An orgonic compound on analysis is found to contain C=18.6% , H=1.55% , Cl=55.04% , and O=24.8%.Calculate its molecular formula?
Your School SUBJECT seems to be CHEMISTRY.
Let me point out that the total adds up to 99.99; it should add to 100 but that probably won't make any difference in the answer.
Take 100 g sample which gives you
18.6 g C
1.55 g H
55.04 g Cl
24.8 g O
Convert to mols and I will estimate; you should recalculate each.
18.6/12 = about 1.6 C
1.55/1 = 1.55 H
55.04/35.5 = about 1.5
24.8/16 = 1.5
Now find the ratio of the elements to one another with the smallest being 1.00. The easy way to do that is to divide the smallest number by itself (thereby assuring it to be 1.00), then divide the other numbers by the same small number.
So the empirical formula is CHClO. Withe the information given the molecular formula cannot be calculated.
To calculate the molecular formula of the organic compound, we need to determine the empirical formula first. The empirical formula gives us the simplest ratio of atoms present in the compound.
1. Convert the percentage composition to grams:
If we assume we have 100g of the compound, we can convert the percentages to grams:
- Carbon (C): 18.6g
- Hydrogen (H): 1.55g
- Chlorine (Cl): 55.04g
- Oxygen (O): 24.8g
2. Convert grams to moles:
To convert the grams to moles, we need to divide the mass of each element by its molar mass. The molar mass is found by looking up the atomic masses of the elements in the periodic table.
- Carbon (C): 18.6g / 12.01 g/mol = 1.55 moles
- Hydrogen (H): 1.55g / 1.008 g/mol = 1.54 moles
- Chlorine (Cl): 55.04g / 35.45 g/mol = 1.553 moles
- Oxygen (O): 24.8g / 16.00 g/mol = 1.55 moles
3. Determine the empirical formula:
The empirical formula gives us the simplest whole-number ratio of the elements. To find it, we divide the moles of each element by the smallest number of moles obtained. In this case, the smallest number of moles is 1.54 (from hydrogen), so we divide all the moles by 1.54:
- Carbon (C): 1.55 moles / 1.54 moles = 1
- Hydrogen (H): 1.54 moles / 1.54 moles = 1
- Chlorine (Cl): 1.553 moles / 1.54 moles = 1.01
- Oxygen (O): 1.55 moles / 1.54 moles = 1
Therefore, the empirical formula is CHClO.
4. Calculate the molar mass of the empirical formula:
The molar mass of CHClO can be calculated by summing the molar masses of each element in the formula. Using the atomic masses from the periodic table:
- Carbon (C) = 12.01 g/mol
- Hydrogen (H) = 1.008 g/mol
- Chlorine (Cl) = 35.45 g/mol
- Oxygen (O) = 16.00 g/mol
So, the molar mass of CHClO is: (12.01 g/mol) + (1.008 g/mol) + (35.45 g/mol) + (16.00 g/mol) = 64.48 g/mol
5. Calculate the empirical formula mass:
The empirical formula mass is the sum of the atomic masses in the empirical formula. In this case, it is:
(1 x 12.01 g/mol) + (1 x 1.008 g/mol) + (1.01 x 35.45 g/mol) + (1 x 16.00 g/mol) = 64.49 g/mol
6. Determine the ratio between the molar mass and the empirical formula mass:
To find the ratio, divide the molar mass by the empirical formula mass:
64.48 g/mol / 64.49 g/mol ≈ 1
The ratio is approximately 1, which means that the molecular formula is the same as the empirical formula. Therefore, the molecular formula of the compound is CHClO.