What is the molecular formula of the molecule that has an empirical formula of CH2 O and a molar

What is the molecular formula of the molecule that has an...

Key Concepts

Determining the Molecular Formula from the Empirical Formula and Molar Mass

To find the molecular formula from the empirical formula, you first calculate the mass of the empirical unit. Then, by dividing the compound's molar mass by this empirical mass, you obtain a scaling factor. Multiplying each subscript in the empirical formula by this factor gives the actual molecular formula.

Molar Mass

Molar mass is defined as the mass of one mole of a substance, calculated by summing the atomic masses of all atoms in the molecular formula. It is expressed in grams per mole (g/mol) and is essential for relating the measured mass of a compound to the number of molecules it contains.

Empirical Formula

The empirical formula represents the simplest whole?number ratio of the elements in a compound. It provides a simplified depiction of the relative number of atoms of each element present but does not necessarily show the actual number of atoms in a molecule.

Molecular Formula

The molecular formula shows the actual number of atoms of each element in a molecule. It is typically a whole?number multiple of the empirical formula and is determined using experimental data such as the compound's molar mass.

Transcript

00:01 Remember that the empirical formula has the lowest ratio of all the atoms in the formula, whereas the molecular formula is the actual formula.

00:11 So it's usually a multiple of the empirical formula.

00:17 So if we're given the empirical formula of c, h2o, and we're told that it has a molar mass of 120 .12 grams per mole, then what we want to do here is figure out each individual grams per mole for each element and just kind of add that up and that's going to give us kind of like an empirical version of this compound molar mass if you will so let's start carbon we know from the periodic table that there's 12 .01 grams per mole and that there's only one carbon present here.

01:37 Let's take hydrogen.

01:49 There's two hydrogens present here in the empirical formula, and we know that hydrogen has an atomic mass of 1 .01 grand per mole, which is going to give us 2 .02.

02:14 And then for oxygen, there's one oxygen present, and we know from the period of table, its atomic mass is 16 grams per mole.

02:37 If we add all this up, it's going to give us kind of like an empirical mass of 30 .03.

03:02 Grams per mole.

03:04 So simply to convert from this empirical formula and we want to know the molecular formula, we just kind of want to know, we're just going to divide the 120 .12 grams per mole that we know this compound has, divided by this 30 .03, and that's going to tell us the ratio of each number, or kind of like the multiple of each number that we have.

03:29 So we take that 120 .12 grams per mole, divided by 30 .03 grams per mole.

03:57 That's going to give us four...

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