The molar mass of silver (Ag) is 107.87 g/mol.
Calculate the mass in grams of a sample of Ag containing 1.97×10^22
atoms. Write your answer using three significant figures. gAg
The Correct Answer and Explanation is:
To calculate the mass in grams of a sample of silver (Ag) containing (1.97 \times 10^{22}) atoms, we can use the following steps:
Step 1: Understand the relationship between atoms and moles
First, we need to know how many atoms are in one mole of a substance. This is given by Avogadro’s number, which is approximately (6.022 \times 10^{23}) atoms/mol.
Step 2: Calculate the number of moles of silver
To find the number of moles of silver corresponding to (1.97 \times 10^{22}) atoms, we can use the formula:
[
\text{moles of Ag} = \frac{\text{number of atoms}}{\text{Avogadro’s number}}
]
Substituting the values:
[
\text{moles of Ag} = \frac{1.97 \times 10^{22} \text{ atoms}}{6.022 \times 10^{23} \text{ atoms/mol}} \approx 0.0327 \text{ mol}
]
Step 3: Calculate the mass of silver
Next, we can calculate the mass of silver using its molar mass. The molar mass of silver (Ag) is given as (107.87 \, \text{g/mol}). The mass can be calculated using the formula:
[
\text{mass of Ag} = \text{moles of Ag} \times \text{molar mass of Ag}
]
Substituting the values:
[
\text{mass of Ag} = 0.0327 \, \text{mol} \times 107.87 \, \text{g/mol} \approx 3.52 \, \text{g}
]
Conclusion
The mass of the silver sample containing (1.97 \times 10^{22}) atoms is approximately (3.52 \, \text{g}), expressed to three significant figures as 3.52 g Ag.
This calculation illustrates how to convert from the number of atoms to grams by utilizing Avogadro’s number and the molar mass, demonstrating fundamental concepts in stoichiometry and atomic theory. Understanding these relationships is essential for quantitative analysis in chemistry, as they provide a framework for converting between different units of measurement in chemical reactions and analyses.