Answer :
To find the number of moles in a 12.0-gram sample of [tex]\( \text{Cl}_2 \)[/tex], follow these steps:
1. Understand the Concept: The number of moles of a substance can be calculated using the formula:
[tex]\[
\text{Number of moles} = \frac{\text{mass of the sample (in grams)}}{\text{molar mass of the substance (in g/mol)}}
\][/tex]
2. Identify the Data:
- The mass of the [tex]\( \text{Cl}_2 \)[/tex] sample is 12.0 grams.
- The molar mass of [tex]\( \text{Cl}_2 \)[/tex] (chlorine gas) is 71.0 g/mol. This is because each chlorine atom has an average molar mass of 35.5 g/mol, and [tex]\( \text{Cl}_2 \)[/tex] consists of two chlorine atoms.
3. Calculate the Number of Moles:
- Use the formula:
[tex]\[
\text{Number of moles} = \frac{12.0 \, \text{g}}{71.0 \, \text{g/mol}}
\][/tex]
- Performing the division gives:
[tex]\[
\text{Number of moles} \approx 0.169 \, \text{moles}
\][/tex]
The correct option that matches this calculation is:
Option (2) [tex]\( \frac{12.0}{71.0} \)[/tex] mole.
1. Understand the Concept: The number of moles of a substance can be calculated using the formula:
[tex]\[
\text{Number of moles} = \frac{\text{mass of the sample (in grams)}}{\text{molar mass of the substance (in g/mol)}}
\][/tex]
2. Identify the Data:
- The mass of the [tex]\( \text{Cl}_2 \)[/tex] sample is 12.0 grams.
- The molar mass of [tex]\( \text{Cl}_2 \)[/tex] (chlorine gas) is 71.0 g/mol. This is because each chlorine atom has an average molar mass of 35.5 g/mol, and [tex]\( \text{Cl}_2 \)[/tex] consists of two chlorine atoms.
3. Calculate the Number of Moles:
- Use the formula:
[tex]\[
\text{Number of moles} = \frac{12.0 \, \text{g}}{71.0 \, \text{g/mol}}
\][/tex]
- Performing the division gives:
[tex]\[
\text{Number of moles} \approx 0.169 \, \text{moles}
\][/tex]
The correct option that matches this calculation is:
Option (2) [tex]\( \frac{12.0}{71.0} \)[/tex] mole.
