Barium nitrate and methane (CH4) are both soluble. They both will dissolve in water, however, barium nitrate will dissociate becoming barium 2+ ions and nitrate becoming NO3 1- ions. All nitrates are soluble and dissociate. CH4 is a weak base and does dissolves but doesn't dissociate. So in solubility terms.... they are both equally soluble just one happens to dissociate into its cations and anions. Hope this helps!
The gravitational force between the objects depends on the mass of the objects and the distance between them.
The mineral is Iron Sulphide. It is not a mixture, but a compound. A mixture is when two substances are together, but not chemically bonded. For example, if I add food colouring to water, I have made a mixture because the food colouring has not chemically bonded to the water. If I react Iron with Suphur, the resulting substance is a compound. The resulting mineral will not burn or be magnetic because the compound has different properties to the elements themselves. For example, chlorine gas is toxic and sodium reacts violently with water, but sodium chloride is table salt, nor toxic nor explosive.
Hope this helps
Molar mass HCl = 36.5 g/mol
number of moles:
mass of solute / molar mass:
9.63 / 36.5 => 0.263 moles
Volume = 1.5 L
M = n / V
M = 0.263 / 1.5
M = 0.1753 mol/L
espero ter ajudado!