When 0.49 g of a molecular compound was dissolved in 20.00 g of cyclohexane, the freezing point of the solution was lowered by 3.9 0C. Determine the molecular mass of this compound.

The molecular mass of this compound is 131 g/mol

Explanation:

Depression in freezing point:

where,

= depression in freezing point  =

= freezing point constant  =

m = molality

i = Van't Hoff factor = 1 (for non-electrolyte)

= mass of solute = 0.49 g

= mass of solvent (cyclohexane) = 20.00 g

= molar mass of solute = ?

Now put all the given values in the above formula, we get:

Therefore, the molar mass of solute is 131 g/mol

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.