What is the weight of 6.3 × 10

21
atoms of
phosphorus?
Answer in units of g

1mol of any substance = 6.022 * 10^23 elementary entities of that substance (be it atoms, molecules or whatever. Think of it as the chemist's "dozen" only it's 6.022 * 10^23 rather than 12.)

For finding the amount of grams in 1 mol of an element, find the element's atmoic mass and that number is the amount of grams.

6.3 * 10^21 P atoms * 1mol of P/6.022 * 10^23 P atoms * 30.97g of P/mol = 0.324g of Phosphorus.

Erm, *atomic mass, sorry.

To calculate the weight of a given number of atoms of phosphorus, we need to know the molar mass of phosphorus and use Avogadro's number.

1. Determine the molar mass of phosphorus (P) from the periodic table. The molar mass of phosphorus is approximately 30.97 g/mol.

2. Use Avogadro's number, which is approximately 6.022 × 10^23 atoms/mol, to find the number of moles of phosphorus in 6.3 × 10^21 atoms.

Number of moles = (Number of atoms) / (Avogadro's number)
= (6.3 × 10^21) / (6.022 × 10^23)
= (6.3 / 6.022) × (10^21 / 10^23)
= 1.045 × 10^-2 moles

3. Finally, multiply the number of moles by the molar mass of phosphorus to find the weight.

Weight = (Number of moles) × (Molar mass)
= (1.045 × 10^-2 mol) × (30.97 g/mol)
= 0.03232 g

Therefore, the weight of 6.3 × 10^21 atoms of phosphorus is approximately 0.03232 grams.