Answer: B. Ca2+ + 2e- ---------> Ca
Explanation:
Reduction involves the gaining of electrons as well as a decrease in the oxidation state of the atom or ion.
In this case; Ca2+ gains two electrons and the oxidation state is reduced from +2 to 0.
Ca2+ + 2e- ---------> Ca
Explanation:
Given parameters:
Dimension = 8.5in²
we are to convert from in² to cm²
in² = in x in
cm² = cm x cm
1 in = 2.54cm
Using dimensional analysis;
8.5in² x 
= 54.84cm²
We solved this problem using dimensional analysis where we multiplied the unit with 1.
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Copper oxidizes in moist air
2Cu + CO₂ + O₂ + H₂O = (CuOH)₂CO₃
copper reacts with concentrated acids, for example, with nitric acid
Cu + 4HNO₃ = Cu(NO₃)₂ + 2NO₂ + 2H₂O
copper reacts with chlorine
Cu + Cl₂ = CuCl₂
copper reacts with oxygen when heated
2Cu + O₂ = 2CuO
The Group 3A metals have three valence electrons in their highest-energy orbitals (ns2p1). They have higher ionization energies than the Group 1A and 2A elements, and are ionized to form a 3+ charges. The Group 3A metals are silvery in appearance, and like all metals are good conductors of electricity.
Coal falls under Graphite