Skip to main content
Ch.3 - Chemical Reactions and Reaction Stoichiometry
Chapter 3, Problem 52b

What is the molecular formula of each of the following compounds? (b) empirical formula C2H4O, molar mass = 88.0 g/mol

Verified step by step guidance
1
1. First, calculate the molar mass of the empirical formula, C<sub>2</sub>H<sub>4</sub>O. The molar mass of carbon (C) is approximately 12.01 g/mol, hydrogen (H) is approximately 1.01 g/mol, and oxygen (O) is approximately 16.00 g/mol. Multiply each of these by the number of each atom in the empirical formula and add them together.
2. Once you have the molar mass of the empirical formula, divide the given molar mass of the compound (88.0 g/mol) by the molar mass of the empirical formula. This will give you a ratio.
3. Round this ratio to the nearest whole number. This number represents the number of empirical formula units per molecule of the compound.
4. Multiply the subscripts in the empirical formula by this ratio to get the molecular formula. This is the actual number of atoms of each element in a molecule of the compound.
5. The result is the molecular formula of the compound.

Verified Solution

Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Empirical Formula

The empirical formula represents the simplest whole-number ratio of atoms in a compound. For example, the empirical formula C2H4O indicates that for every two carbon atoms, there are four hydrogen atoms and one oxygen atom. It does not provide information about the actual number of atoms in a molecule, which can be determined by the molecular formula.
Recommended video:
Guided course
02:26
Empirical vs Molecular Formula

Molecular Formula

The molecular formula gives the actual number of each type of atom in a molecule of a compound. It is derived from the empirical formula by multiplying the subscripts by a whole number, known as the molecular weight factor. In this case, the molecular formula can be determined by comparing the molar mass of the compound to the molar mass of the empirical formula.
Recommended video:
Guided course
02:08
Determining Molecular Formulas

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in the molecular formula. For the compound with an empirical formula of C2H4O and a molar mass of 88.0 g/mol, this value is crucial for determining the molecular formula by comparing it to the molar mass of the empirical formula.
Recommended video:
Guided course
02:11
Molar Mass Concept