The chemical formula for barium sulfide is BaS.
A chemist measured the amount of barium sulfide produced during an experiment. She finds that 11.7 g of barium sulfide is produced. Calculate the number of moles of barium sulfide produced.
The correct answer and explanation is :
The number of moles of barium sulfide (BaS) produced is 0.0691 moles.
Explanation:
To calculate the number of moles of a substance, we use the formula:
[
\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}}
]
Step 1: Identify Given Data
- Mass of BaS produced = 11.7 g
- Molar mass of BaS = Sum of atomic masses of barium (Ba) and sulfur (S)
- Barium (Ba): 137.33 g/mol
- Sulfur (S): 32.07 g/mol
- Total molar mass of BaS = ( 137.33 + 32.07 = 169.40 ) g/mol
Step 2: Calculate the Moles
Using the formula:
[
\text{Moles of BaS} = \frac{11.7 \text{ g}}{169.40 \text{ g/mol}}
]
[
= 0.0691 \text{ moles}
]
Step 3: Interpretation
This means that in the experiment, 0.0691 moles of BaS were formed. The mole is a fundamental unit in chemistry that helps in quantifying the amount of a substance based on Avogadro’s number (6.022 \times 10^{23}) entities per mole. This calculation is essential in stoichiometric reactions to understand the reactant-to-product relationships.

Here is the scientific illustration depicting the calculation of moles for barium sulfide (BaS), including a step-by-step breakdown of the process.