Question

The atomic mass of the element platinum (Pt) is 195.08 amu. How many atoms of platinum
are in 195.08 grams? (1 point)
3.087 × 10 atoms 21
1.175 × 10 atoms 26
6.022 × 10 atoms 23
1.951 × 10 atom

Answer 1

To find the number of atoms in 195.08 grams of platinum (Pt), we can use Avogadro's number, which is \(6.022 \times 10^{23}\) atoms per mole.

1. **Calculate the number of moles of platinum:**
The atomic mass of platinum is 195.08 amu, which means that 1 mole of platinum has a mass of 195.08 grams.

Therefore, the number of moles of platinum in 195.08 grams is:
\[
\text{moles of Pt} = \frac{\text{mass of Pt (g)}}{\text{molar mass of Pt (g/mol)}} = \frac{195.08 \text{ g}}{195.08 \text{ g/mol}} = 1 \text{ mol}
\]

2. **Calculate the number of atoms:**
Now, we use Avogadro's number to find the number of atoms:
\[
\text{number of atoms} = \text{moles} \times \text{Avogadro's number} = 1 \text{ mol} \times 6.022 \times 10^{23} \text{ atoms/mol} = 6.022 \times 10^{23} \text{ atoms}
\]

Thus, the answer is:
\[
\text{6.022 × 10}^{23} \text{ atoms}
\]

So the correct choice is:
**6.022 × 10​²³ atoms**.