College

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 determine the number of moles of sulfur dioxide ([tex]\(SO_2\)[/tex]), we follow these steps:

1. First, calculate the molar mass of [tex]\(SO_2\)[/tex]. The molar mass is the sum of the atomic masses of its constituent atoms. Sulfur ([tex]\(S\)[/tex]) has an atomic mass of approximately [tex]\(32.06 \, \text{g/mol}\)[/tex] and oxygen ([tex]\(O\)[/tex]) has an atomic mass of approximately [tex]\(16.00 \, \text{g/mol}\)[/tex]. Since there are two oxygen atoms, we have:

[tex]$$
\text{Molar mass of } SO_2 = 32.06 + 2(16.00) = 32.06 + 32.00 = 64.06 \, \text{g/mol}.
$$[/tex]

2. Next, use the formula for the number of moles:

[tex]$$
\text{Moles} = \frac{\text{Mass}}{\text{Molar mass}}.
$$[/tex]

Given the mass is [tex]\(151 \, \text{g}\)[/tex], substitute the values:

[tex]$$
\text{Moles of } SO_2 = \frac{151}{64.06} \approx 2.357 \, \text{mol}.
$$[/tex]

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

[tex]$$
\boxed{2.357}
$$[/tex]

moles when expressed to three significant figures.