methyl salicylate has a mass percent composition of 63.2% C, 31.6% O, and 5.26% H.The mass of one molecule of the compound is 2.53 x 10^-22.Determine the empirical formula and the molecular formula for methyl salicylate.
Take a 100 g sample and convert grams to moles.
63.2/12 = ??moles C
31.6/16 = ??moles O
5.26/1 = ??moles H.
Now find the ratio of these elements t one another with the smallest number being 1. The easy way to do that is to divide the smallest number by itself (which will automatically make that 1.000), then divide the other numbers by the same small number. Round to whole number unless the values are not close to whole numbers. IN this case, they are not so try multiplying all by 2, then 3, then 4, then 5, etc until all end up close to whole numbers. That will be the empirical formula. I ended up with C8H8O3.
The approximate molar mass is the mass of 1 molecule x 6.022E23.
Then molecular formula mass/empirical formula mass = n. Round n to a whole number and that will give you the molecular formula; i.e., (C8H8O3)n
To determine the empirical formula of methyl salicylate, we need to calculate the ratio of the elements present in the compound based on the given mass percent composition.
Let's assume we have 100g of methyl salicylate.
1. Convert the mass percentages to grams:
- Carbon (C): 63.2g (63.2% of 100g)
- Oxygen (O): 31.6g (31.6% of 100g)
- Hydrogen (H): 5.26g (5.26% of 100g)
2. Convert the grams of each element to moles:
- Carbon (C): 63.2g / 12.01 g/mol = 5.26 mol C
- Oxygen (O): 31.6g / 16.00 g/mol = 1.975 mol O
- Hydrogen (H): 5.26g / 1.01 g/mol = 5.20 mol H
3. Finally, divide each number of moles by the smallest number to get the simplest whole-number ratio:
- Carbon (C): 5.26 mol / 5.20 mol = 1
- Oxygen (O): 1.975 mol / 5.20 mol = 0.379
- Hydrogen (H): 5.20 mol / 5.20 mol = 1
Therefore, the empirical formula of methyl salicylate is CH2O (1 carbon, 2 hydrogen, 1 oxygen).
To determine the molecular formula of methyl salicylate, we need to compare the molar mass of the empirical formula to the given mass of one molecule.
4. Calculate the molar mass of the empirical formula:
- Carbon (C): 1 atom x 12.01 g/mol = 12.01 g/mol
- Hydrogen (H): 2 atoms x 1.01 g/mol = 2.02 g/mol
- Oxygen (O): 1 atom x 16.00 g/mol = 16.00 g/mol
Total molar mass of CH2O = 12.01 + 2.02 + 16.00 = 30.03 g/mol
5. Compare the molar mass of the empirical formula to the given mass of one molecule:
- Given mass of one molecule: 2.53 x 10^-22 g
- Multiply the molar mass (30.03 g/mol) by the number of empirical formula units in one molecule:
(2.53 x 10^-22 g) / (30.03 g/mol) = 8.42 x 10^-24 mol
- Multiply the number of empirical formula units from step 3 by the result from the previous step:
1 x (8.42 x 10^-24 mol) = 8.42 x 10^-24 mol
6. Finally, determine the molecular formula:
- The empirical formula (CH2O) multiplied by the number from step 5:
CH2O x (8.42 x 10^-24 mol) = C8H16O8
Therefore, the molecular formula of methyl salicylate is C8H16O8.
To determine the empirical formula and molecular formula for methyl salicylate, we need to first calculate the empirical formula using the given mass percent composition.
Step 1: Convert the mass percent composition to grams.
Given:
Mass percent of C = 63.2%
Mass percent of O = 31.6%
Mass percent of H = 5.26%
To convert the mass percent to grams, assume that we have a 100g sample.
Mass of C = (63.2/100) x 100g = 63.2g
Mass of O = (31.6/100) x 100g = 31.6g
Mass of H = (5.26/100) x 100g = 5.26g
Step 2: Calculate the number of moles of each element.
To calculate the number of moles, we need to divide the mass of each element by its molar mass.
Molar mass of C = 12.01 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of H = 1.01 g/mol
Number of moles of C = 63.2g / 12.01 g/mol = 5.268 mol
Number of moles of O = 31.6g / 16.00 g/mol = 1.975 mol
Number of moles of H = 5.26g / 1.01 g/mol = 5.204 mol
Step 3: Divide each number of moles by the smallest number of moles.
The empirical formula represents the simplest whole number ratio of elements in a compound. To find the empirical formula, divide each number of moles by the smallest number of moles.
For methyl salicylate, the smallest number of moles is 1.975 (from O).
Number of moles of C (rounded to the nearest whole number) = 5.268 / 1.975 ≈ 2.7
Number of moles of O (rounded to the nearest whole number) = 1.975 / 1.975 = 1
Number of moles of H (rounded to the nearest whole number) = 5.204 / 1.975 ≈ 2.6
Step 4: Write the empirical formula.
The empirical formula is written using the whole number ratio calculated in the previous step.
Empirical formula for methyl salicylate: C2.7O1H2.6
Step 5: Calculate the molecular formula.
To find the molecular formula, we need additional information - the mass of one molecule of the compound. Given that the mass of one molecule of methyl salicylate is 2.53 x 10^-22 g, we can compare the molar mass of the empirical formula with the molar mass of the molecular formula to find the ratio.
Molar mass of empirical formula = (2.7 x 12.01) + (1 x 16.00) + (2.6 x 1.01) = 60.0 g/mol (approximately)
Now, we calculate the ratio of the molar mass of the molecular formula to the molar mass of the empirical formula.
Ratio = (2.53 x 10^-22 g) / (60.0 g/mol)
By dividing the molecular mass by the empirical mass, we can find the number of empirical formula units per molecule.
Ratio (rounded to the nearest whole number) = (2.53 x 10^-22 g) / (60.0 g/mol) ≈ 4.2 x 10^-24
Finally, we multiply the subscripts of the empirical formula by the ratio to obtain the molecular formula:
Empirical formula: C2.7O1H2.6
Molecular formula: C11O4H10