Answer: 0.0257 moles of
and 0.0257 moles of 
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

moles of 
The balanced reaction for dissociation will be:
According to stoichiometry:
1 mole of
gives 1 mole of
and 1 mole of 
Thus there will be 0.0257 moles of
and 0.0257 moles of 
BaSO4 is the correct formula for barium (ll) sulfate
Answer:
a) nitrogen
b) nitrogen =5
Oxygen = 6
Fluorine =7
Explanation:
Usually, if we have two or more elements in a compound, the central atom in the compound is the atom having the least value of electro negativity.
If we consider fluorine, oxygen and nitrogen; nitrogen is the least electronegative of the trio hence it should be the central atom of the triatomic molecule.
The number of valence electrons on the valence shell of each atom is shown below;
nitrogen =5
Oxygen = 6
Fluorine =7