Empirical and Molecular Forumla calculation

In summary, the conversation discusses the composition of reductic acid and tasks related to determining its empirical and molecular formulas, as well as calculating the mass of one molecule of the compound. The empirical formula is determined to be C5H6O3, and to find the molecular formula, the number of carbon atoms in 1.23 g of the compound is compared to the given number of carbon atoms. Avogadro's number is used to calculate the mass of one molecule of reductic acid.
  • #1
Oblivion77
113
0

Homework Statement



Reductic acid contains 52.63% carbon, 5.30% hydrogen and 42.07% oxygen by mass.
a) Determine the empirical formula of reductic acid

b) If 1.23 g of reductic acid contains 3.25x10^22 atoms of carbon, what is the molecular formula of reductic acid ?

c) Calculate the mass of one molecule of reductic acid.


Homework Equations



-

The Attempt at a Solution



I already found that the empirical formula and found that to be C5H6O3. But I can't seem to get the other parts. Thanks for the help.
 
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  • #2
Use the molecular mass of the empirical formula to find the number of carbon atoms that there would be in 1.23 g and then compare this to the actual number of carbons given in the problem

e.g.

1.23 g ( moles / g = MW of C5H6O3 ) = moles of C5H6O3

convert this to atoms of C5H6O3 and then this to atoms of Carbon = x

3.25 X 10 ^ 22 atoms of carbon / x = the number factor to multiply your empirical formula to find the molecular formula.




For the next part simply use Avogadro's number.
 
  • #3


First, let's review the definitions of empirical and molecular formulas. An empirical formula is the simplest whole number ratio of atoms in a compound, while a molecular formula gives the exact number of each type of atom in a molecule. To determine the molecular formula, we need to know the molar mass of the compound.

a) To find the empirical formula, we can assume a 100 g sample of reductic acid, which would give us 52.63 g of carbon, 5.30 g of hydrogen, and 42.07 g of oxygen. We then need to convert these masses to moles by dividing by the molar masses of each element:

52.63 g C x (1 mol C/12.01 g C) = 4.38 mol C
5.30 g H x (1 mol H/1.01 g H) = 5.25 mol H
42.07 g O x (1 mol O/16.00 g O) = 2.63 mol O

We can then find the simplest whole number ratio by dividing each of these values by the smallest number of moles, which in this case is 2.63 mol O. This gives us an empirical formula of C2H2O.

b) To find the molecular formula, we need to know the molar mass of reductic acid. To do this, we can use the molar mass of the empirical formula (C2H2O) and compare it to the molar mass of the actual compound, which is given by the problem.

Molar mass of C2H2O = (2 x 12.01 g/mol) + (2 x 1.01 g/mol) + (1 x 16.00 g/mol) = 42.04 g/mol

We can then calculate the molar mass of the actual compound using the given percentages:

(52.63 g C/0.5263) + (5.30 g H/0.0530) + (42.07 g O/0.4207) = 100 g/mol

This means that the actual molar mass is approximately 100 g/mol.

Now, we can use the given information to set up a proportion to find the ratio of the actual molar mass to the molar mass of the empirical formula:

100 g/mol : 42.04 g/mol =
 

1. What is the difference between empirical and molecular formulas?

Empirical formulas show the simplest whole number ratio of atoms in a compound, while molecular formulas show the actual number of atoms in a compound.

2. How do you calculate the empirical formula of a compound?

To calculate the empirical formula, you need the mass or percent composition of each element in the compound. Then, you convert the mass or percent composition to moles, divide each value by the smallest number of moles, and use those values as subscripts in the empirical formula.

3. What is the purpose of calculating empirical and molecular formulas?

Calculating empirical and molecular formulas allows us to determine the chemical composition and structure of a compound. This information is important in understanding the properties and behavior of the compound.

4. Can a compound have the same empirical and molecular formula?

Yes, a compound can have the same empirical and molecular formula. This occurs when the compound has a simple structure with no subscripts that can be reduced.

5. Are empirical and molecular formulas the same for ionic and covalent compounds?

No, empirical and molecular formulas can be different for ionic and covalent compounds. In ionic compounds, the empirical formula represents the ratio of ions, while the molecular formula represents the actual number of ions in a molecule.

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