An 85.00 g sample of an unknown compound contains 24.26 g molybdenum, 24.33 g sulfur, and the rest is oxygen. How many moles of molybdenum are present in the compound

A) 0.253 mol B) 0.7603 mol C) 2.276 mol D) MoS₃O₉ or Mo(SO₃)₃ E) molybdenum(VI) sulfite

Explanation:

For all the Mole problems you want to find divide grams of the element in compound by the molar mass of the element.

24.26 g Mo / 95.95 g = 0.2528

24.33 g S / 32.06 g = 0.7589 mol S

36.41 g O / 16 g = 2.276 mol O

S /  Mo =  0.7587 mol  / 0.2529 mol  =  3/ 1

O / Mo =  2.276 mol  / 0.2529 mol  =  9/ 1

The empirical formula of the compound is MoS₃O₉ or Mo(SO₃)₃.

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l