Final answer:
To find the number of nitrogen atoms in 10.2 g of Copper (II) Nitrate, the molar mass and Avogadro's number are used to first calculate moles of the compound and then moles of nitrogen atoms, which are finally converted to number of atoms. The closest answer is (a) 1.21×1023 atoms.
Step-by-step explanation:
The question asks us how many nitrogen atoms are in 10.2 grams of Copper (II) Nitrate. To solve this, we need to perform a few calculations using the molar mass of Copper (II) Nitrate and Avogadro's number, which is 6.02 × 1023 atoms/mol.
First, we find the molar mass of Copper (II) Nitrate (Cu (NO3)2). Cu has an approximate atomic mass of 63.5 g/mol, each N has an approximate atomic mass of 14 g/mol, and each O has an atomic mass of about 16 g/mol. So the molar mass is approximately: 63.5 + (2 × 14) + (6 × 16) = 63.5 + 28 + 96 = 187.5 g/mol.
Next, we calculate the number of moles of Copper (II) Nitrate in 10.2 grams using the molar mass: 10.2 g / 187.5 g/mol = 0.0544 moles.
Since there are two nitrogen atoms per molecule of Copper (II) Nitrate, we double the number of moles to get the moles of nitrogen atoms: 0.0544 moles × 2 = 0.1088 moles of N.
Finally, we multiply the moles of nitrogen by Avogadro's number to get the number of nitrogen atoms: 0.1088 moles × 6.02 × 1023 atoms/mol = 6.55 × 1022 atoms. This answer isn't exactly one of the provided options but is closest to answer choice (a) 1.21×1023 atoms.