Which of the following represents the number of carbon atoms in exactly 12 g of pure carbon-12?

• A. 6.022 × 10^{23}
• B. 12.0 × 10^{23}
• C. 1.00 × 10^{23}
• D. 3.01 × 10^{23}

Answer: (A)

Verified step by step guidance

1. Understand that 12 g of pure carbon-12 corresponds to exactly 1 mole of carbon atoms because the molar mass of carbon-12 is defined as 12 g/mol.
2. Recall that 1 mole of any substance contains Avogadro's number of particles (atoms, molecules, etc.), which is approximately \$6.022 \times 10^{23}$ particles per mole.
3. Since the problem asks for the number of carbon atoms in 12 g of carbon-12, you are essentially looking for the number of atoms in 1 mole of carbon-12.
4. Use the relationship: Number of atoms = (number of moles) \(\times\) (Avogadro's number), which simplifies here to \$1 \times 6.022 \times 10^{23}$ atoms.
5. Conclude that the number of carbon atoms in exactly 12 g of pure carbon-12 is \$6.022 \times 10^{23}$ atoms.