What are the empirical and molecular formulas of the compound

In summary, to solve for the empirical and molecular formulas of a compound that contains only carbon, hydrogen, and oxygen, you must first find the grams of carbon and hydrogen from the given masses of CO2 and H2O. Then, subtract this amount from the original mass to find the grams of oxygen. Next, calculate the moles of each element and use these values to find the empirical formula of the compound. Finally, divide the molecular mass by the empirical mass to find a value that, when multiplied by the empirical formula, gives the molecular formula of the compound.
  • #1
Kingthi
1
0
"A compound contains only carbon, hydrogen, and oxygen. Combustion of 10.68 mg of the compound yields 16.01 mg CO2 and 4.37 mg H2O. The molar mass of the compound is 176.1 g/mol. What are the empirical and molecular formulas of the compound."

I saw an earlier post but it wasn't solved yet. There were some good explanations but can I get a step by step guide to solving this, i just can't seem to get it

I have started off by finding the moles of CO2 and H2O but after that step i cannot find the next step. The answer to the problems are C3H4O3 and C6H8O6
 
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  • #2
You can work out how many moles of C and H are produced from the masses of the CO2 and H2O given, ignore the oxygen because you don't know how much came from the air.
You know how many moles of the substance there were so you can work out how many carbon and hydrogen it had.
You have the molecular mass so any difference between the amount of carbon and hydrogen you worked out must be oxygen.
 
  • #3
1) find the grams of C from CO2, find the grams of H from H2O

2) Original amount - grams of (C + H) = Grams of O

3) find the moles of C from CO2, H from H2O, O from molar mass of O

4) CxHyOz ... divide by the smallest amount of moles and manipulate your findings till you have a whole number which gives you your Empirical Formula

5) MW/EW = some value = Multiply your EF by this value.
 
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  • #4
i just worked it ... it works, have you solved it yet?
 

FAQ: What are the empirical and molecular formulas of the compound

What are the empirical and molecular formulas of the compound?

The empirical formula of a compound is the simplest whole number ratio of the elements present in the compound. This can be determined by analyzing the mass percent composition of the elements in the compound.

The molecular formula of a compound is the actual number of atoms of each element present in one molecule of the compound. It can be determined by comparing the empirical formula to the molar mass of the compound.

How do you calculate the empirical formula of a compound?

To calculate the empirical formula, you first need to determine the mass percent composition of each element in the compound. Then, convert the mass percent of each element to moles and divide by the smallest number of moles to get the simplest whole number ratio. This ratio represents the empirical formula of the compound.

What is the difference between empirical and molecular formulas?

The empirical formula is the simplest whole number ratio of the elements in a compound, while the molecular formula is the exact number of atoms of each element in one molecule of the compound. The molecular formula may be the same as the empirical formula or a multiple of it.

Can a compound have the same empirical and molecular formula?

Yes, a compound can have the same empirical and molecular formula. This means that the compound is made up of simple whole number ratios of elements in its molecule. For example, H2O has the same empirical and molecular formula.

How can I determine the molecular formula of a compound?

To determine the molecular formula of a compound, you need to know the empirical formula and the molar mass of the compound. Then, divide the molar mass by the empirical formula mass to find the number of times the empirical formula must be multiplied to get the molecular formula.

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