Answered

What is the empirical formula for a molecule containing [tex]46.8\% \, Si[/tex] and [tex]53.2\% \, O[/tex]?

A. [tex]SiO_2[/tex]
B. [tex]SiO_3[/tex]
C. [tex]Si_2O_3[/tex]
D. [tex]Si_2O[/tex]



Answer :

To determine the empirical formula of the compound in question, we will follow these steps:

1. Determine the number of moles of each element:

- Given percentages:
- Silicon (Si): 46.8%
- Oxygen (O): 53.2%

- Molar masses:
- Silicon (Si): approximately 28.085 g/mol
- Oxygen (O): approximately 15.999 g/mol

- Assume we have 100 grams of the compound. Therefore:
- Mass of Si = 46.8 grams
- Mass of O = 53.2 grams

- Calculate the moles of each element:
[tex]\[ \text{Moles of Si} = \frac{\text{Mass of Si}}{\text{Molar mass of Si}} = \frac{46.8}{28.085} \approx 1.667 \][/tex]
[tex]\[ \text{Moles of O} = \frac{\text{Mass of O}}{\text{Molar mass of O}} = \frac{53.2}{15.999} \approx 3.325 \][/tex]

2. Determine the simplest mole ratio:

- To find the simplest ratio, we divide the moles of each element by the smallest number of moles calculated:
[tex]\[ \text{Ratio of Si} = \frac{1.667}{1.667} = 1 \][/tex]
[tex]\[ \text{Ratio of O} = \frac{3.325}{1.667} \approx 1.995 \approx 2 \][/tex]

3. Write the empirical formula:

- The ratio of Si to O is 1:2.
- Therefore, the empirical formula is [tex]\(SiO_2\)[/tex].

Given the choices:
A. [tex]\(SiO_2\)[/tex]
B. [tex]\(SiO_3\)[/tex]
C. [tex]\(Si_2O_3\)[/tex]
D. [tex]\(Si_2O\)[/tex]

The correct answer is A. [tex]\(SiO_2\)[/tex].