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# Can you determine the molecular formula of a substance from its percent composition?

###### Wiki User

Not completely. The empirical formula of a substance can be determined from its percent composition, but a determination of molecular weight is needed to decide which multiple of the empirical formula represents the molecular formula.

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## Related Questions

### It is possible to determine the molecular formula of a substance from its percentage composition?

From the percentage composition only, an empirical formula can be derived, but a proper molecular formula can only be assured by adding some information about the molecular weight of the substance concerned.

### What does compounds molecular formula tells what?

Molecular formula of a chemical substance is representative for the composition of this chemical substance.

### Can you determine the molecular formula of a substance from its percentage composition?

Yes, if you have some additional information, such as the molecular weight. For instance, the molecules C2H4 and C4H8 have exactly the same percent composition, but they are very different molecules. So you need some other information to tell them apart than the percent composition.Answer ExpandedThis is kind of a trick question. By knowing the percent composition, you would easily be able to determine its empirical formula, but molecular formula is a bit different. The molecular formula is the actual number of atoms in a molecule, so in order to find the specific molecular formula of a substance, you would also need to know how many grams there is of that substance.(This explains the difference between C2H4 and C4H8)

### Explain why the percent composition of certain compounds are not sufficient to determine the compounds molecular formulas?

Because unlike the empirical formula, the molecular formula does not have to be the simplest ratio.If by chance you are given the percent composition of the elements in a substance, you could calculate the empirical formula and then the empirical formula's mass. However, the molecular formula equation is molecular formula= (empirical formula)n, where n is the mass of the molecular formula divided by the mass of the empirical formula. You would, therefore, need to know the mass belonging to the molecular formula, which you are not given.

### Why is sugar a pure substance?

Sugar is a pure substance because it has a definite composition. Its molecular formula is C12H22O11.

### What tells you the number and types of atoms within a substance?

You can determine the chemical formula of this substance and consequently the elemental composition.

### What does a compound formula tell you?

A compound formula, or molecular formula, tells you about the chemical composition of the substance in terms of the number of atoms of that element that are present. From there, the empirical formula may also be derived by simplifying the molecular formula, as well as its structural formula.

### What is the molecular formula of a substance that has an empirical formula of C2H5 and a molecular mass of 58 grams per mole?

The molecular formula of a substance that has an empirical formula of C2H5 and a molecular mass of 58 grams per mole is C4H10 Butane.

### Formula of Gases?

The chemical formula of gases is dependent on their molecular composition.

### What do you need to calculate the percentage composition of a substance?

The molecular formula of the compound can be calculated from the composition of element in a compound. The next steps are involved in the calculation of percentage of every element in a compound.

### Derivation of formula?

Formula regards the composition of a substance. In Chemistry molecular formula is derived by the composing elements and their atomic quantities. For example the chemical formula of water (H2O) is two hydrogen and single oxygen.

### Which formula represents a molecular compound?

A molecular formula contain indication about the chemical composition of the compound but no information about the structure.

### What is the molecular formula based upon?

The formula is based on the chemical composition of the molecule.

### What are the steps to determine molecular formula?

There are 4 step to determine molecular formula, which are given bellow Step:1:- Find empirical formula Step:2:- Find empirical formula mass Step:3:- Find n n=molecular mass/empirical formula mass Step:4:- now find molecular formula to find molecular formula molecular formula(empirical formula)n

### How do you get from emperical formula to molecular formula?

By determining the molecular mass, then dividing the molecular mass by the formula mass of the empirical formula to determine by what integer the subscripts in the empirical formula must be multiplied to produce the molecular formula with the experimentally determined molecular mass.

### How is a molecular formula determined?

The molecular formula is the number and type of atoms that are present in a single molecule of a substance.

### Composition of Hydrogen Peroxide?

The molecular formula of this compound is H2O2

### Chemical composition of TNT?

Trinitrotolune. The molecular formula is C7H5N3O6.

### Define emperical formula and molecular formula?

Molecular formula is the actual representation of the constitution of the substancewhile Empirical formula is the simplest representation of the molecular formula.Molecular formula= Empirical formula*n(where n= Molecular weight/Empirical formula weight)Example :-EtheneMolecular formula =C2H4Empirical formula=CH2here CH2 is the simplest representation of molecular formula of Ethene.

### What does a molecular formula look like?

In chemistry a molecular formula is used to illustrate the elemental composition and atomic quantities of a given molecular substance. A molecular formula is in the format of an elements symbol followed by a subscript of the # of atoms of each. For example water (chemically also known as dihydrogen monoxide) is H20 with the H and 2 symbolizing 2 atoms of hydrogen and a single oxygen.

### How can you find the molecular formula of a compound when its percentage composition is given?

You have to find its empirical formula using the percentage composition. When you have done that, work out the relative molecular mass (Mr) of the empirical formula. This should be a multiple of the compound's Mr, so you multiply the amount of each atom in the empirical formula by this number, which gives you the final molecular formula.

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