Which of the following is a correct formula unit of an ionic compound? (3 points) Al2O3
Ca2O
MgOH
NaCl2

#Divide given mass with their molar masses.

C=48.38÷12.01= 4.03mols

H= 6.74÷1.0079= 6.69mols

O= 53.5÷16.00= 3.34mols

#Divide the moles with the lowest mole.

C = 4.03÷3.34 = 1.21

H = 6.69÷3.34 = 2.00

O = 3.34÷3.34 = 1

∴Emperical Formula = CH₂O

#Molar mass of CH₂O = 12.01 + (1.0079 x 2) + 16.00 = 30.02 g/mol

#Divide both moler masses: 180.15g/mol÷30.02g/mol = 6

#Multiply the answer with the Emperical formula to get the Molecular formula: 6 x (CH₂O) = C₆H₁₂O₆

Empirical Formula: CH₂OMolecular Formula: C₆H₁₂O₆

Explanation:

Firstly, you have to divide the three masses of the elements with their respective molar mass to find their moles.  After you've found the moles use the lowest mole to divide the moles of each element again to find your empirical formula. Then you calculate the molar mass of the empirical formula and divide the molar mass with the given molar mass of  finally, multiply the answer with the empirical formula.