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How does one determine the molecular formula from the empirical formula?
Wiki User
∙ 2014-01-31 14:17:16
By first determining the approximate molecular mass of the compound in question, usually by measurements of osmotic pressure, freezing point depression, or some other colligative property that depends on the number of molecules present. The approximate molecular mass of the substance in question is then calculated from the colligative property measurements, and this value is then divided by gram molecular mass corresponding to the empirical formula. The nearest integer to the resulting quotient is then applied as a factor by which to multiply each subscript of the empirical formula to yield the molecular formula.
Wiki User
∙ 2014-01-31 14:17:16
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What is the empirical formula for potassium nitrate?
The empirical formula for potassium nitrate is the same as the molecular formula, KNO3, because the molecular formula shows only one atom each of potassium and nitrogen.
Is the number of atoms in a molecular formula always greater than a empirical?
No. A molecular formula can be the same as the empirical formula, such as CH4 (methane), because the two component atoms exist in a ratio that cannot be mathematically further broken down - one carbon to four hydrogens. In this case the molecular formula (the actual number of atoms per molecule), and the empirical formula (the simplest ratio of those numbers) is identical. On the other hand, ethane, C2H6 - two carbons to 6 hydrogens - has a molecular formula of C2H6 and a empirical formula of CH3, the ratio of 2 to 6 reduced to its simplest whole number form. Sooooooooooo, the molecular formula will always be equal to or greater than the empirical formula, and the empirical formula will always be equal to or less than the molecular formula. In other words (as if that wasn't enough), the molecular formula will never be less than the empirical formula and the empirical formula will never be greater than the molecular formula, but THE TWO CAN BE EQUAL. Whew!!! Ray
When are the empirical and molecular formulas the same?
If one of the atoms is already at its smallest amount. i.e. CH4 would be the same for both, while C2H8 would also have an empirical formula of CH4 though. H2O --> H2O etc.
What is the difference between the empirical and chemical formulas?
In an empirical formula, at least one of the element symbols must have a subscript (possibly including the implicit subscript "1" that is presumed when there is no explicit subscript) that is a prime number. The subscripts in a chemical formula must correspond to the actual number of atoms of each element present in a molecule or formula unit of the compound and therefore may be any integral multiple of the subscripts in the empirical unit. For example, the empirical formula of both acetylene (also called "ethyne") and benzene is CH, but the chemical formulas are C2H2 for acetylene and C6H6 for benzene. The empirical formula uses as subscripts the lowest whole number ratio of atoms combined in the substance. Many ionic substances do not have a molecular formula because they form a crystal lattice and not individual molecules. Molecular compounds may have both. The molecular formula shows the actual number of combined atoms in a single molecule.
What is the empirical formula of the compound C5h15O10?
The requirements for an empirical formula are that it give the correct ratios between all pairs of atoms in the actual molecule and have subscripts (including the value 1 implied by lack of an explicit subscript) with the lowest possible values to achieve all the correct ratios. To meet the latter condition, either one subscript must be one or the two smallest subscripts must be distinct prime number. The formula of the compound given has only one prime number subscript, 5. If all subscripts in the molecular formula are divided by the same number to yield an integral quotient, the resulting formula will still be empirically correct. In the given molecular formula, all the subscripts are integrally divisible by 5. Therefore, the empirical formula is CH3O2.
How dos one determine the molecular formula from the empirical formula?
molar mass/ empirical formula mass
How do you calculate Molecular formula from empirical formulaWhat could you do with that information to determine that the empirical and molecular formulas are related to one another by a factor of 6?
In order to find molecular formula from empirical formula, one needs to know the molar mass of the molecular formula. Then you simply divide the molar mass of the molecular formula by the molar mass of the empirical formula to find out how many empirical formulae are in the molecular formula. Then you multiply the subscripts in the empirical formula by that number.
How does one determine a molecular formula from the empirical form?
molar mass of unknown/molar mass of empirial = # of empirical units in the molecular formula. Example: empirical formula is CH2O with a molar mass of 30. If the molar mass of the unknown is 180, then 180/30 = 6 and molecular formula will be C6H12O6
What is the difference between a molecular formula and an empirical formula?
An empirical formula is one that shows the lowest whole number ratio of the elements present. The molecular formula shows the composition of the molecules. An example is phosphorus pentoxide, P2O5 empirical formula, P4O10 molecular formula.
How does one determine a molecule formula from the empirical formula?
The density or some other information must be given that allow you to find the molar mass. Calculate the empirical formula mass. Divide molar mass by empirical formula mass. This answer is multiplied by all subscripts of the empirical formula to get the molecular formula.
What other information is required to know whether a formula is both empirical and molecular?
Find the mass of the substance and divide it by the mass of the substance defined by the empirical formula. If you get 1, then the empirical formula is also the molecular one.
Can one substance have same empirical and molecular formula?
Yes it can be
What is the empirical formula for potassium nitrate?
The empirical formula for potassium nitrate is the same as the molecular formula, KNO3, because the molecular formula shows only one atom each of potassium and nitrogen.
What molecular formulas are an empirical formula?
Any molecular formula where the subscripts do not have a common factor that can divide them all. For example: CH4 (methane) is a molecular formula that is also an empirical formula because there is no number (other then one) that can divide both the 4 and the 1. Take ethane as another example. It hasn't the empirical formula which is similar to the molecular formula.
What molecular formulas are also an empirical formula?
Any molecular formula where the subscripts do not have a common factor that can divide them all. For example: CH4 (methane) is a molecular formula that is also an empirical formula because there is no number (other then one) that can divide both the 4 and the 1. Take ethane as another example. It hasn't the empirical formula which is similar to the molecular formula.
What do empirical formulas determine?
Empirical formulas determine the ratio of atoms of different elements within a chemical compound and can be derived by dividing the number of each element's atoms by their greatest common factor. They do not necessarily describe the full chemical makeup of a molecule. For example, benzene has the formula C6H6 but its empirical formula is simply CH because there is one hydrogen atom for every carbon atom. Glucose has the molecular formula of C6H12O6; its empirical formula is CH2O. Because the molecular formula for water, H2O, cannot be further simplified (empirical formulas have only whole numbers) H20 is also its empirical formula.
What is the difference between empirical and molecular formula?
An empirical formula is one that shows the lowest whole number ratio of the elements present. The molecular formula shows the composition of the molecules. An example is phosphorus pentoxide, P2O5 empirical formula, P4O10 molecular formula.
