Answer:
d. 97.60 g
Explanation:
Given parameters:
Number of moles of formaldehyde = 3.25moles
 Ratio:
         C        H        O
         1         2        1
Unknown:
Mass of this sample  = ?
Solution:
The empirical formula of a compound is its simplest formula. It is the simplest whole number ratio of the atoms in a given substance.
The molecular formula is the actual formula of the compound.
 Since the molecular and empirical formula are the same here, the formula of the compound is;
          CH₂O
To find the mass of the formaldehyde, use the expression below;
    Mass  = number of moles x molar mass
       molar mass of CH₂O = 12 + 2(1) + 16  = 30g/mol
   Mass  = 3.25 x 30  = 97.5g
