Explanation:
Note: Molar masses of elements can be found online or in the periodic table.
Moles of Magnesium
= 3.60g / (24.3g/mol) = 0.148mol.
Moles of Chlorine
= 10.65g / (35.45g/mol) = 0.300mol.
Mole ratio of Magnesium to Chlorine
= 0.148mol : 0.300mol = 1 : 2.
Hence we have the empirical formula MgCl2.
Moles of Lithium
= 9.1g / (6.94g/mol) = 1.311mol.
Moles of Oxygen
= 10.4g / (16g/mol) = 0.650mol.
Moles ratio of Lithium to Oxygen
= 1.311mol : 0.650mol = 2 : 1.
Hence we have the empirical formula Li2O.
When we have this balanced equation for a reaction:
Fe(OH)2(s) ↔ Fe+2 + 2OH-
when Fe(OH)2 give 1 mole of Fe+2 & 2 mol of OH-
so we can assume [Fe+2] = X and [OH-] = 2 X
when Ksp = [Fe+2][OH-]^2
and have Ksp = 4.87x10^-17
[Fe+2]= X
[OH-] = 2X
so by substitution
4.87x10^-17 = X*(2X)^2
∴X^3 = 4.8x10^-17 / 4
∴the molar solubility X = 2.3x10^-6 M
Argon is a suitable choice for light bulbs because it's inert. Compared to a reactive gas like oxygen, the metal filimant would burn up in a reactive enviroment, which is why a noble gas is used.
