The chemical formula for barium oxide is BaO. A chemist determined by measurements that 0.035 moles of barium oxide participate in a chemical reaction. Calculate the mass of barium oxide that participates. Be sure your answer has the correct number of significant digits.
The Correct Answer and Explanation is :
To calculate the mass of barium oxide (BaO) that participates in the chemical reaction, we need to use the concept of moles and the molar mass of BaO. The molar mass is the mass of one mole of a substance, and it can be calculated by adding the atomic masses of the elements in the compound.
Step-by-step Calculation:
- Identify the molar mass of BaO:
- The atomic mass of barium (Ba) is approximately 137.33 g/mol.
- The atomic mass of oxygen (O) is approximately 16.00 g/mol. The molar mass of barium oxide (BaO) is: [
\text{Molar mass of BaO} = \text{Atomic mass of Ba} + \text{Atomic mass of O}
]
[
\text{Molar mass of BaO} = 137.33 \, \text{g/mol} + 16.00 \, \text{g/mol} = 153.33 \, \text{g/mol}
]
- Calculate the mass of barium oxide: We are given that 0.035 moles of BaO participate in the reaction. To find the mass, use the formula: [
\text{Mass} = \text{Number of moles} \times \text{Molar mass}
]
[
\text{Mass} = 0.035 \, \text{moles} \times 153.33 \, \text{g/mol}
]
[
\text{Mass} = 5.36655 \, \text{g}
] - Adjust for significant digits: The given number of moles (0.035) has 2 significant figures. Therefore, we should round the mass to 2 significant figures as well. [
\text{Mass} \approx 5.4 \, \text{g}
]
Final Answer:
The mass of barium oxide that participates in the reaction is approximately 5.4 g.
Explanation:
In this calculation, the key concept is the relationship between moles and mass. One mole of any substance corresponds to its molar mass in grams. When we know the number of moles involved in a reaction, multiplying this by the molar mass gives us the total mass of the substance. The significant digits are crucial in maintaining precision in the result based on the precision of the given values. Since the number of moles was provided with two significant digits, we rounded the result to match that level of precision, ensuring that our final answer reflects the accuracy of the input data.