What is the limiting reactant when 44.7 g of CuO are exposed to 2.84 g of H2 according to the equation
CuO(s) + H2(g) −→ Cu(s) + H2O(g) ? 1. Neither is limiting.
2. CuO
3. H2
4. Unable to determine.

the answer is false because not all countries have geysers under their crust. for example, iceland uses geothermal energy because it is available every in their country.  

it is stable as it is in group 0 which have full outer shells of electrons

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally