High School

Type the correct answer in the box.

Sarah measures out 151 grams of [tex]$SO_2$[/tex]. How many moles is this? Express your answer to three significant figures.

151 grams of [tex]$SO_2$[/tex] is equal to [tex]\square[/tex] moles.

Answer :

To find out how many moles 151 grams of [tex]\(\text{SO}_2\)[/tex] (sulfur dioxide) is equivalent to, you need to use the molar mass of [tex]\(\text{SO}_2\)[/tex].

### Step-by-Step Solution:

1. Find the Molar Mass of [tex]\(\text{SO}_2\)[/tex]:
- The chemical formula for sulfur dioxide is [tex]\(\text{SO}_2\)[/tex].
- Sulfur (S) has an atomic mass of approximately 32.07 g/mol.
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol.
- Since there are two oxygen atoms in [tex]\(\text{SO}_2\)[/tex], the total mass for the oxygen is [tex]\(2 \times 16.00 = 32.00\)[/tex] g/mol.

Therefore, the molar mass of [tex]\(\text{SO}_2\)[/tex] is:
[tex]\[
32.07 \text{ g/mol (for sulfur)} + 32.00 \text{ g/mol (for two oxygens)} = 64.07 \text{ g/mol}
\][/tex]

2. Use the Molar Mass to Find the Number of Moles:
- To calculate the number of moles, you use the formula:
[tex]\[
\text{Number of moles} = \frac{\text{mass in grams}}{\text{molar mass in g/mol}}
\][/tex]
- For [tex]\(\text{SO}_2\)[/tex]:
[tex]\[
\text{Number of moles of } \text{SO}_2 = \frac{151 \text{ g}}{64.07 \text{ g/mol}}
\][/tex]

3. Calculate the Result:
- Dividing 151 grams by 64.07 g/mol gives:
[tex]\[
\approx 2.357 \text{ moles}
\][/tex]

Therefore, 151 grams of [tex]\(\text{SO}_2\)[/tex] is equal to approximately 2.357 moles.