What is the empirical formula of this compound thanks?

In summary: For example, if you have 50% of something, then the rest obviously has to be composed of something else.What is the empirical formula of a compound with 16.1% Na, 4.2% C, 16.8% O, and 62.9% H2O?In summary, the given hydrated substance has a composition of 16.1% Na, 4.2% C, 16.8% O, and 62.9% H2O. To find the empirical formula, one should convert the percentages to grams, then to moles, and finally divide by the smallest mole quantity. The resulting numbers should be multiplied by a common factor to obtain the empirical formula
  • #1
juicy--
1
0
A hydrated substance was found to have the following percentages composition:

Na = 16.1%
C = 4.2%
O = 16.8%
H2O = 62.9%


What is the empirical formula of this compound?

------------

im really confused and don't know where to start so if someone could help itd be very much appreciated!

thank you :)
 
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  • #2
There's a post further down on the board that addresses a problem like this. I'll copy and paste MichealXY's poem that should help:

Percent to mass,
Mass to mole,
Divide by small,
Multiply 'til whole.

Assume 100g of compound. Change % to g. Divide these masses by their molar masses to get moles. Divide each mole amount by the smallest mole quantity of the group. You'll get numbers that are either close to a whole number or close to half (such as 1.5, 2.5, etc.) multiply all of the numbers by a common factor until they are all whole numbers, and this will be the empirical formula.
 
  • #3
Yes what juicy said is correct. This is obviously going to be a hydrate so it might be a little tricky figuring it out for that part. Make sure that once you "think" you have the right answer, that you check it to make sure the percentages check out correctly.
 

1. What is the empirical formula of a compound?

The empirical formula of a compound is the simplest whole number ratio of atoms present in a molecule.

2. How is the empirical formula determined?

The empirical formula is determined by analyzing the mass percentage of each element in a compound and converting it into moles. The resulting mole ratios are then simplified to their lowest whole number ratio.

3. Can the empirical formula be the same as the molecular formula?

Yes, the empirical formula can be the same as the molecular formula if the compound is a simple molecule with no subscripts. However, in most cases, the molecular formula will be a multiple of the empirical formula.

4. What is the difference between empirical and molecular formula?

The empirical formula only shows the relative ratios of atoms in a compound, while the molecular formula gives the exact number of atoms of each element present in a molecule.

5. Can the empirical formula of a compound change?

Yes, the empirical formula can change if the ratio of atoms in a compound changes due to different experimental conditions or if the compound can exist in different isomeric forms with different ratios of atoms.

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