a compound contains 63.15% Carbon, 5.30% hydrogen, 31.55% oxygen. Its molar mass is 152.14 g/mol. determine the empirical and molecular formula.
I get the empirical formula to be C8H803 is it right because it is not fitting the molecular formula because when i divide the molar mass given by the molar mass of empirical i do not get a whole natural number.
Well, well, well, looks like we've got a chemical mystery on our hands! Let's put on our detective hats and solve this case!
You're right in finding the empirical formula to be C8H8O3. However, it seems that the molar mass of the empirical formula (148.17 g/mol) doesn't quite match the given molar mass (152.14 g/mol). Fear not, my friend, we can certainly crack this code!
To find the molecular formula, we need to determine how many empirical formula units are present in one molecule. All we need is the ratio between the molar mass of the empirical formula and the molar mass given to us.
152.14 g/mol divided by 148.17 g/mol gives us around 1.027. Now, here's where things get a bit tricky. We want a whole number ratio, so we need to round off the 1.027 to the nearest whole number. In this case, the closest whole number is 1.
Therefore, the molecular formula ends up being simply C8H8O3. No need to worry about the decimal point here!
Remember, science isn't always as precise as we imagine. Sometimes we need to round off, just like when deciding how many cookies to eat. Always go for the closest whole number – it's always more satisfying that way!
To determine the empirical formula of a compound from percentage composition, you need to convert the percentages to moles.
First, assume you have 100 g of the compound.
Then, you can find the moles of each element in the compound using their respective molar masses.
The given percentages indicate that 63.15 g is carbon, 5.30 g is hydrogen, and 31.55 g is oxygen.
Next, determine the number of moles for each element:
Number of moles of carbon = mass of carbon / molar mass of carbon = 63.15 g / 12.01 g/mol = 5.257 moles
Number of moles of hydrogen = mass of hydrogen / molar mass of hydrogen = 5.30 g / 1.01 g/mol = 5.248 moles
Number of moles of oxygen = mass of oxygen / molar mass of oxygen = 31.55 g / 16.00 g/mol = 1.972 moles
Now, divide each number of moles by the smallest number of moles to obtain the simplest whole-number ratio. In this case, the smallest number of moles is 1.972:
Number of moles of carbon = 5.257 / 1.972 ≈ 2.67
Number of moles of hydrogen = 5.248 / 1.972 ≈ 2.66
Number of moles of oxygen = 1.972 / 1.972 = 1
Since we want to find a whole-number ratio, we can round the number of moles to the nearest whole number:
Number of moles of carbon ≈ 3
Number of moles of hydrogen ≈ 3
Number of moles of oxygen = 1
Therefore, the empirical formula of the compound is C3H3O.
To determine the molecular formula, you need to know the molar mass of the compound. In this case, the molar mass is given as 152.14 g/mol.
Calculate the empirical formula mass:
Empirical formula mass = (molar mass of carbon x number of carbon atoms) + (molar mass of hydrogen x number of hydrogen atoms) + (molar mass of oxygen x number of oxygen atoms)
Empirical formula mass = (12.01 g/mol x 3) + (1.01 g/mol x 3) + (16.00 g/mol x 1)
Empirical formula mass = 36.03 g/mol + 3.03 g/mol + 16.00 g/mol
Empirical formula mass = 55.06 g/mol
Next, divide the molar mass of the compound by the empirical formula mass to determine the number of empirical formula units in the molecule:
Molecular formula = molar mass of compound / empirical formula mass
Molecular formula = 152.14 g/mol / 55.06 g/mol
Molecular formula ≈ 2.766
Since dividing the molar mass by the empirical formula mass does not result in a whole number close to 1, it suggests that the empirical formula is not the same as the molecular formula.
Therefore, the empirical formula is C3H3O, but the molecular formula cannot be determined solely based on the given information. Further experimental data or additional information on the molecular structure is needed to determine the molecular formula.
To determine the empirical formula, we need to find the simplest whole-number ratio of atoms in the compound given the percentage composition.
Let's assume we have 100 grams of the compound. From the percentage composition, we can convert the masses of each element into moles:
- Carbon: (63.15 g / 12.01 g/mol) = 5.259 mol
- Hydrogen: (5.30 g / 1.01 g/mol) = 5.248 mol
- Oxygen: (31.55 g / 16.00 g/mol) = 1.972 mol
Next, we divide each of the mole values by the smallest mole value to obtain the ratio:
- C: 5.259 mol / 1.972 mol ≈ 2.667
- H: 5.248 mol / 1.972 mol ≈ 2.659
- O: 1.972 mol / 1.972 mol = 1
Since we want whole-number ratios, we multiply each value by 3 to get the empirical formula:
- C: 2.667 * 3 ≈ 8
- H: 2.659 * 3 ≈ 8
- O: 1 * 3 = 3
So, the empirical formula is C8H8O3.
Now, to determine the molecular formula, we need the molar mass of the empirical formula. The empirical formula C8H8O3 has a molar mass of:
- (8 * 12.01 g/mol) + (8 * 1.01 g/mol) + (3 * 16.00 g/mol) = 152.27 g/mol
Divide the given molar mass of the compound (152.14 g/mol) by the molar mass of the empirical formula (152.27 g/mol) to find the whole-number ratio:
- 152.14 g/mol / 152.27 g/mol ≈ 1
Since the ratio is approximately 1, the empirical formula is also the molecular formula. Therefore, the molecular formula is C8H8O3.