Practice ECAT Chemistry questions with answers and explanations.
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Four oxygens contribute -8 total.
Sulfur must be +6 so the ion total is -2.
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Potassium is +1 and four oxygens total -8.
Manganese must be +7 for a neutral compound.
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Use E°cell=E°cathode-E°anode.
0.80-(-0.40)=1.20 V.
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Oxygen is the most abundant element in Earth's crust by mass.
It occurs mainly in oxides and silicate minerals.
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Aluminum is the most abundant crustal metal.
It is commonly found in aluminosilicate minerals and bauxite.
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Alkali metals have one valence electron.
They usually lose it to form +1 ions.
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Group 2 metals have two valence electrons.
They commonly lose both and form +2 ions.
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Filled valence shells are especially stable.
Noble gases therefore have little tendency to gain or lose electrons.
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Fluorine has very high electronegativity and a weak F-F bond.
It is the strongest elemental oxidizing halogen.
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Allotropes differ in atomic arrangement and properties.
Diamond and graphite are carbon allotropes.
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PH=-log(1×10^-3).
The result is 3.
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Graphite has delocalized electrons within its layers.
These electrons allow electrical conduction.
