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 are in 151 grams of [tex]\( SO_2 \)[/tex], we need to follow these steps:

1. Find the molar mass of [tex]\( SO_2 \)[/tex]:
- Sulfur (S) has an atomic mass of approximately 32.06 g/mol.
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol.
- Since there are two oxygen atoms in [tex]\( SO_2 \)[/tex], we need to multiply the atomic mass of oxygen by 2.
- Therefore, the molar mass of [tex]\( SO_2 \)[/tex] is:
[tex]\[
32.06 \, \text{g/mol} + 2 \times 16.00 \, \text{g/mol} = 64.06 \, \text{g/mol}
\][/tex]

2. Calculate moles of [tex]\( SO_2 \)[/tex]:
To find the number of moles, use the formula:
[tex]\[
\text{moles} = \frac{\text{mass in grams}}{\text{molar mass}}
\][/tex]
For [tex]\( 151 \)[/tex] grams of [tex]\( SO_2 \)[/tex]:
[tex]\[
\text{moles of } SO_2 = \frac{151 \, \text{g}}{64.06 \, \text{g/mol}} \approx 2.357
\][/tex]

3. Express the answer to three significant figures:
The calculation gives us approximately 2.357. As needed, it is expressed to three significant figures.

Thus, 151 grams of [tex]\( SO_2 \)[/tex] is equal to approximately 2.357 moles.