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Main Element In The Earth’s Crust
SM Sains Kimia Analisis Dan Persekitaran
Lecturer: PUAN MAISARAH BINTI JAAFAR
Group members: ABDUL RAHMAN BIN YUSUF UK26406
ZAIIMAH BINTI ROZMAN UK25649SITI SOLEHA BINTI MUSTAFFA UK24901
WAN AZWIRA BINTI AB GHANI @ WAN AHMAD UK26257
NURUL SYAZDIANA BINTI MOHD ZUKI UK26258
Elements Approximate % by weight
Oxygen (O) 46.6
Silicon (Si) 27.7
Aluminum (Al) 8.1
Iron (Fe) 5.0
Calcium (Ca) 3.6
Sodium (Na) 2.8
Potassium (K) 2.6
Magnesium (Mg) 2.1
Abundances of the Elements in the earth’s
crust
Silicon Common element in the earth’s crust Shiny, dark grey with a tint of blue Never found in its natural state, but
rather in combination with oxygen as a silicate ion (SiO) in silica-rich rocks
Example: obsidian, granite, diorite, and sandstone
Recovered from an abundant resource: sand
Most pure sand is quartz, silicon dioxide (SiO2)
Silicon with oxygen• Silicon occurs mainly in nature as the oxide
and silicates.• Silicates are compound containing a silicon
bearing an anion.• Silicon reacts with oxygen become silicates, SiO .• Minerals containing silica, known as silicates• Examples: • quartz (SiO2) and olivine (FeSiO4) common components of beach sand.
Aluminium Reactive metal, and does not
occur in the metallic state in nature
All of the earth's aluminum has combined with other elements to form compounds
Two of the most common compounds: alum
Example: potassium aluminum sulfate (KAl(SO4)2·12H2O), and aluminum oxide (Al2O3)
Bauxite Mainly aluminum oxide (Al2O3) Most important ore Bauxite production - processed first
into alumina, and then into aluminium by electrolysis
Used in cement, chemicals, face makeup, soda cans, dishwashers, siding for houses
They were formed by lateritization of various silicate rocks
Example: granite, gneiss, basalt, syenite, and shale
Calcium Soft grey alkaline earth metal A silvery metallic element that must be
extracted by electrolysis from a fused salt
Example: calcium chloride Once produced, it rapidly forms a grey-
white oxide and nitride coating when exposed to air
Calcium metal reacts with water, evolving hydrogen gas at a rate rapid enough to be noticeable, but not fast enough at room temperature to generate much heat
Calcium with Water Ca (s) + 2H2O (g) Ca(OH)2 (aq) + H2 (g) Under normal conditions calcium carbonate is
water insoluble When carbon dioxide is present carbonic acid is
formed, affecting calcium compounds. The reaction mechanism for carbon weathering is:
H2O + CO2 H2CO3 & CO32- + H2CO3 Ca(HCO3)2
And the overall reaction :CaCO3 (s) + CO2 (g) + 2H2O (l) Ca2+ (aq) + 2 HCO3- (aq)
The product is calcium hydrogen carbonate.
Sodium Occur as: Salt Amphibole Zeolite Forms a very important part of blood
plasma. Allows our bodies to maintain the
right blood chemistry and the correct amount of water in our blood.
Essential for normal functioning of our nervous system
Reaction of Sodium
It has two reaction: With water:2Na(s) + 2H2O → 2NaOH(aq) + H2(g)* form sodium hydroxide With air:
1. 2Na(s) + O2 (g) → 2Na2O2(s)2. 4Na(s) + O2 (g) → 2Na2O(s)* form sodium peroxide and sodium oxide
Potassium Great importance for soil health,
plant growth and animal nutrition. Occurs in:
1. Orthoclase (potassium feldspar): Common rock forming mineral
2. Granite3. Sylvite4. Carnallite
Potassium deficiency caused restricted growth, reduced flowering, lower yields and lower quality produce.
Reaction of Potassium
Simple two reaction: With water:
2K (s) + 2H2O (l) -> 2KOH (aq) + H2 (g)* form potassium hydroxide
With air:K(s) + O2(g) → KO2(s)*form potassium superoxide
Magnesium For the proper growth, formation
and function of our bones and muscles.
Control how our muscles contract. Essential in allowing your body to
control insulin levels in your blood.
Present in seawater: Mg2+ (second most abundant cation in seawater)
Reaction of Magnesium
With water vapor, form magnesium hydroxide and hydrogen gas:Mg (s) + 2H2O(g) →Mg(OH)2(aq) + H2(g)
With water:Mg (s) + 2H2O(g) -> Mg(OH)2(aq) + H2(g)* form magnesium hydroxide
With air:1. 2Mg(s) + O2 (g) → 2MgO(s)2. 3Mg(s) + N2 (g) → Mg3N2 (s)* form magnesium oxide and magnesium nitride
References http://
education.jlab.org/glossary/abund_ele.html
http://www.windows2universe.org/earth/geology/crust_elements.html
http://chemistry.about.com/od/elementfacts/a/silicon.htm
http://www.webelements.com/potassium/chemistry.html