Calculate the molar mass of argon atoms given that the mass of a single atom is 6.634×10^-26 kg.
The Correct Answer and Explanation is:
To calculate the molar mass of argon atoms, we first need to understand that the molar mass refers to the mass of one mole of atoms of an element. A mole is defined as Avogadro’s number of atoms, which is approximately 6.022×10236.022 \times 10^{23}6.022×1023 atoms.
Step 1: Convert the mass of a single argon atom into grams
The given mass of a single argon atom is 6.634×10−266.634 \times 10^{-26}6.634×10−26 kg. To convert this to grams (since molar mass is typically given in grams per mole), we use the conversion factor:1 kg=1000 g1 \, \text{kg} = 1000 \, \text{g}1kg=1000g
So, the mass of a single argon atom in grams is:6.634×10−26 kg×1000 g/kg=6.634×10−23 g6.634 \times 10^{-26} \, \text{kg} \times 1000 \, \text{g/kg} = 6.634 \times 10^{-23} \, \text{g}6.634×10−26kg×1000g/kg=6.634×10−23g
Step 2: Use Avogadro’s number to calculate the molar mass
The molar mass is the mass of one mole of atoms. We can calculate it by multiplying the mass of a single atom by Avogadro’s number:Molar Mass=(6.634×10−23 g)×(6.022×1023 atoms/mol)\text{Molar Mass} = (6.634 \times 10^{-23} \, \text{g}) \times (6.022 \times 10^{23} \, \text{atoms/mol})Molar Mass=(6.634×10−23g)×(6.022×1023atoms/mol)Molar Mass=39.98 g/mol\text{Molar Mass} = 39.98 \, \text{g/mol}Molar Mass=39.98g/mol
Conclusion
The molar mass of argon is approximately 39.98 g/mol39.98 \, \text{g/mol}39.98g/mol. This is the same value typically found on the periodic table for argon.
Explanation:
The reason the molar mass is essentially the atomic mass in grams is that the atomic mass unit (amu) is defined in a way that makes the mass of a single atom in grams correspond to the atomic mass in amu when you multiply by Avogadro’s number. Thus, for argon, the molar mass is nearly the same as its atomic mass, which is approximately 40 g/mol.
