Question

Calculate the empirical foula for a compound with the following mass percentage composition: 18.59% O, 37.25% S, 44.16% F.|

AOSF2
B. O2SaFg
C, 0823
> ,02S8aF4
£, OSF4

Answer 1

To find the empirical formula for a compound from its mass percentage composition, convert the percentages to moles using atomic mass, then divide by the smallest mole value to find the simplest whole number ratio. In this case, the empirical formula is OSF2.

Step-by-step explanation:

The empirical formula for a compound represents the simplest whole number ratio of the elements within that compound. To calculate it based on the mass percentage composition, follow these steps:

1. Assume a 100 g sample, which turns the percentages directly into mass for easier calculations.
2. Convert the masses into moles by dividing by the atomic mass of each element: O (16.00 g/mol), S (32.07 g/mol), F (19.00 g/mol).
3. Divide all the mole values by the smallest among them to get the simplest ratio.
4. Since the moles are expected to be in whole numbers, if you get a fraction, multiply all ratios by the same factor to get whole numbers.

For this particular question:

• 18.59 g O / 16.00 g/mol = 1.16 mol O
• 37.25 g S / 32.07 g/mol = 1.16 mol S
• 44.16 g F / 19.00 g/mol = 2.32 mol F

The smallest mole is for O and S (1.16 mol), so we divide each by 1.16 to get the ratio:

• 1.16 mol O / 1.16 = 1 O
• 1.16 mol S / 1.16 = 1 S
• 2.32 mol F / 1.16 = 2 F

Therefore, the empirical formula is OSF2.