝑂5
which are liquid.
5. 𝑀𝑜24 𝑂37 + 𝑀𝑛𝑂4 − → 𝑀𝑜𝑂3 + 𝑀𝑛2+
𝑀𝑜24 𝑂37 → 𝑀𝑜𝑂3 (oxidation)
𝑀𝑛𝑂4 −→ 𝑀𝑛2+ (reduction)
70𝑒 − + 35𝐻2 𝑂 + 𝑀𝑜24 𝑂37 → 24𝑀𝑜𝑂3 + 70𝐻 + + 70𝑒 −
(x5)
5𝑒 − + 8𝐻 + + 𝑀𝑛𝑂4 − → 𝑀𝑛2+ + 4𝐻2 𝑂
(x70)
175𝐻2 𝑂 + 5𝑀𝑜𝑂24 𝑂37 → 120𝑀𝑜𝑂3 + 350𝐻 + + 350𝑒 −
350𝑒 − + 560𝐻 + + 70𝑀𝑛𝑂4 −→ 70𝑀𝑛2+ + 280𝐻2 𝑂
5𝑀𝑜24 𝑂37 + 70𝑀𝑛𝑂4 − + 210𝐻+→ 120𝑀𝑜𝑂3 + 105𝐻2 𝑂 + 70𝑀𝑛2+
6a. 𝑁𝑎2 𝑺𝟒 𝑂6
(+1)2 + 4(S) + 6(-2) =0
2 + 4S - 12 = 0
4S = +12 - 2
4S = +10
S = 10/4
S = +2.5
S ≈ +3.
6b. 𝑽𝑂2
V + (-2)2 = 0
V–4=0
V = +4.
6c. 𝑷2 𝑂7
2(P) + (-2)7 = 0
2P – 14 = 0
2P = +14
P = 14/2
P = +7.
8. The periodic table is a table of the chemical elements arranged in order of atomic numbers, usually in
rows so that elements with similar atomic structure (and hence similar chemical properties) appear in
vertical columns. It is the tabular arrangement of the chemical elements ordered by their atomic
numbers (number of protons), electron configurations and recurring chemical properties.
9. The atomic radius is the distance from the atomic nucleus to the outermost stable electron orbital in
an atom that is at equilibrium. The atomic radii tend to decrease across a period from left to right. The
atomic radius usually increases while going down a group due to the addition of a new energy level
(shell).
The ionization energy is the minimum amount of energy required to remove one electron from each
atom in a mole of atoms in the gaseous state. There will be an increase of ionization energy from left to
right of a given period and a decrease from top to bottom.
The electron affinity of an atom can be described either as the energy gained by an atom when an
electron is added to it, or conversely as the energy required to detach an electron from a singly charged
anion. It increases from left to right across the period.
Electronegativity is a measure of the ability of an atom or molecule to attract pairs of electrons in the
context of a chemical bond. The type of bond formed is largely determined by the difference in
electronegativity between the atoms involved, using the Pauling scale. Trend-wise, as one moves from
left to right across a period in the periodic table, the electronegativity increases due to the stronger
attraction that the atoms obtain as the nuclear charge increases. Moving down in a group, the
electronegativity decreases due to the longer distance between the nucleus and the valence electron
shell, thereby decreasing the attraction, making the atom have less of an attraction for electrons or
protons.
10. Electronic configuration is the distribution of electrons of an atom or molecule (or other physical
structure) in atomic or molecular orbitals.
11. The electronic configurations of the following elements are:
i. Ca : 1𝑠 2 2𝑠 2 2𝑝6 3𝑠 2 3𝑝6 4𝑠 2
ii. Al : 1𝑠 2 2𝑠 2 2𝑝6 3𝑠 2 3𝑝1
iii. P : 1𝑠 2 2𝑠 2 2𝑝6 3𝑠 2 3𝑝3