# Organic Chemistry-Empirical formula problems

• ChemistryGuy1
In summary, an empirical formula in organic chemistry is the simplest whole number ratio of atoms in a molecule, which does not give the exact number of each type of atom present but rather their relative proportion. It can be determined experimentally by analyzing the mass or percent composition of each element, or calculated from the molecular formula by dividing each subscript by the greatest common factor. The main difference between the empirical and molecular formula is that the latter gives the exact number of each type of atom present and is usually a multiple of the former. However, in some cases, they can be the same, such as for small molecules like water, methane, and ammonia. To determine the molecular formula from the empirical formula, the molecular weight of the compound is needed.
ChemistryGuy1

## Homework Statement

1)After analyzing an organic substance ,it came to this: 29,752% Carbon;5,785%Hydrogen:26,446% Sulpur and 11,57% Sodium.It is also that known that between the Oxygen mass and Sodium mass ,in a mole of substance analyzed,it's a difference of 18 grams.Determinate the molecular formula of the substance.

2) Volume of 0,56 dm3 of a gas hydrocarbon weights in normal conditions 1,45 grams.Knowing that the atomic ratio of the elements of the hydrocarbons is C : H = 2 : 5 fiend the molecular formula of the hydrocarbons.
A)CH4 B)C2H6 C)C4H10

3) A probe from a organic substance whit the raw(brute) formula CnH2nO who contains 0,6 moles makes in oxidation 79,2 mini grams CO2.Determinate the molecular formula of the organic substance

How i do these problems?

## Homework Equations

It's the first semester and it's using basic formulas plus it will use the empirical formula to fiend the formula at the end i think

## The Attempt at a Solution

I don't know how to do it :/ i mean i may know how to begin a little but it may be wrong

Tell me what you don't understand and i shall translate it for you

1) To determine the molecular formula of the substance, we need to first calculate the empirical formula. This can be done by converting the percentages of each element into moles. Then, we need to find the lowest whole number ratio of these moles to get the empirical formula. The molecular formula can then be determined by multiplying the empirical formula by a whole number.

2) To determine the molecular formula of the hydrocarbon, we need to first calculate the molar mass of the gas. This can be done by using the ideal gas law and the given information about the volume and weight of the gas. Then, we need to find the ratio of carbon to hydrogen in the hydrocarbon. The molecular formula can then be determined by multiplying the empirical formula by a whole number.

3) To determine the molecular formula of the organic substance, we need to first calculate the molar mass of the substance by using the given information about the number of moles and the amount of CO2 produced. Then, we need to find the lowest whole number ratio of carbon, hydrogen, and oxygen in the substance. The molecular formula can then be determined by multiplying the empirical formula by a whole number.

## 1. What is an empirical formula in organic chemistry?

An empirical formula in organic chemistry represents the simplest whole number ratio of atoms in a molecule. It does not necessarily give the exact number of each type of atom present in a molecule, but it gives the relative proportion of atoms.

## 2. How is the empirical formula determined?

The empirical formula can be determined experimentally by analyzing the mass or percent composition of each element in a molecule. It can also be calculated from the molecular formula by dividing each subscript by the greatest common factor.

## 3. What is the difference between empirical and molecular formula?

The empirical formula represents the simplest whole number ratio of atoms in a molecule, while the molecular formula gives the exact number of each type of atom present in a molecule. The molecular formula is usually a multiple of the empirical formula.

## 4. Can the empirical formula and the molecular formula be the same?

Yes, the empirical formula and molecular formula can be the same if the molecule is already in its simplest form. This is usually the case for small molecules such as water (H2O), methane (CH4), and ammonia (NH3).

## 5. How can I use the empirical formula to determine the molecular formula?

To determine the molecular formula from the empirical formula, you will need to know the molecular weight of the compound. Divide the molecular weight by the empirical formula weight to find the multiple. Then, multiply each subscript in the empirical formula by this multiple to get the molecular formula.

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