The chemical formula for potassium bromide is KBr. A chemist measured the amount of potassium number of moles of potassium bromide produced m bromide produced during an experiment. She finds that 201. g of potassium bromide is produced. Calculate the an experiment. Round your answer to 3 significant digits mol
The Correct Answer and Explanation is :
To calculate the number of moles of potassium bromide (KBr) produced in the experiment, we need to use the following formula:
[
\text{moles of KBr} = \frac{\text{mass of KBr (grams)}}{\text{molar mass of KBr (g/mol)}}
]
Step 1: Find the Molar Mass of KBr
The molar mass of potassium bromide (KBr) is the sum of the atomic masses of potassium (K) and bromine (Br).
- Atomic mass of potassium (K) = 39.1 g/mol
- Atomic mass of bromine (Br) = 79.9 g/mol
So, the molar mass of KBr is:
[
\text{Molar mass of KBr} = 39.1 \, \text{g/mol} + 79.9 \, \text{g/mol} = 119.0 \, \text{g/mol}
]
Step 2: Use the Formula to Calculate Moles
The mass of KBr produced is 201.0 grams. Now, we can calculate the number of moles:
[
\text{moles of KBr} = \frac{201.0 \, \text{g}}{119.0 \, \text{g/mol}} = 1.689 \, \text{mol}
]
Step 3: Round the Answer to 3 Significant Digits
Since the given data (201.0 grams) has four significant digits, we round the result to three significant digits:
[
\text{moles of KBr} \approx 1.69 \, \text{mol}
]
Final Answer:
The number of moles of potassium bromide (KBr) produced is approximately 1.69 moles.
Explanation:
To calculate the number of moles of a substance, we use the relationship between mass and molar mass. Moles are a way of counting the number of entities (atoms, molecules, etc.) in a substance. By dividing the mass of KBr produced by its molar mass, we convert the mass into the number of moles. This is a standard calculation in chemistry, and the result provides an important quantity for further analysis of reactions and stoichiometry. In this case, rounding to three significant digits ensures the result is appropriately precise based on the given data.